JPEG Questions: Loss In Quality When "Saving"

Discussion in 'Digital Photography' started by Xtx99, Apr 8, 2004.

  1. Xtx99

    Xtx99 Guest

    I'm confused about quality deterioration when repeatedly opening and
    "saving" JPEG images. I've read that every time a JPEG image is "saved," some
    quality is lost due to the lossy compression format.
    My questions are....

    1) What is meant by "saving" a JPEG image?

    2) If I simply "open" a JPEG image in Microsoft Photo Editor, Adobe Photoshop
    CS or any other image editor, View the JPEG image and then simply exit out of
    viewing the JPEG, am I actually "saving" it again and therefore loosing
    quality?

    3) If in Windows I right click on a JPEG and make a duplicate copy of the
    JPEG, is the copy (with a different name) "saved" and therefore the quality of
    the copy diminished.

    4) If I open a JPEG in a photo editor and "save as" (instead of simply
    exiting) and use the same name as the JPEG I just opened, is the quality
    diminished?

    When I do all of the above things, I don't notice any decrease in
    quality and the JPEG seems to be exactly the same size so I'm guessing I
    haven't degraded the original. If I'm wrong, I'm guessing I should make each
    JPEG file "read only" or burn them to a CD or DVD so they can't be changed when
    I view them.

    If I open up a JPEG in a photo editing program and make any changes to
    the JPEG at all, I can understand that the quality degrades. Any advice on my
    questions are appreciated.
    Xtx99, Apr 8, 2004
    #1
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  2. Xtx99

    Tom Thackrey Guest

    On 7-Apr-2004, (Xtx99) wrote:

    > I'm confused about quality deterioration when repeatedly opening
    > and
    > "saving" JPEG images. I've read that every time a JPEG image is "saved,"
    > some
    > quality is lost due to the lossy compression format.
    > My questions are....
    >
    > 1) What is meant by "saving" a JPEG image?


    In the context of degrading the image, saving means compressing the image.

    >
    > 2) If I simply "open" a JPEG image in Microsoft Photo Editor, Adobe
    > Photoshop
    > CS or any other image editor, View the JPEG image and then simply exit out
    > of
    > viewing the JPEG, am I actually "saving" it again and therefore loosing
    > quality?


    NO

    >
    > 3) If in Windows I right click on a JPEG and make a duplicate copy of the
    > JPEG, is the copy (with a different name) "saved" and therefore the
    > quality of
    > the copy diminished.


    NO

    >
    > 4) If I open a JPEG in a photo editor and "save as" (instead of simply
    > exiting) and use the same name as the JPEG I just opened, is the quality
    > diminished?
    >


    It depends on the editor. Some, if you have made no changes or even if
    you've rotated the image, are smart enough not to recompress. Some aren't
    that smart.

    > When I do all of the above things, I don't notice any decrease in
    > quality and the JPEG seems to be exactly the same size so I'm guessing I
    > haven't degraded the original.


    if the size is exactly the same, odds are the file was not recompressed.

    >If I'm wrong, I'm guessing I should make
    > each
    > JPEG file "read only" or burn them to a CD or DVD so they can't be changed
    > when
    > I view them.
    >
    > If I open up a JPEG in a photo editing program and make any changes
    > to
    > the JPEG at all, I can understand that the quality degrades. Any advice
    > on my
    > questions are appreciated.


    As I mentioned, some editors can do lossless rotation on jpegs. Most edits
    require recompression which will degrade the quality.



    --
    Tom Thackrey
    www.creative-light.com
    tom (at) creative (dash) light (dot) com
    do NOT send email to (it's reserved for spammers)
    Tom Thackrey, Apr 8, 2004
    #2
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  3. Xtx99

    Guest

    Xtx99 <> wrote:
    > I'm confused about quality deterioration when repeatedly opening and
    > "saving" JPEG images. I've read that every time a JPEG image is "saved," some
    > quality is lost due to the lossy compression format.
    > My questions are....


    > 1) What is meant by "saving" a JPEG image?


    Anything that records the image file to disk for later retrieval, such as shooting
    the image in the first place, as well as editting and than saving the image.

    > 2) If I simply "open" a JPEG image in Microsoft Photo Editor, Adobe Photoshop
    > CS or any other image editor, View the JPEG image and then simply exit out of
    > viewing the JPEG, am I actually "saving" it again and therefore loosing
    > quality?


