PNG or TIFF – Do You Know Which Format Won’t Hurt Your Scanned Photos?

From your site and the other information I’ve found on the net, I think we should scan our photo collections in TIFF, at 600 dpi, using your naming convention / workflow. You don’t cover TIFF versus other formats in your articles, but I see you are using that format and there seems to be general acceptance that it is the best format for archiving.

What do you think of the PNG format? 

Peter Fuller
Wellington, New Zealand

Peter, that is a great question. And you’re right, up until now I have not covered what I feel is the best file format(s) to save scanned photos with. But, as you astutely noticed, I did sort of allude to my personal choice in a couple of my posts. Especially in some of my images I used in my 3-part “naming convention” series you brought up called What Everyone Ought to Know When Naming Your Scanned Photos.

I think your question actually deserves a slightly more complex answer than I could normally get away with. Had you simply asked, “Which do you prefer for scanning photos, the TIFF or PNG format?”, I would feel comfortable quickly answering you that in my humble opinion, the TIFF format is by far more superior for the purpose of scanning photos. But, since you brought up your interest in “archiving” your photographs, I want to make sure I elaborate a bit more to explain why our personal goals of scanning need to be considered when making the final decision which file format to save our master image files.

PNG vs TIFF File GraphicPNG vs. TIFF Files – So Which IS Better?

PNG files (Portable Network Graphic) were invented to replace the GIF format (Graphics Interchange Format) that was quite popular at the time for images on the internet. They really weren’t intended to be used for professional-quality photos. Currently on the internet, you will primarily see JPEG and PNG files followed by the lingering GIFS.

PNG files:

  • can only be saved compressed (“lossless” – reduces file size)
  • can hold an alpha channel

I use PNG files here on the SYEL website a good portion of the time because they have small files sizes and I love being able to use the alpha channel. This is a fancy way of describing a “compositing” process where the image can have a transparent background so you can lay it on top of another image and use it as the first image’s background. It’s very cool! And in case you’re wondering, no, JPEG files don’t do alpha channels.

TIFF files (Tagged Image File Format) on the other hand:

  • can be opened with almost every image program (it’s an extremely common format)
  • can be saved compressed or uncompressed
  • can store “layers” within (great for use with Adobe’s high-end Photoshop for example)
  • can hold all color, color depths and color groups (like RGB and CMYK)
  • can save 16-bits per channel scans (your 48-bit scanner setting)
  • can store IPTC metadata (captions etc.)

In my opinion, one of the biggest reasons not to use the PNG format for photo scanning – and more importantly archiving photos – is because it’s a form of compression. It’s a form of compression called “lossless,” which as you might already know, means that your photo will be saved without having any of the data (details) of your photo “tossed out.” However, the image is still undergoing a very complex process using a mathematical algorithm to compress the file so that it will take up less space on your hard drive.

So let me explain why this should be important to you.

Do You Have Basic or Advanced Goals?

To keep it simple, if you are about to scan your entire photo collection, you are probably going to fall into one of the following two categories. First, you might be the type of person that just wants to get a good-looking scan of all of your photographs as quickly and easily as possible. If you feel this might describe your needs, I like to say that you are someone with basic goals.

Now don’t take that the wrong way. I don’t mean to say basic in a negative way. The fact that you are even wanting to scan your photos already says a lot about how much you care about your collection.

When Peter brought up archiving, to me it implies he’s stepping into the shoes of someone in the second category. Someone with advanced goals is a person I feel is invested from the very beginning to make the decisions that will insure everything they do throughout the workflow of scanning, correcting and managing their photos, will preserve every last bit of image quality (detail) they reasonably can. Those with advanced goals also are willing to sacrifice more of their time and possibly money – which in many cases is not that much more – for the ability to create and store these higher quality images.

Let me quickly add, having advanced goals is by no means exclusive to those seeking the level of perfection a lifelong professional in the graphic arts field would produce. You don’t need to be an expert to have advanced goals. We all have our own personal limitations and expectations for our collection.

Tiff Compression Window when Saving in Photoshop
Settings panel when saving a TIFF file in Photoshop CS5. (Mac) Notice there are three compression options or none

What I Really Think of Compression

I believe in my heart, that if you are going to really go at archiving your entire photo collection – I mean really give it your all – you should scan them with adequately high DPI settings, save them “raw” without lots of filters and computations altering the outcome of the master image during the scan, and save and archive them uncompressed. I know this might be asking a lot of you, but the sacrifice has its rewards.

If you are considering compressing your images, to save hard drive space or ease the processing load on your current computer, just know you are taking steps toward the side of people with more basic goals. I just want to make sure you understand this.

Many may disagree with me, but I consider compression, even the lossless kind, to be an act of compromise to the overall integrity of your collection.

The hugely popular JPEG file format (Joint Photographic Experts Group) also uses compression. And it’s even more severe because it’s a form of lossy compression. Lossy means your file size will typically be even smaller than that of lossless, but at the cost of reduced image quality. And once the detail is gone – it’s gone. If you’re lucky, your eye won’t be able to see what’s now missing.

Even worse, every time you re-save a JPEG as a JPEG, you are “tossing out” even more information in addition to the information you got rid of before. It’s compounding detail loss!

Non-destructive image managers will however automatically protect you from this additional image loss when you make edits to your photos inside. This is why I highly recommend everyone start using one. (Check out Use 1 of These 4 Photo Managers If You Care About Your Photo Collection)

Additionally, and I know this is really more theoretical, the second you bring to the table the option of compressing your masters, you introduce a greater possibility for file corruption. You’re putting more trust in that mathematical formula to “destruct” your photo now and “reconstruct” it later than you may want to give it. Some formats have so many variant types of compression, who is to say that “shareware” graphics program you found one day off the internet to compress your images will be around 20 years from now? What if  their proprietary scheme doesn’t open correctly in the version of Photoshop you buy in the future? Then what are you going to do?

The Best Format to Save Your Scanned Photos

You are the safest saving your master images in the most common, nonproprietary format that you possible can. And if you are swinging towards the advanced side of goals for your collection, you want to save your files uncompressed. Yes, uncompressed files are huge, but so are the capacities of average priced hard drives on store shelves today.

The two most common formats that I feel safe recommending to you are JPEG (high-quality setting) for those with basic goals and TIFF (uncompressed) for those with advanced goals. It’s also the two formats all of the major scanning services feel safe saving your precious memories in as well.

