how to stop JPEG loss

Discussion in 'Digital Photography' started by drs@canby.com, Nov 18, 2004.

  1. Guest

    Is there an easy way to lock a jpeg file so it doesn't lose data when
    it's viewed multiple times? I don't have PhotoShop or any similar
    programs. Simply changing the filename won't prevent loss, will it?
    , Nov 18, 2004
    #1
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  2. Just viewing a jpeg file will not cause any loss. You're just reading the
    file when viewing, not modifying it. It's only when the file is changed,
    such as when using Photoshop.

    Don

    <> wrote in message
    news:...
    > Is there an easy way to lock a jpeg file so it doesn't lose data when
    > it's viewed multiple times? I don't have PhotoShop or any similar
    > programs. Simply changing the filename won't prevent loss, will it?
    Donald Patrylow, Nov 18, 2004
    #2
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  3. Mark² Guest

    <> wrote in message
    news:...
    > Is there an easy way to lock a jpeg file so it doesn't lose data when
    > it's viewed multiple times? I don't have PhotoShop or any similar
    > programs. Simply changing the filename won't prevent loss, will it?


    You can open it, copy it, re-name it, and view it a million times, and it
    will NOT lose anything. Nothing at all.

    The ONLY thing that will change/lose data from the image is when you alter
    it within a program designed for image manipulation, or save over the top of
    itself within such a program...or re-size it, etc.

    Simply viewing it or copying it to other folders, etc. will not damage it in
    any way.

    If you want to be able to make changes to the image without degrading it,
    simply convert it to a .tif or other uncompressed file format.
    Mark², Nov 18, 2004
    #3
  4. Ron Hunter Guest

    wrote:
    > Is there an easy way to lock a jpeg file so it doesn't lose data when
    > it's viewed multiple times? I don't have PhotoShop or any similar
    > programs. Simply changing the filename won't prevent loss, will it?


    Sigh.

    One more time

    VIEWING A JPG PHOTO DOES NOT, REPEAT; NOT, degrade quality, only
    repeated editing and saves degrade quality. You can view the photo a
    million times and it will display the same each time.
    Ron Hunter, Nov 18, 2004
    #4
  5. Peter Corser Guest

    Ron

    Perfectly right and I agree with the sentiments wholeheartedly, but maybe we
    should also stress not saving the file - an involuntary user action within
    the viewing software (dependant on the software) could conceivably cause the
    software to ask if you want to save the file. Answering yes (which a new
    user may well do) would generate the problem.

    Peter
    --
    Peter & Elizabeth Corser
    Leighton Buzzard
    Beds UK
    "Ron Hunter" <> wrote in message
    news:...
    > wrote:
    >> Is there an easy way to lock a jpeg file so it doesn't lose data when
    >> it's viewed multiple times? I don't have PhotoShop or any similar
    >> programs. Simply changing the filename won't prevent loss, will it?

    >
    > Sigh.
    >
    > One more time
    >
    > VIEWING A JPG PHOTO DOES NOT, REPEAT; NOT, degrade quality, only repeated
    > editing and saves degrade quality. You can view the photo a million times
    > and it will display the same each time.
    Peter Corser, Nov 18, 2004
    #5
  6. Tony Guest

    Simply close the file without saving. The jpeg will remain exactly as it
    was.

    --
    http://www.chapelhillnoir.com
    home of The Camera-ist's Manifesto
    The Improved Links Pages are at
    http://www.chapelhillnoir.com/links/mlinks00.html
    A sample chapter from "Haight-Ashbury" is at
    http://www.chapelhillnoir.com/writ/hait/hatitl.html

    <> wrote in message
    news:...
    > Is there an easy way to lock a jpeg file so it doesn't lose data when
    > it's viewed multiple times? I don't have PhotoShop or any similar
    > programs. Simply changing the filename won't prevent loss, will it?
    Tony, Nov 18, 2004
    #6
  7. Guest

    First, let me said I don't know what I'm talking about. But I've been
    told by folks who know more than I that opening and closing jpegs will
    change the data. One sent me this link this morning:
    http://www.pixelp.com/watches/ps-tips/



    On Wed, 17 Nov 2004 23:18:55 -0500, "Donald Patrylow"
    <> wrote:

    >Just viewing a jpeg file will not cause any loss. You're just reading the
    >file when viewing, not modifying it. It's only when the file is changed,
    >such as when using Photoshop.
    >
    >Don
    >
    ><> wrote in message
    >news:...
    >> Is there an easy way to lock a jpeg file so it doesn't lose data when
    >> it's viewed multiple times? I don't have PhotoShop or any similar
    >> programs. Simply changing the filename won't prevent loss, will it?

