JPEG degradation

Discussion in 'Digital Photography' started by TSKO, Jan 26, 2007.

  1. Paranoid is good. In some circumstances perhaps it's not necessary --
    but it's always valid, and it saves worrying about the behavior of
    individual programs in that regard. It's good test design.
     
    David Dyer-Bennet, Jan 28, 2007
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  2. Seems like the server had performance problems and prioritized html
    over images. I've forced a restart, but the same might happen again.
    If so, I apologize for the inconvenience and will try to fix the
    problem for good.
     
    Toke Eskildsen, Jan 28, 2007
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  3. In using Picasa2, the original image is retained even when a copy is
    edited. So, deleting the editing reverts to the original image with no
    loss or degradation. That is the beauty of Picasa2.

    Morton Linder
     
    Morton Linder, Jan 28, 2007
  4. I think iPhoto is like that too.
     
    Paul D. Sullivan, Jan 28, 2007
  5. TSKO

    John Turco Guest


    Hello, ASAAR:

    I always compose (and proofread) my e-mail and Usenet messages, very
    carefuly, offline. Take your time, what's the rush? :-J


    Cordially,
    John Turco <>
     
    John Turco, Jan 29, 2007
  6. TSKO

    John Turco Guest


    Hello, David:

    Oh, "from memory," eh? You're a punster, and didn't even know it. :p


    Cordially,
    John Turco <>
     
    John Turco, Jan 29, 2007
  7. TSKO

    John Turco Guest


    Hello, ASAAR:

    Why don't you two, old codgers simply kiss and make up? <g>


    Cordially,
    John Turco <>
     
    John Turco, Jan 29, 2007
  8. TSKO

    ASAAR Guest

    I'm willing. He can kiss my . . . uh, never mind. <g>
     
    ASAAR, Jan 29, 2007
  9. Better than being a poet, anyway.
     
    David Dyer-Bennet, Jan 29, 2007
  10. TSKO

    dj_nme Guest

    If you save an edited copy (eg: using the "save as" command with a
    different file name), then by definition the original file still exists
    in an unaltered condition.
    It's only if you just save (hitting the "save" button) the edited image
    back onto the original (and effectively destroy it) does editing alter
    the original.
     
    dj_nme, Jan 29, 2007
  11. I think we shall have to agree to differ on the point of whether it's
    "foolish" to keep a copy of the original compressed image in case the user
    decides to re-save. There's a difference between saving a file you've not
    changed at all (agreed, there's not a lot of point in that) and saving a
    file in which you have changed some stuff but, importantly, not the actual
    image data. That's often quite a useful and sensible thing to do.

    I don't have a "protect the users from themselves" philosophy. I keep the
    original image data because I personally make frequent changes to image
    files which have no impact on the image data itself and I'd rather not have
    my image degraded when I make those changes. I've yet to experience any
    disk thrashing as a result. Indeed I doubt it would prove an issue because
    the compressed data is only accessed twice - when you first read it and
    again if and when you decide to re-save without changing the image.
    I don't really want to get into a war of words about how useful or otherwise
    my application is. It's useful to me and that's my only design criterion.
    I offer it on the web because it has some features which others might find
    useful and there are a small number of people who have indeed found it
    useful. If you're not one of them then that's fine. No one is asking you
    to use it.

    Seeing as you've asked, it is limited to the extent that it doesn't attempt
    to be a photo editor. There are commercial packages which do that far
    better than I could ever expect to because I don't have the basic grounding
    in image processing technology. I have therefore concentrated on the more
    administrative tasks such as manipulating EXIF data.

    I have heard good reports of Irfanview and have no doubt that it's an
    excellent piece of software. I've never used it myself because I've never
    felt the need. No doubt many of the things my software does can also be
    done by Irfanview but that's not the point. I implemented my own as a
    training excercise and because I enjoy doing that sort of thing. Whether or
    not there are other packages around which do the same is really of no
    consequence.

    I say the licence features may vary from time to time because this isn't a
    commercial exercise and I don't want to be beholden to anyone when it comes
    to deciding what to put into my software. The way it works is that most
    features are free forever and a small number are only free for thirty days -
    by which time you should have been able to decide for yourself whether they
    were sufficiently useful to you to be worth a token one-off payment.

    I wasn't really intending to advertise my wares in this thread. I posted
    the web address purely to use my own application as a evidence in support of
    the claim that it isn't compulsory to recompress an image every time you
    save it.

    Regards
    Keith
     
    Keith Sheppard, Jan 29, 2007
  12. TSKO

    ASAAR Guest

    You're being overly sensitive. I'm used to authors providing at
    least general descriptions of what their software can be used for.
    What I've never seen until now is software that must first be
    downloaded and used before one would know if it is able to do what
    one might want. This has nothing to do with whether your software
    is useful or not. I'm sure that it is very useful for what you
    designed it to do. But I don't know what it can do so there's no
    way I can know whether it *I* might also find it useful. Guessing
    that I might not find it useful and closing with a snippy "No one is
    asking you to use it" pretty much guarantees that I won't, which
    appears to be what you want. So we both walk away happy.
     
    ASAAR, Jan 29, 2007
  13. You're being overly sensitive.
    You're probably right and if so, I apologise.

    Just for the record, what I've tended to do with my software is to recommend
    it to anyone who has a specific problem which I think my application may be
    able to solve. It's not exactly my flagship product and I don't have the
    time or inclination (and probably not the skill) to enhance it to the point
    where it would be a serious competitor to the likes of Irfanview or
    whatever. It's therefore been shunted into a siding and the lack of
    information on the web page probably reflects its status.
    OK, I think we've done this one to death. I'm on my way ;)

    Regards
    Keith
     
    Keith Sheppard, Jan 30, 2007
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