    No, you save the image when you go to "file->save" or "file->save as".

    > 3) If in Windows I right click on a JPEG and make a duplicate copy of the
    > JPEG, is the copy (with a different name) "saved" and therefore the quality of
    > the copy diminished.


    Good question. I just tried a little test. I took a photo in a file called
    DSFC0010.JPG and copied it to "DSCF0010 copy.JPG" on my Mac which is running
    Mac OS X 10.3.3 and then I compared the sizes:

    picard:~/Desktop stan$ ls -l *.JPG
    -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010 copy.JPG
    -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010.JPG

    As you can see, the sizes of these two files are identical. I also ran a diff
    against the two files and found no differences between the two.

    picard:~/Desktop stan$ diff DSCF0010.JPG "DSCF0010 copy.JPG"
    picard:~/Desktop stan$

    So it looks like the answer to your question is no.

    > 4) If I open a JPEG in a photo editor and "save as" (instead of simply
    > exiting) and use the same name as the JPEG I just opened, is the quality
    > diminished?


    I opened the same DSCF0010.JPG in a rudimentary editor on my Mac and then
    clicked "Save as" and saved the file under the name "DSCF0010 copy 2.JPG"
    and then I opened up "DSCF0010 copy 2.JPG" in the same editor and saved
    it under the name "DSCF0010 copy 3.JPG" and here's what happens when I
    view a list of those four files:

    picard:~/Desktop stan$ ls -l *.JPG
    -rw-r--r-- 1 stan wheel 96854 9 Apr 09:46 DSCF0010 copy 2.JPG
    -rw-r--r-- 1 stan wheel 96900 9 Apr 09:48 DSCF0010 copy 3.JPG
    -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010 copy.JPG
    -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010.JPG
    picard:~/Desktop stan$ diff "DSCF0010 copy 2.JPG" "DSCF0010 copy 3.JPG"
    Binary files DSCF0010 copy 2.JPG and DSCF0010 copy 3.JPG differ
    picard:~/Desktop stan$

    As you can see, I also did a diff. So it looks like the claims that saving a
    jpg file again does result in a loss of quality, assuming that smaller size is
    an indicator of a quality loss. What I do not understand is why the save the file
    "DSCF0010 copy 3.JPG" is slightly larger than the "DSCF0010 copy 3.JPG" file.

    > When I do all of the above things, I don't notice any decrease in
    > quality and the JPEG seems to be exactly the same size so I'm guessing I
    > haven't degraded the original. If I'm wrong, I'm guessing I should make each
    > JPEG file "read only" or burn them to a CD or DVD so they can't be changed when
    > I view them.


    Are you sure? Can you reproduce some examples, as I did in this followup msg?

    > If I open up a JPEG in a photo editing program and make any changes to
    > the JPEG at all, I can understand that the quality degrades. Any advice on my
    > questions are appreciated.


    Its simply a matter of compressing more and more each time, I suppose.
    , Apr 9, 2004
    #3
  4. wrote in message news:<c569rn$k1k$>...
    > > 3) If in Windows I right click on a JPEG and make a duplicate copy of the
    > > JPEG, is the copy (with a different name) "saved" and therefore the quality of
    > > the copy diminished.

    >
    > Good question. I just tried a little test. I took a photo in a file called
    > DSFC0010.JPG and copied it to "DSCF0010 copy.JPG" on my Mac which is running
    > Mac OS X 10.3.3 and then I compared the sizes:
    >
    > picard:~/Desktop stan$ ls -l *.JPG
    > -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010 copy.JPG
    > -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010.JPG
    >
    > As you can see, the sizes of these two files are identical. I also ran a diff
    > against the two files and found no differences between the two.


    Imagine that, copying a file copies the file.

    > picard:~/Desktop stan$ diff DSCF0010.JPG "DSCF0010 copy.JPG"
    > picard:~/Desktop stan$
    >
    > So it looks like the answer to your question is no.
    >
    > > 4) If I open a JPEG in a photo editor and "save as" (instead of simply
    > > exiting) and use the same name as the JPEG I just opened, is the quality
    > > diminished?

