Discussion in 'Digital Photography' started by Caien, Mar 21, 2007.

  1. Caien

    Mardon Guest

    I use Photoshop, so I'll speak to that software. If you plan to do all of
    your editing in a single session, then it is unecessary to save your work
    to a lossless format before editing. As others have suggested, it is a
    good idea to always work on a duplicate copy of the original jpeg image and
    save that original in a safe place. Saving to jepg does not cause the
    image that is still being worked on within the editing software to lose
    quality. The quality loss that people are talking about occurs during the
    process of saving the image to jpeg. If you save an image to a lossy
    format like jpeg, and subequently load that image into your editing program
    to do more editing, then you will be working on an image that has had loss
    introduced and this is not a good thing to do. Supposing, however, that
    you want to save a jpeg image to two different sizes. You can save the
    larger image first, then resample to a smaller image and save that one.
    This does not introduce anymore loss than if closed the program after
    saving the first file and reloaded the original image before resampling for
    the smaller file. BTW, it does help a bit if you shoot in Adobe RGB color
    space and don't convert to sRGB until the final file is saved.
    Mardon, Mar 21, 2007
    1. Advertisements

  2. Caien

    alex Guest

    Definitely. I would use your favorite editor's format for this.
    I would avoid this and save edited photos in a standard, lossless,
    compressed format (png is my first choice, tiff a distant second).

    Standard, so you are not tied up to a specific program or OS. Further,
    if 50+ years later your kids want to see those pictures they will not
    have to fish for some obscure software that was written by a company
    long gone and only runs on hardware that has not been made for decades.

    Lossless. When saving in JPEG the errors accumulate. With lossless
    format you can continue making small changes in the future.

    Compressed, so the files are (somewhat) smaller.

    You pay for losslessness with bigger files (maybe 1.5MB per MP, ~15MB
    for a 10-MP image, YMMV), but with current prices for hard drives the
    additional cost for extra storage and backup is minimal.

    For specific format choice: I like png, tiff is OK as well. There is an
    OK (compression-wise) lossless mode in JPEG 2000 but it is not too
    popular. Finally, some basic operations (rotation, cropping) can be
    done losslessly for JPEG and there are free programs to do this.
    alex, Mar 21, 2007
    1. Advertisements

  3. Caien

    Ken Lucke Guest

    The text doesn't duplicate what happened from the beginning, only tells
    you how you got to where you are at the moment. I'm looking more for
    something that would merely save the original file and the steps
    applied to it (like Aperture or Lightroom do) up to thhe presenet - in
    effect, non-destructive editing. Admittedly, that would be quite a
    history trail on some peoples' images, so I don't ever expect it to
    happen (even though I would suppose it could easily be programmed to be
    toggled on and off as desired per image).

    You need only reflect that one of the best ways to get yourself a
    reputation as a dangerous citizen these days is to go about repeating
    the very phrases which our founding fathers used in the struggle for
    -- Charles A. Beard
    Ken Lucke, Mar 21, 2007
  4. Yet, did not the OP ask about saving in TIFF? So how much different is this
    compared to saving in PSP or PS native file formats?
    Ed Ruf (REPLY to E-MAIL IN SIG!), Mar 21, 2007
  5. Caien

    HEMI-Powered Guest

    Today, Ed Ruf (REPLY to E-MAIL IN SIG!) made these interesting
    comments ...
    They are clearly different depending on whether TIFF compress is
    or is not used and PSD vs pspimage both vary widely depending on
    the content of what is being stored. But, my comment stands, at
    least for myself. When I want full capability, which is VERY
    rare, I use pspimage, else JPEG. Why is that so much heresy to
    you and ther other purists around here? It isn't the format that
    is at all important, it is the content of the image both
    artistically and technically.
    HEMI-Powered, Mar 21, 2007
  6. Why? Since it would seem your editing technique apparently does not make
    use of adjustment and/or mask layers why would you waste 2x as much space
    as using say JP2K in lossless mode to save for even your full capability
    Maybe because some of us have seen the benefits to have graduated to making
    our edits in 16 bit space? But I see you have all ready begun your classic
    escalation posting technique and begun the name calling. What's next the
    foul language ridden posts?

    Believe it of not many folks who visit this forum are actually interested
    in printing their photos and want the prints to be the best they can. It's
    funny though you don't get the 8 vs 16 bit editing issue since all you care
    about is viewing on a monitor, which can more easily show the limitations
    of this. And if you don't get this, you'll never understand why some shoot
    raw for some things.
    Ed Ruf (REPLY to E-MAIL IN SIG!), Mar 21, 2007
  7. Caien

    HEMI-Powered Guest

    Today, Ed Ruf (REPLY to E-MAIL IN SIG!) made these interesting
    comments ...
    You are an elitist and a prima donna who cannot bring themselves
    to even consider alternative views than your own, so enjoy
    yourself as you do things and I will do the same.
    HEMI-Powered, Mar 22, 2007
  8. Caien

    Ron Hunter Guest

    Maybe. IF you intend to do multiple edits in multiple sessions, with
    frequent saves, and reloads, it might be to your advantage. For a
    single session, with multiple edits, no. For multiple edits, in
    multiple sessions, yes. Either way, you probably won't see visible
    degradation over the course of 10 edit sessions, unless you set the
    program to save the .jpg files at very low quality settings.
    Ron Hunter, Mar 22, 2007
  9. Caien

    Signal Guest

    I don't know if this is what you're after (this is rather basic and
    you sound like you have expereince) but here's a little guide to using
    Signal, Mar 22, 2007
  10. Caien

    Martin Brown Guest

    A lot of people are afraid of losing data when in fact a first
    generation JPEG loss at high quality is usually negligible for most
    photographic source material. However, each time you go around the
    open edit save loop with JPEG you get cumulative errors. And some
    operations like cropping on an odd pixel boundary for instance are
    particularly destructive to colour fidelity in default JPEG 2x2 chroma
    subsampled images.