Wow! And I bet Peter thought this would be a simple answer to a simple question! Leave it to me – just get me all wound up and it all comes out!

I hope that all made sense. If I left out anything you are wondering about, just ask me in the comments below. I will be glad to answer them for you!

Thanks for that question Peter from over there in beautiful Wellington, New Zealand! And if you have a question of your own you would like me to cover in an article like this one, ask away using my contact form. Cheers!

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80 Comments on "PNG or TIFF – Do You Know Which Format Won’t Hurt Your Scanned Photos?"

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Yolanda Huang
Guest
February 26, 2012 11:53 pm

Got the answer I wanted on whether to scan my old family photos in TIFF or PNG format. I think I fall into the advanced side and am willing to spend more time and money (hard drive space) to preserve these photos. TIFF it will be. Now it’s just a matter of what DPI to set it at.

graig
Guest
graig
March 28, 2012 8:05 am

“Many may disagree with me, but I consider compression, even the lossless kind, to be an act of compromise to the overall integrity of your collection.”

i totally disagree. lossless compression means exactly that…. it’s won’t loose any quality. That means you could open and save it over and over and over again and it will always look the same. not a single pixel will change… Lossless compression should not be avoided. it’s a good thing.

besides, TIFF files can use LZW compression too, or even lossy jpeg compression. Avoiding lossless compression because it’s a form of compression is pointless.. PNG just has better lossless compression than TIFF.

the bad thing about tiff is that it has way more options. way way more. it’s had features added and supported and changed all over the place. i have had tiff files open with pieces removed. layers missing. layers doing something they shouldn’t be doing. because various programs don’t always save TIFF files in exactly the same way. Tiffs are overly complicated. besides if you accidentally have jpeg compression on when your saving your tiffs then your really messing up your images.

png being a standard hasn’t been changed very much. Png is ALWAYS a lossless format, and unlike TIFF there are no settings you can accidentally pick that would loose image quality. PNG offers lower file sizes, and you get the exact same image quality that you saved it as, just like tiff with no or LZW compression. And every program that saves a png can open it in exactly the same way… because it’s made to be viewable on the web. So in the future you know your image will be supported and openable.

i highly recommend PNG for image scans.

graig
Guest
graig
April 10, 2012 7:06 am

yeah, i don’t use either. i mostly take digital photographs, so really i am pretty done with scanning in general. i just use apple aperture, and throw all my raw images into that. it’s a really nice program for the price you pay. And hey, pentax uses lossless compression on their raw files smile

i can see your point about an archive though, if you want a museum like level of preservation. but even a lot of backup software will compress the data too.

“So how much risk are we talking here? Honestly, I am not qualified to answer that. But, also honestly, I’ve never had a .PNG file not open correctly — at least not that I was aware of. But why take any chances at all, I mean not even a .00005% chance if you aren’t gaining anything from it.”

i really don’t think theres any risk to using compression. The biggest risks to archival longevity are using incorrect backup strategies. I have lost data before. here’s how it went down. i had a DVD or a CD backup of my data. and my hard drive crashed.. problem 1 i only had one backup. 2 the DVD or cd with some of my images went bad, some of my images were gone. and some others were damaged. in this case maybe uncompressed tiffs would have made a difference to some of my damaged images, but then maybe not. The storage medium was damaged. hard drives crash… and the cd or dvd i used was kept in a dust free case. but it STILL failed.

So now i don’t trust any CD or DVR to backup… i use a hard drive backup, using time machine. and i also use online backup called crashplan. this way if my hard drive crashes, and my time machine drive burns out at the same time, i still have my online backup.

Art Taylor
Guest
Art Taylor
May 27, 2012 11:07 pm

For what it’s worth, here are my comments on file formats for archival images. As Curtis mentions, TIFF files are compatible across a wide range of scanners and computer platforms, (Mac, Windows, Linux) and virtually all professional, and many consumer-level, image editing software programs can read and write both compressed and uncompressed TIFFs. Having been developed before the advent of computers and desktop publishing, they were designed to include both bitmap graphics, like scanned images, and vector graphics created using mathematical formulae in programs like Adobe Illustrator and CorelDRAW. Today, Photoshop, Photoshop Elements, and probably other programs can create vector elements in bitmap files, using the Pen Tool and the Text Tool. TIFFs can include these vector lines and retain their editability, but PNGs need to have any vector lines rasterized or converted to potentially jaggy-edged bitmap elements. PNGs are also limited to 24-bit color depth, unlike TIFFs. While PNG might be OK for archiving original scans, if you are scanning for maximum quality at 48-bit (or 64-bit with the Infra-red dust and scratch channel included), TIFF is the better format. Also, once you have saved a COPY of your original scan and want to perform any editing on the copy, TIFFs will let you save and re-open any adjustment layers, text layers suitable for future editing of the text, any alpha channels or layer masks, and layers in general. While PNGs can preserve transparency, they do not retain layers as TIFFs do.

Back in the mid-’90s, the company that had developed the GIF format started to try to charge licencing fees to any company that wished to include GIF read-write capability in their software. Not surprisingly, this idea met with some opposition. The PNG format was developed to be an open-source format, that any company could freely use. It was intended to become a replacement for GIF, retaining the ability to include transparency as GIF can, while permitting the full 24-bit color depth of JPG. As Curtis has mentioned, JPG cannot include transparency. While it took several years for PNGs to become popular, their lossless compression, higher color depth, and transparency capability are now being recognized and more widely used. Another limitation of PNGs compared to TIFFs is that PNGs cannot incorporate EXIF or IPTC (the What, Where, When, Why, How) data in the image file. Such information needs to go into a separate side-car file which must be kept in the same folder as the PNG or it becomes separated and lost. EXIF and IPTC data can be included in TIFFs. Also, Adobe’s Lightroom, will not readily work with PNGs but has no problems with TIFFs.