    >
    > I opened the same DSCF0010.JPG in a rudimentary editor on my Mac and then
    > clicked "Save as" and saved the file under the name "DSCF0010 copy 2.JPG"
    > and then I opened up "DSCF0010 copy 2.JPG" in the same editor and saved
    > it under the name "DSCF0010 copy 3.JPG" and here's what happens when I
    > view a list of those four files:
    >
    > picard:~/Desktop stan$ ls -l *.JPG
    > -rw-r--r-- 1 stan wheel 96854 9 Apr 09:46 DSCF0010 copy 2.JPG
    > -rw-r--r-- 1 stan wheel 96900 9 Apr 09:48 DSCF0010 copy 3.JPG
    > -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010 copy.JPG
    > -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010.JPG
    > picard:~/Desktop stan$ diff "DSCF0010 copy 2.JPG" "DSCF0010 copy 3.JPG"
    > Binary files DSCF0010 copy 2.JPG and DSCF0010 copy 3.JPG differ
    > picard:~/Desktop stan$
    >
    > As you can see, I also did a diff. So it looks like the claims that saving a
    > jpg file again does result in a loss of quality, assuming that smaller size is
    > an indicator of a quality loss. What I do not understand is why the save the file
    > "DSCF0010 copy 3.JPG" is slightly larger than the "DSCF0010 copy 3.JPG" file.


    Often times the size will stay the same or even go up on the second or
    third JPEGing, and the unique color count will skyrocket. This is of
    course a disaster from an optical perspective, since all the new
    unique colors are statistical noise.

    JPEG should never, ever be used if you care about an image in the
    slightest, especially if you potentially might retouch/crop it.
    George Preddy, Apr 10, 2004
    #4
  5. Xtx99

    John Navas Guest

    [POSTED TO rec.photo.digital - REPLY ON USENET PLEASE]

    In <> on 9 Apr 2004 22:46:44
    -0700, (George Preddy) wrote:

    > wrote in message news:<c569rn$k1k$>...


    >> picard:~/Desktop stan$ ls -l *.JPG
    >> -rw-r--r-- 1 stan wheel 96854 9 Apr 09:46 DSCF0010 copy 2.JPG
    >> -rw-r--r-- 1 stan wheel 96900 9 Apr 09:48 DSCF0010 copy 3.JPG
    >> -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010 copy.JPG
    >> -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010.JPG
    >> picard:~/Desktop stan$ diff "DSCF0010 copy 2.JPG" "DSCF0010 copy 3.JPG"
    >> Binary files DSCF0010 copy 2.JPG and DSCF0010 copy 3.JPG differ
    >> picard:~/Desktop stan$
    >>
    >> As you can see, I also did a diff. So it looks like the claims that saving a
    >> jpg file again does result in a loss of quality, assuming that smaller size is
    >> an indicator of a quality loss. What I do not understand is why the save the file
    >> "DSCF0010 copy 3.JPG" is slightly larger than the "DSCF0010 copy 3.JPG" file.

    >
    >Often times the size will stay the same or even go up on the second or
    >third JPEGing, and the unique color count will skyrocket. This is of
    >course a disaster from an optical perspective, since all the new
    >unique colors are statistical noise.


    Nonsense.

    >JPEG should never, ever be used if you care about an image in the
    >slightest, especially if you potentially might retouch/crop it.


    Rubbish.

    --
    Best regards,
    John Navas <http://navasgrp.home.att.net/>

    "A little learning is a dangerous thing." [Alexander Pope]
    "It is better to sit in silence and appear ignorant,
    than to open your mouth and remove all doubt." [Mark Twain]
    John Navas, Apr 10, 2004
    #5
  6. John Navas <> wrote in message news:<ooNdc.4922$>...
    > [POSTED TO rec.photo.digital - REPLY ON USENET PLEASE]
    >
    > In <> on 9 Apr 2004 22:46:44
    > -0700, (George Preddy) wrote:
    >
    > > wrote in message news:<c569rn$k1k$>...

    >
    > >> picard:~/Desktop stan$ ls -l *.JPG
    > >> -rw-r--r-- 1 stan wheel 96854 9 Apr 09:46 DSCF0010 copy 2.JPG
    > >> -rw-r--r-- 1 stan wheel 96900 9 Apr 09:48 DSCF0010 copy 3.JPG
    > >> -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010 copy.JPG
    > >> -rw-r--r-- 1 stan stan 171869 2 Sep 2001 DSCF0010.JPG
    > >> picard:~/Desktop stan$ diff "DSCF0010 copy 2.JPG" "DSCF0010 copy 3.JPG"
    > >> Binary files DSCF0010 copy 2.JPG and DSCF0010 copy 3.JPG differ
    > >> picard:~/Desktop stan$
    > >>
    > >> As you can see, I also did a diff. So it looks like the claims that saving a
    > >> jpg file again does result in a loss of quality, assuming that smaller size is
    > >> an indicator of a quality loss. What I do not understand is why the save the file
    > >> "DSCF0010 copy 3.JPG" is slightly larger than the "DSCF0010 copy 3.JPG" file.

