Advice on File formats

Discussion in 'Photoshop Tutorials' started by Glenis, Feb 13, 2007.

  1. Glenis

    Glenis Guest

    Hi,
    My digital camera delivers JPGs (OK, it's not a fancy camera but seems
    OK for my purposes).
    When I import them into PS I immediately save them as PNGs for purposes
    of editing/cropping etc. This seems an OK proposition since:
    a: Quality isn't degraded following multiple edits/save
    b. It's a format that's accepted for publishing to the Web (I have a
    couple of photo websites and a Flickr account)
    c: File sizes are not too large

    Another thing I do with my photos is upload them to BonusPrint in order
    to obtain prints. However, BonusPrint accept only JPG, BMP and TIFF
    formats so I have to convert the PNGs to TIFFs in order to upload them.

    My question is this:
    Am I reducing the quality of my photos by initially converting them to
    PNGs?. Should I save them as TIFFs?
    Your suggestions please.
     
    Glenis, Feb 13, 2007
    #1
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  2. I doubt there is any loss in quality going from a PNG to TIF. However, I do
    have wonder why PNG. It is pretty much a dead format and isn't even very
    well supported by most browsers. If I was going to choose a format to
    convert my images to from the cameras JPG's it would be TIF. Very wide
    support, offers compression without image data loss and more.

    ljc
     
    Little Juice Coupe, Feb 13, 2007
    #2
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  3. Glenis

    Glenis Guest

    Why PNG?
    Well, it seems to display fine in browsers I use (IE7, Firefox2 and
    Opera), it's lossless & file sizes are relatively small.
    What alternative is there to PNG?
    TIF isn't supported by browsers at all and file sizes are BIG.

    My question regarding quality degradation in converting from JPG to PNG
    is to do with my confusion on this 8-bit/16-bit option in PS
    (Image-Mode). I'm a little unclear as to how an 8-bit image can have
    more than 256 colors.
    Perhaps you can point me at a good information source/book.
     
    Glenis, Feb 13, 2007
    #3
  4. Glenis

    tacit Guest

    No. PNG, like TIFF, is lossless. You can change between lossless file
    formats with no degradation at all.
     
    tacit, Feb 14, 2007
    #4
  5. Glenis

    tacit Guest

    You are confusing 8 bits per CHANNEL with eight bits per PIXEL.

    Eight bits per CHANNEL means eight bits of red, eight bits of green, and
    eight bits of blue, for a total of 24 bits per pixel and a total of 16
    million colors.

    Eight bits per PIXEL means each pixel is made of a total of eight bits,
    for a total of 256 colors maximum.
     
    tacit, Feb 14, 2007
    #5
  6. Glenis

    Glenis Guest

    Thanks.
     
    Glenis, Feb 14, 2007
    #6
  7. Glenis

    Owen Ransen Guest

    Owen Ransen, Feb 14, 2007
    #7
  8. Glenis

    Owen Ransen Guest

    Which browsers support TIF?


    Easy to use graphics effects:
    http://www.ransen.com/
     
    Owen Ransen, Feb 14, 2007
    #8
  9. Glenis

    Glenis Guest

    Yeah, thanks for that.
    Being fairly new at this, I was just wondering if I had missed the obvious.
    However, it seems to me that PNGs, being lossless and supported by the
    main Browsers is a pretty good format with which to save images
    (although I was a little surprised by the comment by
    Little Juice Coupe
    If PNG is 'pretty much dead' then what's the alternative?
    JPG is maybe ubiquitous but it's lossy and I don't like the sound of
    lossy at all.
    TIFF (as far as I can discover) is a pretty old format and I can see no
    good reason for using it. OK, it's lossless but it produces BIG files,
    is not compatible with Browsers and if one uses Photoshop then you may
    as well stick to PSD for Layers etc.
    But for archiving purposes I'm not too sure which format will be the best.
     
    Glenis, Feb 14, 2007
    #9
  10. Nothing was said about the web in the OP except as a side note and not as
    the main reason he was converting his JPGs to PNG.

    ljc
     
    Little Juice Coupe, Feb 14, 2007
    #10
  11. That is the problem. Microsoft did a great job of ensuring the PNG would
    never be widely adopted and it isn't. Sure most programs will save it but
    few browsers full support the format. The web has two major image formats
    like it or not and those a JPG and GIF.

    Your original post only mentioned the web as a side note. It seemed that you
    were more interested in a format that wasn't lossy to store your digital
    camera images as and that format is TIF. If you need to put them on the web
    you are most likely going to have to resize them down anyways so PNG isn't
    really a benefit.