Another format I don’t recall being mentioned yet is Adobe’s DNG (Digital NeGative). Since each digital camera manufacturer uses a proprietary RAW file format which is incompatible with any other manufacturer’s format (i.e. Canon/Nikon/Sony, etc. are incompatible and not interchangeable), and various versions within a particular brand may not be compatible with earlier versions from the same company (i.e. version 2 of brand X is not compatible with version 1 of brand X and cannot be processed using the different version’s conversion software), Adobe developed and released the open-source DNG format and encourages all the camera manufacturers to include DNG as a possible format in their respective cameras. The intent is to attain maximum future file compatibility for archives and libraries, much as the Adobe PDF format has achieved and retained near-universal compatibility for documents. Recent versions of Adobe software (Photoshop, Photoshop Elements, Lightroom) and other programs, such as Zoner Photo Studio Pro, VueScan Pro, can open DNG format files. VueScan Pro can also create DNG files as well as TIFF and JPG files as it scans.

Since DNG files, like RAW files, include all of the data captured by the scanner (or camera for RAW files) and do not do any image processing as for JPGs, maximum scanned data and image detail are available for processing at any time in the future. Color balance, color cast correction, exposure adjustment, etc. can be changed at any time using appropriate software. If one is shooting with a digital camera that provides a RAW option, the RAW file can be embedded in the DNG file so the original camera’s captured information is still available and can be edited in the appropriate camera RAW converter software.

My suggestion would be, and my practice is, scan using VueScan Pro, save as DNG and JPG, for ‘quick-and-dirty’ review and editing. Final editing is done using the DNG file. Note that the lower priced VueScan will not work with DNG format, the Pro version is required.

For backing up my photo archives (10s of 1,000s of slides plus hundreds of negatives and prints from over 40 years of personal photography), I burn at least two copies to DVD-R, using the slowest available burning speed. After burning the first copy, I visually check it in an image viewer/editor, usually Zoner Photo Studio Pro or ACDSee Photo Pro, to be sure it burned correctly, before burning the second copy. The second copy is also visually checked after burning. I do NOT use a back-up program to create archive backups. I drag-and-drop or copy-and-paste the original files to my burning software. This avoids any possible compression with backup software and any possible future incompatibilities with future versions of such software.

As newer media, such as Blu-Ray, come to dominate the market, my archives on DVD will be migrated to such media. When Blu-Ray starts to be replaced with something newer, the archives will again be migrated. Anybody have archived images or other files on floppy disks, ZIP or JAZ disks, or Syquest drives or tape drives that is no longer retrievable because the hardware is no longer available?

Art Taylor

Art Taylor
Guest
Art Taylor
July 17, 2012 10:01 pm

What Greg says about TIFF vs PNG is correct. As others have already mentioned, the other disadvantages of PNG, aside from needing an XMP ‘sidecar’ file for EXIF and IPTC data, are its lack of support for layers (useful for work-in-progress) copies of Photoshop/Photoshop Elements PSD files; and its inability to preserve color profiles. Possibly these limitations are why Epson and other scanner manufacturers don’t include an option to save scans as PNG files. Maybe someday, the ISO folks will provide a revised version that overcomes these shortcomings of the PNG format.

I didn’t realize the chances of multiple RAID5 drives failing were similar to or equal to those of a single drive failing. Like Curtis, I wouldn’t rely exclusively on RAID5 or any other version of RAID for backups and archives, although I see no problem using RAID5 as Part of a Backup and Archive Strategy.

‘Cloud’ storage may be relatively safe and secure, if not too expensive for large file volumes, but I’m concerned about the provider being there for months or years, then suddenly gone overnight, taking your files with it. As an option for one part of a backup and archive strategy, it’s probably worth considering but I’d hate to make it my only choice. Probably every ‘cloud’ storage provider uses multiple RAID drives, be they RAID5 or other, but what happens to your files if they happen to all be on the single RAID box that fails? What happens to your data if the provider suffers a catastrophic fire, flood, tornado, hurricane, or other natural disaster? Does your choice of storage provider offer geographically diverse storage facilities with redundant storage space in several locations for every customer?

I know both Apple and Microsoft offer ‘cloud’ storage space for free or very low prices and neither of these companies seems likely to vanish overnight. However, for many decades the Minolta camera company produced quality cameras, lenses made using glass ground in-house to their own specs, and introduced many innovative features in their cameras. They also produced several highly-rated scanners, both film and flatbed, over the years. Then one day in about 2005, they sold the camera production facilities to Sony, discontinued the production and support of their scanners, and completely exited the photographic camera, lens, and scanner markets. Fortunately for Minolta camera and lens owners/users, Sony has continued to provide at least some support for the Minolta cameras and the Sony Alpha D-SLRs use a lens mount compatible with the original Minolta auto-focus mount of 1985 so the older lenses can be used on today’s camera bodies. What do you do if you’ve made ‘cloud’ storage your only backup and archive medium and your provider suddenly vanishes, as Minolta did from the camera field? I’d strongly advise against using only ‘cloud’ storage with any provider.

Graig
Guest
Graig
July 18, 2012 7:58 pm

“Maybe someday, the ISO folks will provide a revised version that overcomes these shortcomings of the PNG format.”

I doubt it. the intended purpose of PNG was as a general purpose web graphic. though you never know.

raid is a good way to store images but not as your only storage medium. Drives fail. And if only one drive fails like it did, then at least it did it’s job in that situation. But that’s not the only thing that could go wrong with a raid setup. say you get hit by lightning and all your drives hardware gets fried and none of it works. It can happen. or maybe you just get a brownout and power surges, and multiple drives fail. don’t let raid be your only backup, i know you said you had the images on other drives too, which is definitely a good thing. one way to improve your backup even more is to have offsite backup.

One thing i use is a service called Crashplan plus. And it’s not really that expensive when you consider how much it costs to buy a hard drive. crash plan automatically backs up anything on your computer you tell it to backup, and saves it on their remote servers. so even if your house burns to the ground and all your computers and backups are destroyed. later when you get a new computer you can still restore your data with your crash plan account. and they offer unlimited data for your backups. you can buy it for a year, or more the more you buy the cheaper it gets. i bought a 5 year family plan, and even used it to back my mom’s computer up. recently her computer hard drive died and i used crash plan to restore all her data. crash plan is the best of those online backup companies, i can’t recommend it enough. crash plan works on windows mac and linux too.

John
Guest
John
September 10, 2012 11:01 pm

Art Taylor, I highly highly recommend against using optical media (DVD/Bluray) as a backup medium. DVDs and Blurays are very susceptible to “disc rot,” which is when the disc appears to be rotting from the inside, which results in data degradation. I believe it is due to rusting or some other chemical change happening within the disc. This is an extremely common phenomenon that can affect discs in as little as 2 years (I have seen it myself happening on large numbers of DVD-R/DVD+Rs, etc). Entire boxes of DVD-Rs can rot at the same time.