    You do the cause of defending JPEG from unfair criticism no good at
    all when you advocate using it for temporary saved intermediate work
    files - a task fro which it is singularly unsuited when compared to
    any of the lossless formats. And especially when compared to the
    native format of whichever application you happen to use since that
    usually supports layers etc.
    A lossless format minimised artefacts and for temporary workflow files
    has its advantages - but I suppose it depends how tolerant you are of
    colour dirft and loss of edge detail. YMMV

    Martin Brown
    Martin Brown, Mar 22, 2007
  11. Caien wrote
    There's some good advice in this thread but whatever you choose
    to do, if you have an image that you want to keep for posterity, make
    a back-up copy of the oeiginal file somewhere, perhaps on CD,
    write-protect it and don't change it. Whatever then happens down
    the line with whatever application/format you choose to manipulate it,
    at least if it all goes pear-shaped you've still got the original
    in the bank and can go back to it.

    Chris Gilbert, Mar 22, 2007
  12. Caien

    Signal Guest

    The "fine" JPG images coming out of my camera have worse artifacts
    than RAW images which I convert manually. :(
    Signal, Mar 22, 2007
  13. When viewed how?

    David J Taylor, Mar 22, 2007
  14. On a recent trip, I took all my photos in high quality JPG's. Does it make
    If you are going to do the editing in more than one session then yes.

    For example, suppose it takes you three goes before you get it right. If
    you don't use a lossless format to save between whiles you have:

    Load->Edit1->jpeg save Load->edit2->jpeg save Load->edit3->jpeg save

    jpeg save is the only step which introduces a loss of quality and in the
    above example you've got three of them.

    Use TIFF between whiles and you only have one jpeg save. QED.

    If you are going to do all the edits in one session then it makes no

    Keith Sheppard, Mar 22, 2007
  15. I suppose now we'll start the perennial "the more mega pixels theI recently upgraded my camera for various reasons, none of them associated
    with megapixels, but because of the way the industry is going I ended up
    with three times as many megapixels as I had before.

    There have been a number of consequences of this. I've had to buy a bigger
    pen drive to carry my pictures around. I've had to buy a DVD burner because
    I can no longer fit a year's pictures on a single CD and I have to reduce
    the resolution before posting or sending pictures over a dial-up link.

    Have I noticed a marked improvement in picture quality? Er, no. In fact
    I'm darned if I can notice _any_ improvement in picture quality really.

    Yes, sure I could set my new camera to less than its maximum resolution but
    that seems a bit of a waste and sure as eggs is eggs, the day after I did
    that I'd take the best picture of my life with a little bit in one corner
    really aching to be blown up large - but it hasn't happened yet.

    I've always gone for cameras with big optical zooms because I'm too lazy to
    do much post processing, so I guess that could be a factor, but I'm firmly
    in the "megapixels are overrated" camp.

    Keith Sheppard, Mar 22, 2007
  16. Caien

    Martin Brown Guest

    I'd be interested in seeing a sample JPEG image that you think shows
    this problem. Most often the things that JPEG gets blamed for are
    actually the result of excessively brutal in camera sharpening.
    Manufacturers have learned that sharpness and MP count sells cameras -
    both are very easy to measure in reviews.

    Raw gives you more control of shadow/highlight detail and generally
    applies a less brutal sharpness filter by defult.

    There are a few manufacturers that do use hgher levels of JPEG
    compression for the "fine" settings as well as a few like Nikon and
    Pentax which err on the side of extreme caution to a point where max
    quality JPEG file size increases without making a significant
    improvement. Most are sat somewhere inbetween the two.

    A rough rule of thumb is that a contrasty sunny sharp landscape with
    lots of forest detail and an interesting sky will typically require
    about 0.8 byte per pixel to store it at very highest JPEG quality.
    Most other subjects take less.

    It is rare to see an image from a 6MP Bayer mask camera that needs
    5Mbyte to encode as JPEG 2x1 subsampled,

    Martin Brown
    Martin Brown, Mar 22, 2007
  17. Caien

    Signal Guest

    Perhaps because you've experienced cameras that are spec-impressive
    for marketing purposes, but not well designed or optimized to use that
    censor properly. Perhaps even the lens is the limiting factor? A
    commercial photographer friend uses a 48 megapixel tri-linear CCD
    sensor back, and the results are awesome.
    Signal, Mar 22, 2007
  18. Caien

    Signal Guest

    "David J Taylor"
    On a monitor screen.
    Signal, Mar 22, 2007
  19. Caien

    Signal Guest

    Maybe it's that, or a combination of the two. Certainly looked like
    typical JPEG artifacts to me, but I'll try to post some samples for a
    second opinion.

    The white balance feature on this camera is garbage, so I have to do
    that post. Do you think it's better to do this on RAW images, or is it
    OK to do with with JPEG?
    Is there any difference in algorithms used for JPEG compression, or is
    there one standard algorithm that all applications and hardware use?
    Signal, Mar 22, 2007
  20. Caien

    Scott W Guest

    White balcance is far easier to adjust with a raw file compared to
    working on the jpeg file. And if the color balance if very far out it
    and be all but imposible to get it back using just the jpeg file.

    There are differences in how the JPEG compression is done. I bought a
    program called Advanced JPEG Compressor which gives you way more
    control in how an image gets compressed. There are a lot of parameters
    that can be adjusted to tune how the compression is done and what you
    are after.

    Scott W, Mar 22, 2007
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.