    > >
    > >Often times the size will stay the same or even go up on the second or
    > >third JPEGing, and the unique color count will skyrocket. This is of
    > >course a disaster from an optical perspective, since all the new
    > >unique colors are statistical noise.

    >
    > Nonsense.


    Oh, I forgot to mention that only for you lossy JPEG is lossless.

    > >JPEG should never, ever be used if you care about an image in the
    > >slightest, especially if you potentially might retouch/crop it.

    >
    > Rubbish.


    Your standardds are in the dirt.
    George Preddy, Apr 10, 2004
    #6
  7. Xtx99

    Guest

    George Preddy <> wrote:

    > Often times the size will stay the same or even go up on the second or
    > third JPEGing, and the unique color count will skyrocket. This is of
    > course a disaster from an optical perspective, since all the new
    > unique colors are statistical noise.


    > JPEG should never, ever be used if you care about an image in the
    > slightest, especially if you potentially might retouch/crop it.


    I disagree. I shoot exclusively jpeg; mostly landscape and other outdoor
    scenes. I get spectacular results with max resolution jpeg files from my
    Digital Rebel and my previous camera (Minolta S414). I always modify my
    images in Photoshop 7 before printing them. I have seen a number of
    printed comparisons between printed raw and printed jpg files. At best,
    the difference in quality and detail has been extremely minimal and
    in most of the comparisons, most people would be hard pressed to see
    any difference at all, unless maybe they viewed the images under a
    magnefying glass. Raw is nice, but I do not have the time to wait for
    the large files to save each time I shap my camera's shutter and I do
    not have the memory capacity to handle two or three hundred raw images
    at a time while I am out shooting photos.
    , Apr 10, 2004
    #7
  8. Xtx99

    John Navas Guest

    [POSTED TO rec.photo.digital - REPLY ON USENET PLEASE]

    In <> on 10 Apr 2004 07:17:11
    -0700, (George Preddy) wrote:

    >John Navas <> wrote in message news:<ooNdc.4922$>...


    >> >Often times the size will stay the same or even go up on the second or
    >> >third JPEGing, and the unique color count will skyrocket. This is of
    >> >course a disaster from an optical perspective, since all the new
    >> >unique colors are statistical noise.

    >>
    >> Nonsense.

    >
    >Oh, I forgot to mention that only for you lossy JPEG is lossless.


    No, just essentially indistinguishable from the original (with good
    high-quality compression), as I proved in
    <http://groups.google.com/groups?selm=PrC9c.2326$>.
    You still haven't taken my bet, so that would seem to put the matter to rest
    (for the rest of us at least -- you never seem to rest:).

    >> >JPEG should never, ever be used if you care about an image in the
    >> >slightest, especially if you potentially might retouch/crop it.

    >>
    >> Rubbish.

    >
    >Your standardds are in the dirt.


    My standards are based on hard evidence. Yours are hot air.

    --
    Best regards,
    John Navas
    [PLEASE NOTE: Ads belong *only* in rec.photo.marketplace.digital, as per
    <http://bobatkins.photo.net/info/charter.htm> <http://rpdfaq.50megs.com/>]
    John Navas, Apr 10, 2004
    #8
  9. John Navas <> wrote in message news:<AJTdc.4957$>...
    > [POSTED TO rec.photo.digital - REPLY ON USENET PLEASE]
    >
    > In <> on 10 Apr 2004 07:17:11
    > -0700, (George Preddy) wrote:
    >
    > >John Navas <> wrote in message news:<ooNdc.4922$>...

    >
    > >> >Often times the size will stay the same or even go up on the second or
    > >> >third JPEGing, and the unique color count will skyrocket. This is of
    > >> >course a disaster from an optical perspective, since all the new
    > >> >unique colors are statistical noise.
    > >>
    > >> Nonsense.

    > >
    > >Oh, I forgot to mention that only for you lossy JPEG is lossless.