    >
    , Nov 18, 2004
    #7
  8. Marcel Guest

    Sure, but unless I'm out to lunch, the guy says repeatedly:
    2. open (1) and save as a JEPG
    3. open (2) and save as a JEPG etc..
    In fact the pic has been saved 5 times if I can count... or did I miss
    something?
    Marcel

    <> wrote in message
    news:...
    > First, let me said I don't know what I'm talking about. But I've been
    > told by folks who know more than I that opening and closing jpegs will
    > change the data. One sent me this link this morning:
    > http://www.pixelp.com/watches/ps-tips/
    >
    >
    >
    > On Wed, 17 Nov 2004 23:18:55 -0500, "Donald Patrylow"
    > <> wrote:
    >
    > >Just viewing a jpeg file will not cause any loss. You're just reading

    the
    > >file when viewing, not modifying it. It's only when the file is changed,
    > >such as when using Photoshop.
    > >
    > >Don
    > >
    > ><> wrote in message
    > >news:...
    > >> Is there an easy way to lock a jpeg file so it doesn't lose data when
    > >> it's viewed multiple times? I don't have PhotoShop or any similar
    > >> programs. Simply changing the filename won't prevent loss, will it?

    > >

    >
    Marcel, Nov 18, 2004
    #8
  9. Guest

    On Thu, 18 Nov 2004 11:24:15 -0500, "Marcel" <>
    wrote:

    >Sure, but unless I'm out to lunch, the guy says repeatedly:
    >2. open (1) and save as a JEPG
    >3. open (2) and save as a JEPG etc..
    >In fact the pic has been saved 5 times if I can count... or did I miss
    >something?
    >Marcel


    Is that different than simply opening and closing it? Doesn't that
    automatically save it again as a JPEG?
    , Nov 18, 2004
    #9
  10. Jim Townsend Guest

    wrote:

    > First, let me said I don't know what I'm talking about. But I've been
    > told by folks who know more than I that opening and closing jpegs will
    > change the data. One sent me this link this morning:
    > http://www.pixelp.com/watches/ps-tips/
    >


    Closing a jpeg is not SAVING it.. (ie Click on 'File' -> 'Save')

    It says SAVEing JPEGS in the URL you've shown, not closing JPEGS.

    Saving is what causes the degradation because the lossy compression
    takes place during the SAVE.

    Consider the internet.. Every time someone accesses a web site with
    jpeg images, the images are are opened by the hosts HTTP server which
    then transmits them to the client who views them on his/her browser.

    Some sites get *millions* of hits per year. Despite being opened and
    closed MILLIONS of times, the jpeg images are unchanged.

    It would be a nightmare if webmasters had to constantly replace their
    'worn out' jpegs on a regular basis because they were viewed too much :)
    Jim Townsend, Nov 18, 2004
    #10
  11. Ken Weitzel Guest

    wrote:
    > On Thu, 18 Nov 2004 11:24:15 -0500, "Marcel" <>
    > wrote:
    >
    >
    >>Sure, but unless I'm out to lunch, the guy says repeatedly:
    >>2. open (1) and save as a JEPG
    >>3. open (2) and save as a JEPG etc..
    >>In fact the pic has been saved 5 times if I can count... or did I miss
    >>something?
    >>Marcel

    >
    >
    > Is that different than simply opening and closing it? Doesn't that
    > automatically save it again as a JPEG?


    Hi...

    Maybe the problem is with the word "close" ?

    Open it, look at it, and "stop looking at it" equals
    no change. No harm done, no loss of quality.

    Open it, look at it, change it somehow, and
    "save" it; or "save it as" and there is harm
    done, a loss of quality.