Please avoid using optical media as a backup medium.

Art Taylor
Guest
Art Taylor
September 24, 2012 9:49 pm

Hi John,

You are the first, and only, person I’ve learned of who has actually experienced the problem of ‘disc rot’. Although I’ve heard and read about ‘disc rot’, I’ve not recognized it IF I’ve had it happen to me. I’ve checked with others and they have also not recognized the problem, if they have it with their discs.

It would be beneficial to other readers of this blog, and to me, if you would send Curtis some photos showing any images damaged by ‘disc rot’ and any photos showing visual indications on either the label side or recorded side of discs exhibiting the problem. If we could see examples of the symptoms of ‘disc rot’, it might help us to learn if we have media with the problem. It would also be helpful to know specific brand names of discs you’ve noticed particularly susceptible to ‘disc rot’. If you’ve noticed any particular brand(s) showing problem after a specific period of time, it would be helpful to know the names involved. Are they name-brand media or generic, house-brands? I’m certain Curtis would be willing to post example photos, especially if you included a description of what they show, so please send him some examples to share with his readers.

I don’t doubt you’ve experienced ‘disc rot’ but without an accurate description of the symptoms, specific brand names, and photos showing examples of the problem, your warning is of limited value to anyone reading this blog.

Art

Graig Smith
Guest
Graig Smith
January 5, 2013 12:46 pm

I said in an earlier post what happened to me. i had burned cd disks and DVD disks. that even though they didn’t have a scratch on them, no dust on them. stored in a protective case for a couple of years they STILL went bad.. i lost some of the data on just a couple of my dvd disks. i permanently lost scans that i couldn’t get back. it was a bummer. and I also do not recommend storing anything in burned disk format. this comes from personal experience. it’s not a safe format to store things in.

nancy
Guest
nancy
November 19, 2012 12:33 am

so…here’s my question…
I’ve scanned both to .tiff and .jpg.
using .tiff on the prints that I want the best scan.
BUT when I upload them to popular places to print…they all end up converting them to .jpg anyway…so I’m not really gaining anything on the print…am I ??

If I scan to .jpg …I archive that file…and only make a duplicate for editing. am I still losing detail?

this is part of the “8 years between scans question for me!”

thanks.

Art Taylor
Guest
Art Taylor
November 19, 2012 11:01 pm

Looks like I might have beat Curtis to this response, Nancy. As you’ve discovered, most popular print places and photo sharing sites will convert your uploaded photos to jpg if you haven’t already done so before uploading. No, you’re not really gaining anything in print quality by scanning to .tiff IF you get prints done by an on-line company. You could likely get the benefit of your .tiff files if you put them on CD/DVD or USB stick and go to a place like Costco or other bricks-and-mortar store that offers digital printing.

While your .tiff files will take up more space for archiving, you retain more detail and quality for your archives with .tiffs. EVERY time you make a change to a .jpg and save it, you discard more detail and quality. You’d be better to scan routinely to .tiff, do any desired editing to the .tiff, then save an edited copy to .jpg for on-line printing or photo sharing.

One reason for the on-line companies converting everything to .jpg is simply that .jpg files are much smaller than .tiff files so they upload and download much more quickly and require less server space on their computers.

If your scanning software (EpsonScan and VueScan both do) and image-editing software (Photoshop Elements, Photoshop CSx, and some other programs do) offer the option to scan at 48-bit color instead of 24-bit color, using this option will give better color quality in your scans. While your monitor and any printer won’t be able to reproduce such a large range of colors, they do give better results when you do any editing or color-correction to your scanned images. To benefit from this color range, you must scan as .tiff since the .jpg format is limited to 24-bit color. When you’re done editing, save a COPY of your edited image as .jpg for viewing, sharing, and printing but keep your original .tiff with all the colors in case you later decide to re-edit for any reason. Feel free to contact me via Curtis’s blog if you have any questions about this.

Art Taylor

Malcolm
Guest
Malcolm
December 13, 2012 1:53 pm
Wow, this article has got a lot of traction, and (unfortunately) a little misinformation (not a lot, but…) First, on backup: a hard drive (in “time machine” or anything else) is NOT a backup. It is a copy, an offline copy (probably), and that is A Good Thing, but if one is concerned about optical media as a backup format, one should run screaming from any hard disk. The reason for this is that for backup you have be concerned about all sorts of failure modes, including the often overlooked “how will you read the thing in 10 years?” one (suppose you’d used SCSI disks as a backup media a decade ago… now what?). For an HDD (hard disk drive), you need to worry not only about media faults (not being able to read a particular chunk of media) but also motor/bearing/interface failures, which render the whole thing about as much use as a brick. But even worse, because HDDs have critical moving parts, they also need lubrication in order to work…. and that lubrication will evaporate over time. So eventually a disk sitting on a shelf will become a brick, and the only way you’ll get your data back is by spending a lot of money with a disk recovery business, and crossing your fingers. Optical media is preferable as long as the dyes in the media is archival grade and they are store properly… but the main reason to prefer it is that the media is cheaper (although the time to burn it isn’t, so that must be considered). Because the media is cheaper, the thinking goes, you’re more likely to have multiple copies, and because it is light and relatively robust, you’re more likely to have remote copies, too. The best media for backup is tape (still). Unfortunately, a sound backup strategy needs *2* tape drives (one to write, the other to verify), otherwise you risk creating backups that only one drive in the world can read… and that drive will be the one that just went up in smoke. The good news is that “cloud backup” services usually include tape-based backup of the storage, so this is (yet another) reason to go that route. By the way, if you do have a RAID drive fail, the best thing to do is to keep the whole thing running and use it as little as possible; don’t power it, or the attached computer, off until the new drive is installed (or ready to be installed if you don’t have hot plug), because a huge area of complexity for RAID controllers is figuring out which drives to use if, for instance, the formerly dead disk “gets better”. They should get it right, but it’s your data, not theirs, that will be corrupted if they don’t… Even more by the way: RAID1 is always a better choice than RAID5, except for the pesky issue of cost and connectivity. So six disks arranged as 3 RAID1 pairs is better than four disks as one RAID5 set, given that we’re all made of money! (Oh, wait…). Second, others have pointed out the fallacy of worrying about lossless compression. Certainly, if you save anything to a cloud, your data is going to be (losslessly) compressed anyway, so this is a non-issue. Third, the comments about vector formats being supported by TIFF are (at least partially) valid, but entirely irrelevant to a discussion about scanning. Sure, if you want a single file format for multiple types of image, then this is a very reasonable concern, but for scanning, you’re not going to be getting vector formats. Fourth, Adobe’s DNG is equally irrelevant to scanning, because DNG is a format designed to be a superset of camera sensor raw formats, and a lot of value of raw sensor data is that things like white balance and exposure can be tweaked. A good scanner will control those (the lamp produces the same color light, for example), so DNG doesn’t really have a role to play here. Fifth, as has been suggested above, the Achilles Heal of TIFF is that it is not fully standardized (the spec is actually copyrighted by Adobe), and (to make it worse) it is a “Container” type format (like AVI or MOV for video). So a TIFF file can have the image data in one of many formats, including lossy compression (JPEG, no less)! Of course, at first this is only a problem if you make it one (for yourself), but as a data interchange format, TIFF is a long way from being ideal. PNG is also a container-type format, but the structure of mandatory-vs-optional elements is much more rigorously defined. Sixth: PNG’s big strength is in the “P”: portable. the same file can be displayed on a phone, an iPad, any notebook or desktop machine regardless of whether it is a Mac, PC, or Linux (generally), because the rendering logic is built into all modern browsers (in fact, there are three little PNGs just below the text box in which I’m writing this). Seventh: the fact that any particular scanner does or does not support a given format is not intrinsically evidence of that format’s suitability for the task. Few scanner vendors care much about their software, and with higher-end applications like Silverfast, other considerations may apply (e.g. PNG requires compression, which requires CPU time, so saving files as uncompressed TIFFs is generally faster during the scan phase, although you may lose that time copying around larger files, and so on). Oddly enough, no-one’s mentioned JPEG2000, which is probably A Good Thing as it would just confuse the issue more (it’s another lossless format, but less well supported than PNG, so why bother….). Anyway, the bottom line is that whatever the source (camera, scanner, software) produces may well not be the best format for your personal workflow, and that format may not be the best for archival. Conclusion: (sorry it’s gone on this long…) there are plenty of subjective reasons to… Read more »
Art Taylor
Guest
Art Taylor
December 13, 2012 8:32 pm