    >
    > No, just essentially indistinguishable from the original


    All JPEGs look as bad or worse than this "smooth gradient"...

    http://www.pbase.com/image/25651950/large.jpg

    Your laughably low standards make pros like me want to hurl.

    > You still haven't taken my bet, so that would seem to put the matter to rest
    > (for the rest of us at least -- you never seem to rest:).
    >
    > >> >JPEG should never, ever be used if you care about an image in the
    > >> >slightest, especially if you potentially might retouch/crop it.
    > >>
    > >> Rubbish.

    > >
    > >Your standards are in the dirt.

    >
    > My standards are based on hard evidence. Yours are hot air.


    The "hard evidence" is that a JPEG from a RAW image discards 95% of
    the unique color count, and precisely 4095/4096ths of the color
    palette. YOu don't want to believe the blatantly obvious becasue it
    JPEG is in fact lossy (believe me it is, see the

    Simple as this: if you shoot JPEG your images are worthless from a pro
    perspective, no matter what your skill level.
    George Preddy, Apr 11, 2004
    #9
  10. Xtx99

    Guest

    In message <>,
    (George Preddy) wrote:

    >Your standardds are in the dirt.


    Open your eyes, and notice that the color artifacts of the SD9 are far
    more pronounced than any light or medium JPEG compression.
    --

    <>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
    John P Sheehy <>
    ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
    , Apr 11, 2004
    #10
  11. Xtx99

    Guest

    In message <>,
    (George Preddy) wrote:

    >All JPEGs look as bad or worse than this "smooth gradient"...
    >
    >http://www.pbase.com/image/25651950/large.jpg
    >
    >Your laughably low standards make pros like me want to hurl.


    Pbase uses a quick-and-dirty downsizing algorithm, which is one reason
    why some people submit "originals" that are 800 pixels wide or less, so
    people will see these "originals" by default.
    --

    <>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
    John P Sheehy <>
    ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
    , Apr 11, 2004
    #11
  12. Xtx99

    John Navas Guest

    [POSTED TO rec.photo.digital - REPLY ON USENET PLEASE]

    In <> on 10 Apr 2004 19:24:39
    -0700, (George Preddy) wrote:

    >John Navas <> wrote in message news:<AJTdc.4957$>...


    >> No, just essentially indistinguishable from the original

    >
    >All JPEGs look as bad or worse than this "smooth gradient"...
    >
    >http://www.pbase.com/image/25651950/large.jpg


    That chestnut yet again? I've already shown that JPEG is capable of results
    essentially indistinguishable from the original on that kind of gradient.
    <http://groups.google.com/groups?selm=PrC9c.2326$>
    I note that you still haven't accepted my bet.

    >Your laughably low standards make pros like me want to hurl.


    You're not a pro, but feel free to hurl in any event.

    >> My standards are based on hard evidence. Yours are hot air.

    >
    >The "hard evidence" is that a JPEG from a RAW image discards 95% of
    >the unique color count, and precisely 4095/4096ths of the color
    >palette.


    Nonsense.

    >YOu don't want to believe the blatantly obvious becasue it
    >JPEG is in fact lossy (believe me it is, see the


    Of course it is.

    >Simple as this: if you shoot JPEG your images are worthless from a pro
    >perspective, no matter what your skill level.


    Nonsense.

    --
    Best regards,
    John Navas <http://navasgrp.home.att.net/>

    "Usenet is like a herd of performing elephants with diarrhea - massive,
    difficult to redirect, awe inspiring, entertaining, and a source of mind
    boggling amounts of excrement when you least expect it." --Gene Spafford
    John Navas, Apr 11, 2004
    #12
  13. Xtx99

    Guest

    wrote:

    > George Preddy <> wrote:
    >
    > > Often times the size will stay the same or even go up on the second or
    > > third JPEGing, and the unique color count will skyrocket. This is of
    > > course a disaster from an optical perspective, since all the new
    > > unique colors are statistical noise.

    >
    > > JPEG should never, ever be used if you care about an image in the
    > > slightest, especially if you potentially might retouch/crop it.

    >
    > I disagree [for good reasons].


    Note that The Preddy is negatively intelligent: further education
    just makes him more stupid. "Please don't feed the animals", and so
    on.

    > [...] I do not have the memory capacity to handle two or three
    > hundred raw images at a time while I am out shooting photos.