    Ken
    Ken Weitzel, Nov 18, 2004
    #11
  12. Guest

    On Thu, 18 Nov 2004 16:49:19 GMT, Ken Weitzel <>
    wrote:

    >
    >Maybe the problem is with the word "close" ?
    >
    >Open it, look at it, and "stop looking at it" equals
    >no change. No harm done, no loss of quality.
    >
    >Open it, look at it, change it somehow, and
    >"save" it; or "save it as" and there is harm
    >done, a loss of quality.
    >
    >Ken


    Ken and all: Thanks for the clarification. I'm sort of disappointed I
    didn't know that. Oh, well...
    , Nov 18, 2004
    #12
  13. YAG-ART Guest

    On Thu, 18 Nov 2004 08:36:22 -0800, wrote:

    >On Thu, 18 Nov 2004 11:24:15 -0500, "Marcel" <>
    >wrote:
    >
    >>Sure, but unless I'm out to lunch, the guy says repeatedly:
    >>2. open (1) and save as a JEPG
    >>3. open (2) and save as a JEPG etc..
    >>In fact the pic has been saved 5 times if I can count... or did I miss
    >>something?
    >>Marcel

    >
    >Is that different than simply opening and closing it? Doesn't that
    >automatically save it again as a JPEG?



    No it doen't save it again. Opening it puts the image into RAM,
    closing the image flushes the image out of RAM, and has no effect on
    the image on the disk
    YAG-ART, Nov 18, 2004
    #13
  14. Marcel Guest

    Simply closing it without having done anything will not save it again.
    However, see below, he says "save it as JPEG". This in fact is saving.
    Marcel

    <> wrote in message
    news:...
    > On Thu, 18 Nov 2004 11:24:15 -0500, "Marcel" <>
    > wrote:
    >
    > >Sure, but unless I'm out to lunch, the guy says repeatedly:
    > >2. open (1) and save as a JEPG
    > >3. open (2) and save as a JEPG etc..
    > >In fact the pic has been saved 5 times if I can count... or did I miss
    > >something?
    > >Marcel

    >
    > Is that different than simply opening and closing it? Doesn't that
    > automatically save it again as a JPEG?
    Marcel, Nov 18, 2004
    #14
  15. Jim Townsend <> wrote let it be known in
    news::

    > It would be a nightmare if webmasters had to constantly
    > replace their 'worn out' jpegs on a regular basis because
    > they were viewed too much :)


    I insist on regular jpeg scheduled maintenance from whichever
    web server I host on.

    The owners manual usually suggests a pixel change every 300
    views or 3 days, whichever comes first, and a 'rotate and color
    balance' every 20,000 views.

    --
    Christina Barnes
    CB Design
    Christina Barnes, Nov 18, 2004
    #15
  16. Ron Hunter wrote:
    > wrote:
    >
    >> Is there an easy way to lock a jpeg file so it doesn't lose data when
    >> it's viewed multiple times? I don't have PhotoShop or any similar
    >> programs. Simply changing the filename won't prevent loss, will it?

    >
    >
    > Sigh.
    >
    > One more time
    >
    > VIEWING A JPG PHOTO DOES NOT, REPEAT; NOT, degrade quality, only
    > repeated editing and saves degrade quality. You can view the photo a
    > million times and it will display the same each time.


    This is clear to me. Thank you.
    One additional question though - I might open an original jpg/jpeg
    file,
    (named say file01_d0.jpg) edit (rotate, crop, brighten, contrast, etc.),
    then
    save the result as a jpg to a different file name (file01_d1.) Doing this
    once might degrade quality an acceptably ignorable amount (depending
    on one's preference and ultimate use.) The original file should remain
    unchanged.
    Opening the new file and further editting repeatedly ought to continue to
    degrade quality - to a possibly unacceptable result.

    Is there a limit to how much such a process will degrade? I tried
    some of
    this on both a tif and jpg version of the same image. Using the minimum
    allowable compression for the jpg. I did this until my fingers got tired,
    and as long as I did not change the image size, each subsequent file size
    did not change and I could not see any degradation in quality in the jpg
    series.

    Indeed the only times I saw the file size change was opening a tif that
    had a large area of say, all blue sky, then save as jpg. In this case
    the file size dropped noticabely. If the image was very complex - no
    large smooth areas, every pixel was weirdly different than the ones around
    it, the resulting jpg file size did not go down much at all.
    Alternatively when I did a series of sequentially saving filea to jpg with
    a compression of greater than zero - any larger number (10% - 50% ...)
    really tore the image to mush quickly. First time I saw this, I never
    again
    let that compression value be anything but zero.
    Does saving sequential jpg _always_ lose resolution in all cases?
    Even when no compression is selected?