An excellent point Malcolm makes is the need for TWO tape drives. This is an issue seldom likely to occur to most of us until it’s too late to do anything about it. I also appreciate his comments about TIFF vs PNG formats. Some valid points are raised.

Thanks, Malcolm for some excellent information about RAID. Any information about a RAID controller failure rather than a RAID drive failure? I seem to recall reading somewhere that a controller failure is at least as likely, if not more so, than a RAID drive failure. Do you know if one could leave the RAID drives powered on, although disconnected from the controller, while a faulty controller is replaced?

Malcolm touches on the issue of hard disk drive controllers when he mentions SCSI (Small Computer System Interface), which is used to be (but no longer are) standard on Macs and was available with an optional SCSI controller add-in card for PCs. The contemporary controller on PCs was IDE (Integrated Drive Electronics), later referred to as ATA, in turn superceded by EIDE (Enhanced Integrated Drive Electronics), then by SATA/PATA, and eSATA (for connecting external drives to the computer’s motherboard. See http://en.wikipedia.org/wiki/Hard_disk_drive#Access_and_interfaces for more information. Today’s PCs often don’t have IDE controllers so older hard disks may pose problems being connected to modern computers, let alone any internal mechanical problems such as Malcolm mentions, such as the lubrication drying out. Today, SSD (Solid State Device/Drives) are becoming common since they use no moving parts. A friend of mine has several older IDE/EIDE drives which he can no longer connect to his current computer since the computer lacks a suitable drive controller. To access any data on these older drives, he has to hook them up to an older computer in his computer room. Since he likes to tinker with computer hardware, he often has such a unit available but not always. For those who have only one computer available, this should be an item to seriously consider before deciding to archive exclusively to hard disks.

While I’ve had no personal experience with an SSD, one acquaintance of mine, who uses a very recent model Mac, has reported no problems with his SSD, although I believe he uses it for data storage rather than as the system disk with the Operating System on it. A friend, who built his own PC from parts a little over a year ago and who uses an SSD for his system disk, reports that while initially it was extremely fast in comparison with SATA drives he’d used previously, over time he has noticed its performance has slowed noticeably so that it seems to be no faster now than a SATA drive, installed at the same time, would have been. This MIGHT be just because he’s added more programs over time and no longer has as much free space available as he had at first. Maybe it’s a (common) feature of SSDs. Since I’ve heard of only these two specific drives, used differently by different individuals, I don’t want to draw any conclusions about the pros and cons of SSDs, just to mention there may be unforeseen differences which might cause one to consider if an SSD is worth the extra money for a comparable size disk instead of a SATA/USB/Firewire drive at present. Perhaps the SSD technology should be allowed to mature a little more before we all rush out and replace all of our present drives with SSDs. At best, we should be prepared to migrate our archived data to newer HDDs over time, as technology progresses, just as we needed to migrate it from Zip/Jaz to CD to DVD, and now likely to Blu-Ray, if we choose to use optical disks as part of a back-up and archiving strategy.

Art

Moe
Guest
Moe
January 5, 2013 11:26 am

You imply that with lossless compression there are “lots of filters and computations altering the outcome of the master image during the scan”. It seems odd to me that most scanning software would do this, but not implausible. Have you actually tested this and/or do you have any evidence you can point to? And if you did test this, was the final image quality affected to any discernible degree?

Graig Smith
Guest
Graig Smith
January 5, 2013 12:55 pm

“Optical media is preferable as long as the dyes in the media is archival grade and they are store properly…”

i disagree, as i said before, i had dvd disks go bad after only a couple of years. disc rot does happen. even if you have it stored in a dust free scratch free environment which is how i stored my disks. honestly. i have had better luck with hard drives. the only thing is hard drives are prone to catastrophical failures, where you can loose a whole disk at once. which is why i am using online backup. online backup. sends stuff out for backup hourly or so every time you add some images, it sends them off and they are already backed up. time machine isn’t the only backup i use. it’s just an extra. my main backup is crashplan’s service.

“The best media for backup is tape (still).”

i agree. all sorts of large data companies use tape backup. it’s reliable. i bet crashplan uses tape backup on their servers.