    There is also no guarantee that PNG will be supported in a few years. TIF
    will be since Adobe owns and controls it.

    ljc
     
    Little Juice Coupe, Feb 14, 2007
    #11
  12. Glenis

    Glenis Guest

    Well, Web compatibility was one of the reasons for my choosing PNG.
    See:
    The only PNG issues I've heard of re the Web is Transparency, which
    doesn't bother me.
    You suggest that TIFF will always be supported since Adobe owns/controls
    it. Isn't that also the case with PSD? (smaller file sizes).
    What about compressed TIFF (LZW)? Apart from file size, what is the
    difference?
     
    Glenis, Feb 14, 2007
    #12
  13. Well, Adobe is moving away from PSD. They don't plan to end support for it,
    but they do encourage people to move to TIF that is the format that they are
    developing more strongly now (this according to posts from Adobe personel on
    the Adobe user forums).

    The problem with PNG is far few programs support it than do. As I said
    Microsoft did a very good job of killing it. Right now it is only a nitch
    format and I don't know about anyone else I am not about to store my images
    in a nitch format.

    The other issue with PNG besides the transparency in browsers comes in to
    play with color management. PNG doesn't do it well and many programs don't
    support that well.

    There is a reason why most professionals use TIF for both printing and
    storage. As far as compression with TIF, I don't find it makes a whole lot
    of difference and not all programs (most old, shareware, freeware program)
    don't support it. Just like very few programs support TIF files with layers.
    But, flattened plain old TIF files are a much better archiving option than
    PNG. Show me a professional photographer that saves in PNG and I will show
    you a photographer that isn't professional. Show me a printer (pre-press
    hear) that accepts images in PNG and I will show you a not so hot printer.

    The fact remains you will be able to read TIF files for far longer in to the
    future than you will PNG. The only other format that I think has this kind
    of life potental is JPG. And, because of its lossy nature is not someting I
    would save my images to. I have no problem archiving my cameras JPGs as JPGs
    becaue if I need to work on them I will save them as TIF while I do so and
    would probably not ever take it back to JPG unless it was going back on the
    web. But, for archiving without ever resaving JPG is just fine.

    ljc
     
    Little Juice Coupe, Feb 15, 2007
    #13
  14. Glenis

    JJ Guest

    Can you give us URLs to those posts? I find it hard to believe that
    Adobe is moving to TIFF. DNG, perhaps, because it is an extension of
    TIFF, but TIFF itself?
     
    JJ, Feb 15, 2007
    #14
  15. Paul Hartman/Dirty Linen, Feb 15, 2007
    #15
  16. John McWilliams, Feb 15, 2007
    #16
  17. Glenis

    Aaron Sun Guest

    JPG is fine for most purposes. If you set the quality to 12 (Maximum) it is
    the same as a lossless image, meaning no data is lost and your picture will
    be exactly how you left it.
     
    Aaron Sun, Feb 15, 2007
    #17
  18. Glenis

    tacit Guest

    False.

    Absolutely false. Even at quality 12, there is still loss. This JPEG
    setting absolutely IS NOT lossless, as saving an image in JPEG and the
    same image in TIFF and then placing the two images over one another in
    Difference mode will show.
     
    tacit, Feb 16, 2007
    #18
  19. Glenis

    Glenis Guest

    OK. Thanks.
    I'll look again at TIFFs although I'm not convinced away from PNGs. All
    software and OS's I've used in the last few years have supported them,
    including Windows and IE. Maybe there are color management issues but
    not enough that I've noticed. Of course, I'm not a professional
    photographer and am highly unlikely to print them pre-press or even locally.
    BMPs are far more ancient (who still uses them?)and yet they're still
    supported pretty much universally.
    The TIFF spec hasn't been updated since the early 90s I believe so
    either that makes it perfect or else it's getting long in the tooth.
    But JPG I'll always avoid where possible.
     
    Glenis, Feb 16, 2007
    #19
  20. I have done a search on the Adobe forums and unfortunately they don't go
    back far enough. This was early 2006 and it was Chris Cox that brought it
    some one someone was talking about archiving their images in PSD because
    they felt it was the more future proof format. It was then that Chris said
    Adobe was moving away from PSD and doing more with TIF. However, he also
    said that there are no plans to end PSD support in Adobe products (those
    that do support it like Photoshop) anytime soon. The reasoning given was
    that TIF can do everything PSD can, but it is much more extensible and
    easier to keep backwards compatible (though not always like with layers in
    TIF files).

    ljc
     
    Little Juice Coupe, Feb 16, 2007
    #20
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