    Or does it depend on the image manipulation software being used?

    Thanks,
    Bill H.
    William H. Hathaway, Nov 18, 2004
    #16
  17. Harvey Guest

    "Christina Barnes" <Christina(dot)> wrote in message
    news:Xns95A5800C884BA123eieio@216.196.97.142...
    > Jim Townsend <> wrote let it be known in
    > news::
    >
    >> It would be a nightmare if webmasters had to constantly
    >> replace their 'worn out' jpegs on a regular basis because
    >> they were viewed too much :)

    >
    > I insist on regular jpeg scheduled maintenance from whichever
    > web server I host on.
    >
    > The owners manual usually suggests a pixel change every 300
    > views or 3 days, whichever comes first, and a 'rotate and color
    > balance' every 20,000 views.
    >
    > --
    > Christina Barnes
    > CB Design


    I don't know weather to laugh or cry... or perhaps I should just go and
    spend the next few hours doing a 'rotate and color balance' on all the
    jpeg's I have..

    ....it'll give me something to do I suppose.
    Harvey, Nov 18, 2004
    #17
  18. Ken Weitzel Guest

    Harvey wrote:
    > "Christina Barnes" <Christina(dot)> wrote in message
    > news:Xns95A5800C884BA123eieio@216.196.97.142...
    >
    >>Jim Townsend <> wrote let it be known in
    >>news::
    >>
    >>
    >>>It would be a nightmare if webmasters had to constantly
    >>>replace their 'worn out' jpegs on a regular basis because
    >>>they were viewed too much :)

    >>
    >>I insist on regular jpeg scheduled maintenance from whichever
    >>web server I host on.
    >>
    >>The owners manual usually suggests a pixel change every 300
    >>views or 3 days, whichever comes first, and a 'rotate and color
    >>balance' every 20,000 views.
    >>
    >>--
    >>Christina Barnes
    >>CB Design

    >
    >
    > I don't know weather to laugh or cry... or perhaps I should just go and
    > spend the next few hours doing a 'rotate and color balance' on all the
    > jpeg's I have..
    >
    > ...it'll give me something to do I suppose.


    That's not necessary if you're using the new
    synthetic pixels. You can go up to twice as
    long; provided you change the filter once every
    300 or 400 viewings. And you'll need a grease
    job as recommended by the viewer manufacturer.

    Ken
    Ken Weitzel, Nov 18, 2004
    #18
  19. Ron Hunter Guest

    wrote:
    > On Thu, 18 Nov 2004 11:24:15 -0500, "Marcel" <>
    > wrote:
    >
    >
    >>Sure, but unless I'm out to lunch, the guy says repeatedly:
    >>2. open (1) and save as a JEPG
    >>3. open (2) and save as a JEPG etc..
    >>In fact the pic has been saved 5 times if I can count... or did I miss
    >>something?
    >>Marcel

    >
    >
    > Is that different than simply opening and closing it? Doesn't that
    > automatically save it again as a JPEG?


    Not unless your program is totally braindead!
    Ron Hunter, Nov 18, 2004
    #19
  20. Aerticeus Guest

    There is IMHO a difference between view and save

    Maybe the programers should have a View listing rather than rely on Open?

    Aerticeus

    "Ron Hunter" <> wrote in message
    news:...
    > wrote:
    >> On Thu, 18 Nov 2004 11:24:15 -0500, "Marcel" <>
    >> wrote:
    >>
    >>
    >>>Sure, but unless I'm out to lunch, the guy says repeatedly:
    >>>2. open (1) and save as a JEPG
    >>>3. open (2) and save as a JEPG etc..
    >>>In fact the pic has been saved 5 times if I can count... or did I miss
    >>>something?
    >>>Marcel

    >>
    >>
    >> Is that different than simply opening and closing it? Doesn't that
    >> automatically save it again as a JPEG?

    >
    > Not unless your program is totally braindead!
    Aerticeus, Nov 18, 2004
    #20
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