Art Taylor
Guest
Art Taylor
January 5, 2013 9:59 pm

Hi Graig Smith,

Can you send Curtis screen shots of any of the files from your dvd disks that have gone bad to show what the files look like when you try to view them? I’m not questioning the truth of your comments, just interested in seeing what disc rot actually looks like. Possibly other readers would also be interested in seeing what it looks like so Curtis could post any shots you might be able to provide him as a learning tool for all.

As Malcolm and I both mentioned late last month in this forum, hard disks can become unreadable, even if they’re in mint condition. Over Christmas, I visited a friend who had received a brand new Dell computer but he’s unable to connect the hard disk from his old computer to retrieve his data. The new computer has a totally different, although now standard, interface to control the hard disk(s) and it’s incompatible with the older standard. Fortunately, he believes he has most, if not all, of his images and other data transferred to CD since he’s unable to access the old hard disk. A few years ago, adapters were available to connect old disks to new computer mother boards so they could be used but when I checked online this week, such adapters were not to be found. Again, as Malcolm asks about SCSI drives, will today’s hard disks be accessible in a few years? This is a point worth considering. As with optical media or tape media, serious archival and backup strategies should include plans to migrate all data to new media every few years to retain accessibility.

Art Taylor

Graig smith
Guest
Graig smith
January 5, 2013 10:05 pm

Some of the files could not be read at all. This happened a few years ago. Threw the disk away. The cd drive would read and read. And then say disk could not be read. Happened on any drive. Some images I got off perfectly. And then others had damage. Where you couldn’t see some of the image. Or the file wouldn’t load at all.

HeavyDuty
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HeavyDuty
June 5, 2013 11:33 am

“Many may disagree with me, but I consider compression, even the lossless kind, to be an act of compromise to the overall integrity of your collection.”

There are no sides to this, nothing to disagree on. Lossless format is what the word says. I suggest getting more knowledge before _offering advice_ to people.

Mariano
Guest
Mariano
September 20, 2013 11:57 am

A couple of people with advanced goals suggest PNG is great.

Library of Congress accepts both uncompressed TIFF and PNG as for archival.
http://www.digitalpreservation.gov/formats/content/still_preferences.shtml

National Archives of Australia has chosen PNG as the “preservation format” for bit-mapped images and converts images in other bit-map formats to PNG during its ingest process.
http://www.naa.gov.au/Images/Digital-Preservation-Software-Platform-v1_tcm16-47139.pdf

Library and Archives Canada has adopted PNG as a recommended format for still images.
http://www.collectionscanada.gc.ca/obj/012018/f2/012018-2200-e.pdf

Dan
Guest
Dan
September 27, 2013 7:49 am

Your argument against compression seems completely illogical to me:

“You’re putting more trust in that mathematical formula to “destruct” your photo now and “reconstruct” it later than you may want to give it. Some formats have so many variant types of compression, who is to say that “shareware” graphics program you found one day off the internet to compress your images will be around 20 years from now?”

You’re putting trust in many “mathematical formulas” every time you use your computer for anything at all. What if the scanner driver accidentally sets every third pixel to a few shades lighter? What if the program you use to save the TIFF image is saving the TIFF incorrectly? You’re already putting your trust into far more places than you can possibly imagine by scanning and saving an image, so why sacrifice storage space to prevent an extremely obscure case of improper data compression?

If you use a well-known, well-tested image editor you’re not going to lose data by saving with a format that supports lossless compression. It’s called “lossless” for that very reason, and these algorithms are very well standardized. Most of these applications are even using the exact same library of code to perform the compression, not randomly making up their own.

If you’re worried about data loss, you’re looking in the wrong place. How many times have ACTUALLY heard of or witnessed an image editor compressing a common image format incorrectly and in an irreversible way? Now ask yourself, how many times have you heard of or witnessed a data storage device failing? I guarantee you’re infinitely more likely to lose data due to a hard drive failure and insufficient backups than a broken compression algorithm.

nicolas
Guest
nicolas
October 12, 2013 3:56 am

“I consider compression, even the lossless kind, to be an act of compromise to the overall integrity of your collection.”

that’s pretty bad claim belief in an structurally contradicting statement (what is the compromise of a lossless storage ? a lossless coding is a coding like any other, just more efficient), but to base and write a whole article on this single nugget of wisdom is plain fraud.

Elías
Guest
Elías
December 22, 2013 11:56 am

Hello everyone, I have another question for you experts: when I scan booklets of my cd collection and save to PNG and open them in photo managers, the scans appear not in the position you usually read them but in 90° angle to the right. Is there in loss when I rotate the scan 90° to the left with for example microsot office 2010? I’ve noticed the size of the file increasis a bit after a rotate and save and the increase varies depending on what photo manger I use for the task. Should I use any particular software for rotating them to the original “reading” position?

Thanks

Martin Feuchtwanger
Guest
February 18, 2014 5:07 pm

Elias, since no-one else has replied, i’ll offer my own not-too expert opinion:

No, rotating any exact multiple of 90 degrees will result in no loss to image quality because images are rectangular arrays of square pixels. (Rotating by any other angle, on the other hand, involves “re-sampling” and thus potential degradation of quality.)

Any slight changes in file size, if it occurs, is likely a result of other factors discussed at length above.

Kevin
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Kevin
July 8, 2014 9:51 pm

Lossless is *lossless*. Period.

Also, you can store EXIF metadata with PNG.

Wendy Lavender
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Wendy Lavender
January 8, 2015 4:19 pm

So does this mean I have to re-scan all my paper photos and slides that I’ve foolishly saved at .jpg?

Sven Clemens
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Sven Clemens
March 26, 2015 5:24 pm

From the point of a computer scientist I have to say you not really have a clue what you are talking about, if you are talking about compression. The term “loseless” in computer science (and so in this case too) means that you are able to reconstruct your original file (or image in this case) bit by bit without any variance.
You don’t get any information (which is what you call quality) more with an uncompressed tiff than anybody else with the same tiff compressed loseless.
The only difference will be, you have an file maybe 10 times as big as the compressed one.