    The extra space taken by the raw images (at least in my 10D) has a
    subtle benefit: the lack of space forces you to edit the images
    closer to their time of collection, instead of deferring the task to
    "well, when I get home".

    On this subject of editing closer to the collection time, here is
    another enhancement request for "high end" digital cameras: a focus
    assessment computation upon user request. The camera divides the
    image into 128x128 blocks (or whatever), and measures the amount of
    power in the a high frequency band and compares it to the low. This
    information would be overlayed the image on the preview (postview?)
    screen to correlate with the underlying image. It should also be
    possible to shift the block boundaries to align with subject matter,
    maybe even changing their size and so forth. Extensions to the idea
    would be to automatically recognize motion blur, poor focus, and other
    clear candidates for erasure and simply ask the user if he wants to
    keep the image.
    , Apr 12, 2004
    #13
  14. John Navas <> wrote in message news:<qJ4ec.5044$>...

    > >Your laughably low standards make pros like me want to hurl.

    >
    > You're not a pro, but feel free to hurl in any event.


    Obviously I'm a pro and you are only a beginner, but even an solid
    amateur would hurl at your crazy suggestion of not shooting RAW in
    favor of lossy, third rate JPEGs.

    RAW is the only way to achieve consistent pro results, and all serious
    digital users know that. Canon users cringe at the that obvious fact,
    because Canon's RAW workflow is total garbage, and their cameras fail
    to give a full preview when shooting in RAW mode. That really stinks.

    > >> My standards are based on hard evidence. Yours are hot air.

    > >
    > >The "hard evidence" is that a JPEG from a RAW image discards 95% of
    > >the unique color count, and precisely 4095/4096ths of the color
    > >palette.

    >
    > Nonsense.


    How many colors in a 12-bit palette?
    How many colors in a 8-bit palette?

    That's before compression complete destroys the image. JPEGs are very
    low end, have a look this time...
    http://www.pbase.com/image/25651950/large

    If you shoot pro event and don't shoot RAW, you are ripping off your
    customers.
    George Preddy, Apr 13, 2004
    #14
  15. Xtx99

    John Navas Guest

    [POSTED TO rec.photo.digital - REPLY ON USENET PLEASE]

    In <> on 13 Apr 2004 04:42:44
    -0700, (George Preddy) wrote:

    >John Navas <> wrote in message news:<qJ4ec.5044$>...
    >
    >> >Your laughably low standards make pros like me want to hurl.

    >>
    >> You're not a pro, but feel free to hurl in any event.

    >
    >Obviously I'm a pro and you are only a beginner,


    Because you say so? I've sold work professionally. And you? ;-)

    >but even an solid
    >amateur would hurl at your crazy suggestion of not shooting RAW in
    >favor of lossy, third rate JPEGs.


    I made no such suggestion.

    >RAW is the only way to achieve consistent pro results, and all serious
    >digital users know that.


    JPEG is quite capable of professional results, as I've shown in prior
    responses.

    >Canon users cringe at the that obvious fact,
    >because Canon's RAW workflow is total garbage, and their cameras fail
    >to give a full preview when shooting in RAW mode. That really stinks.


    Rubbish.

    >> >> My standards are based on hard evidence. Yours are hot air.
    >> >
    >> >The "hard evidence" is that a JPEG from a RAW image discards 95% of
    >> >the unique color count, and precisely 4095/4096ths of the color
    >> >palette.

    >>
    >> Nonsense.

    >
    >How many colors in a 12-bit palette?
    >How many colors in a 8-bit palette?


    Irrelevant.

    >That's before compression complete destroys the image. JPEGs are very
    >low end, have a look this time...
    >http://www.pbase.com/image/25651950/large


    That chestnut yet again? I've already shown that JPEG is capable of results
    essentially indistinguishable from the original on that kind of gradient.
    <http://groups.google.com/groups?selm=PrC9c.2326$>
    I note that you still haven't accepted my bet.

    >If you shoot pro event and don't shoot RAW, you are ripping off your
    >customers.


    My customers don't get ripped off. Do you even have any customers? ;-)

    --
    Best regards,
    John Navas <http://navasgrp.home.att.net/>

    "Usenet is like a herd of performing elephants with diarrhea - massive,
    difficult to redirect, awe inspiring, entertaining, and a source of mind
    boggling amounts of excrement when you least expect it." --Gene Spafford
    John Navas, Apr 13, 2004
    #15
    1. Advertising

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