The argument of proprietary algorithms who are not readable in 20 years are gibberish.
The most common algorithms for compression within TIFFs are LZW and ZIP.
The first one is around for more than 20 years and the second one is used for image-compression for more than 10 years. Each of them has plenty of libraries and programs who can decompress them and if there would be none of this tools left, they are documented this good nearly every programmer could recreate such tools within no time.
There are a much higher chance your HDD or filesystem will not be readable in 20 years than getting problem with zip-compression.

Marcell
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Marcell
October 29, 2015 10:45 am

Great point… I’m sorry you’d decided the troll way to put it.

Matt
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Matt
October 2, 2015 8:26 pm

Keep in mind that TIFF turns 30 in 2016. You should be able to easily open a 1986 TIFF file in todays graphics programs, and possibly even open one of todays images in a 1986 graphics program (that predates Photoshop by about 4 years). So for longevity, its hard to beat that.

Marcell
Guest
Marcell
October 29, 2015 11:03 am

basic or advance type of person? Curtis…. if we are reading your “sort” articles and posts… or those from Art… (no offense to any of you) we all have to be advance users smile

Good site!!!

Franklin Reid
Guest
Franklin Reid
November 22, 2015 3:10 pm

Just a note about the file formats you mentioned. This is very good information but I want to add just a little more to it.

I am a retired mechanical engineer and now I do freelance work at home. I use AutoCad 2010 and often go to a customer site to photograph a part of machinery or electronic equipment. I have learned that Autocad allows importing a photo onto a layer so I can then draw over it on another layer. But the Tiff and jpg images can’t be manipulated as much as the png image. Apparently AutoCad has accepted this file format to handle the best in a drawing.
I realize this will apply to very few of your readers if any at all. I just wanted to mention it to you.
Best Regards, Franklin Reid

j7n
Guest
j7n
February 3, 2016 7:00 pm

If you choose to use JPEG compression, be sure to disable Chroma Subsampling. Some software will not allow it to be configured, and will either always use it, which is very bad, or tie it to an overall quality slider. Chroma subsampling will halve color resolution, usually in both dimensions, which might not be noticeable on most images, but will be visible on red, saturated parts, such as fire or flowers. You might discover that those sections are blocky when you zoom in to them while editing, when it is already too late.

A scanner is almost equally capable of resolving any color, and delivering a ‘sparkling’ detail, if it is present in the copy.

My software has a dumb TIFF/JPEG writer which would aways use subsampling and produce significantly poorer quality at any setting, compared to plain JPG. Photoshop would open such files with nasty 2×2 blocks.

Quality 98 or Photoshop’s 12 is ‘nearly’ lossless, and an acceptable choice.

Debbie
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Debbie
March 7, 2016 10:19 pm

I have recently purchased the Epson V370 scanner with the intention of scanning my paper photos (again, as I want to scan at a higher (600) resolution). I haven’t started yet, aside from a couple of practice runs to check out the scan software (Epson Scan), mainly because I am not sure which format to scan in. I was going to use Tiff, for the reasons Curtis mentions but after reading this article and all of the comments I am confused, I didn’t even know about PNG, only JPG.
I would consider myself to have advanced goals rather than basic because archiving is important to me but I am relying on the scanning software and the expertise of other user’s knowledge and experience.
I do not have any numbers after my name and a lot of the comments went way over my head so to speak, so back to basics – Curtis do you still prefer to use Tiff 4 years from originally writing this article? I don’t mind spending time scanning and I have a separate hard drive to back up in.
Over the last two days I have read quite a few of your articles and really appreciate the effort you put into answering questions and comments as well as inspiring others to ‘get started’.

Debbie
Guest
Debbie
March 7, 2016 10:55 pm

I should mention that another reason for deciding on tiff is that I am scanning multiple photos and then need to crop them into single photos. I am assuming that the scan I make is scanned as one photo therefore when I crop them I am changing the dimensions of each photo which is why I think tiff will work better for me as the original sizes will remain the same. Or is there a better way of separating each photo when doing a multiple scan? As I mentioned in my previous post, I have the Epson Perfection V370 Photo scanner.
I also want to add the file names suggested in another article and add comments to each photo. Yep, long days ahead! smile

Art Taylor
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Art Taylor
March 8, 2016 6:38 am

Debbie, with Epson Scan you likely have a choice of saving as TIF, JPG, or PDF. You can choose any one format per scan. Please use the PDF option only for text documents, NOT photos. It compresses your files and makes it very difficult to edit photos. JPG files are always compressed so you will get better quality using TIF. If you invest in VueScan Pro (about $90.00), you can save each scan as a DNG (absolutely all the data your hardware can capture),TIF (loses some data through software processing, even without compression), JPG (always compressed), and as PDF. You have a choice of any single format or any desired combination of formats by checking the options on the OUTPUT tab in Professional mode. I recommend DNG for maximum quality plus JPG for immediate use without further editing other than resizing for web or email.

Debbie
Guest
Debbie
March 9, 2016 12:31 am

Thank you Art, you are right about the choices I have to scan, PNG is not an option, and I have started using Tiff. I can crop each photo while it is in preview and then the photos are scanned separately so it works well and I am happy with it. It took about 2 minutes to multi scan 6 photos. I will scan all my photos as Tiff even though I don’t intend to crop or edit a lot of them – YET. I’m sure if I scan certain photos as JPG, they will be the ones that I want to crop in the future, Murphy’s law and all that.
I have taken the wise advice in naming each photo with year/month/day and using xx when required. I am adding name/event/location then settings then giving them a number using the 00001 system, also using _ and -.
At the moment I am just adding these when I save the photo, I had a look at Picasa but it is being retired in favour of Google photos, see here http://googlephotos.blogspot.com.au/
I am about to check Google photos out as I would like to be able to leave a comment on each photo rather than in the name.

Nintendo Maniac 64
Guest
Nintendo Maniac 64
March 10, 2016 12:16 am

I just want to say a few quick things about PNG…

It actually does support 16 bit per channel, and from my experience any PNG viewer can handle 16bpc PNGs even if it can only display 8bpc.

Epson is a Japanese company, and from my knowledge Japanese businesses are typically quite conservative when it comes to adapting new technologies (especially in computer software*). Therefore, it’s very possible that PNG isn’t supported as a scanned “save as” format simply because it is a newer format (“only” 15 years) compared to JPEG, TIFF, BMP, etc.

Consider that Windows 7’s built-in TWAIN scanning software lets you save as PNG even if you’re doing so with an Epson scanner! (which is what I’ve been doing)

*Example: the 2011 PC version of the Japanese visual novel “Fate/stay night: Realta Nua” uses MPEG-1 (seriously?!) videos at 640×480 with “burned-in” letter-boxing (actual video content only uses 640×360 area).

Debbie
Guest
Debbie
March 17, 2016 11:09 pm

I have started scanning my photos using tiff and the ‘extended’ filenames and I’m happy with how it’s going. I do have a question regarding my digital photos though – it seems they are automatically jpg files of about 1-2 mb, obviously I can’t scan them as tiffs because they are digital, not hard copies (unless I have the last 15 years of photos printed!) so I guess they are already compressed and there is not much I can do with them? I have mostly used a point and shoot camera.

myownplayground
Guest
myownplayground
April 12, 2016 2:27 pm

Hi Curtis,

Thank you so much for all your work on this blog. It’s been incredibly helpful; I am just beginning to archive my family’s photo collections, and have found myself referring back to your site multiple times a day for weeks!

I finally decided to invest in the Epson V550, which is now set up. I’ve decided to use the .tif format (though I am curious about the .dng format and would love to learn more about the pros and cons). From what I’ve read, it seems you use the Epson Scan software, which is what I’m planning on using as well. Right now I’m in the File Save Settings within the program, but I see there are two ‘.tif’ options:

1. TIFF (*.tif)
2. PRINT Image Matching II (TIFF) (*.tif)

I looked up the difference in the user manual, and (if I am understanding it correctly) it says the latter will provide a higher quality scan for printing. First and foremost, my goal is to archive, but I’m sure at some point down the line I will want to print hard copies of some of the photos. That being the case, should I use the latter? Is there any reason to choose the the first option over the second? Any advice and information you can provide is appreciated!

And again – thank you so much for sharing your experience; it’s been invaluable!

tormaid
Guest
tormaid
May 5, 2016 10:26 am

What? Lossless compression is lossless. It is mathematically identical to the original, and just happens to waste less space.

Sheree
Guest
June 1, 2016 3:08 am

Nice answers in return of this query with real arguments and describing everything regarding that.

Mandy
Guest
July 3, 2016 8:57 pm

Nice article..photocopiers are very important for office promotion..thanks for sharing

payday loan
Guest
July 14, 2016 11:00 am

Hello there, You’ve done an incredible job. I’ll certainly digg it and personally recommend to my friends. I am confident they’ll be benefited from this website.

Barbara
Guest
Barbara
August 3, 2016 8:51 am

Glad I found your website. I am so uninformed on this I only understood about a 10th of the discussion. But, I feel as if I have found a source that with study will help me to become more informed before I begin to scan my 30 years of photos of Switzerland. I am eager to start the scanning, but first, the learning. Thanks!

Martin Karlsson
Guest
Martin Karlsson
August 14, 2016 6:17 am

What about tags in the files? Is anybody using this?
In windows explorer there is only one field for PNG and that is ‘date taken’. This cannot contain ‘x’.
For TIFF there are a whole lot of fields to use. Any suggestions on which fields to use for extended filenames?
[date] – [event] – [location] – [people] – [scanner settings] – [numbering system].tiff
The field ‘tags’ seems useful for searchable tags for example all of the persons in the photo, location etc. This is searchable in windows explorer. Can these fields be read by a photo managing software?

I’ve bought a Canon CanoScan 9000F Mark II for my retired mother to scan our photo collection. She hasn’t started yet as I’m still doing research.
I’ve really learned a lot from this site. Thank you!

Rex
Guest
Rex
August 29, 2016 7:46 pm

Interesting article. Thank you for publishing it. I am confused, however, about the compression vs. non-compression issue. To get right to it, I’m not sure why using compression makes a person a basic need person, or why that’s relevant.

From my perspective, using more disk space than one needs to doesn’t make sense. If you can store the exact same file for less, than it makes sense to do so, regardless of whether you’re a basic person, advanced person, or an upside-down pineapple cake. Just using more space because you have “advanced” needs, without a benefit for that increased space usage, all to retain a mental image of oneself as an advanced user, doesn’t make sense. This is like saying “basic people pay $1.99 for a taco, but advanced people should pay $3.99 for the exact same taco”.

Well, why?

I guess I’m just not getting it.

Interesting article, though.

Art Taylor
Guest
Art Taylor
August 29, 2016 8:38 pm

Hi Rex,

I believe why Curtis refers to some people as ‘basic needs’ people is that they need only to have an acceptable quality of digital image. They’re generally not concerned about preserving the maximum possible file data and quality that other people, who may want to do so in case they want to edit their images for particular needs in the future. So far as compression goes, if it’s LOSSLESS compression, then no data or quality is lost to the compression operation. On the other hand, LOSSY compression does discard some data and quality. The greater the amount of compression, the greater the loss of data and quality. While the TIF/TIFF format is generally LOSSLESS, it can be set to use JPG/JPEG LOSSY compression, at least in some programs. If the same image is scanned as a TIF, then again as a JPG, the two files will NOT be identical since the JPG format always applies at least some compression. Thus, you don’t have the “exact same file for less” with the JPG instead of the TIF version. For people who just want a digital copy of an original photo, particularly if all they want to do with the digital image is email it or post it on a blog or web site, the JPG version, which will be smaller than the TIF version, will most likely meet their needs, regardless of the amount of compression applied. Becaused the JPG format is LOSSY, each time a JPG file is opened, edited in any way, then re-saved, it is compressed again so repeated saves continue to reduce the amount of data in the file and the file’s quality. TIF and PNG formats, both using LOSSLESS compression, if any, normally give larger file sizes but don’t lose any image quality. For those who want to retain the maximum possible quality and/or do extensive editing, possibly intending to eventually print their images, TIF and PNG are better formats to use. Such files can always be converted to JPG after editing and, if necessary, resizing, for use in email or posting online. Hopefully this will clarify things for you.

Rex
Guest
Rex
August 31, 2016 12:07 pm

Ah, okay, so he’s talking about lossy compression then? He doesn’t have an objection to flipping on LZW or ZIP compression when saving the TIFF?

If so, that makes complete sense.

For some reason, I thought he was saying “Don’t use LZW or ZIP compression on TIFF files if you’re an advanced user”, and that’s what I didn’t understand. I thought there was some philosophical objection to any compression for “advanced” users.

It sounds like my interpretation was incorrect.

Thanks for the help!

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