Converting from AdobeRGB to SRGB

Discussion in 'Digital Photography' started by Alfred Molon, May 12, 2006.

  1. Alfred Molon

    Alfred Molon Guest

    Suppose you convert a RAW image to JPEG using the AdobeRGB colour space
    and save it. If you then convert it to SRGB for web display, you might
    end up with clipped highlights or burnt shadows, because AdobeRGB has
    more dynamic range than SRGB. Is this correct?
     
    Alfred Molon, May 12, 2006
    #1
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  2. Alfred Molon

    Jim Guest

    No. The difference is that the gamut of sRGB is smaller than that of Adobe
    RGB. This means that some colors in AdobeRGB can only be approximated in
    sRGB. You might be hard pressed to see the difference.
    Jim
     
    Jim, May 12, 2006
    #2
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  3. Alfred Molon

    Alfred Molon Guest

    But if a colour is out of gamut, it should be clipped, shouldn't it?
    When you convert a RAW image with lots of dynamic range, it can happen
    that the blown highlights indicator pops out if you choose SRGB and not
    if you choose Adobe RGB.
     
    Alfred Molon, May 12, 2006
    #3
  4. Alfred Molon

    Jim Guest

    It is not necessarily a good idea to merely clip the color at the edge of
    the gamut.
    In any case, clipping is just one method of aproximating out of gamut
    colors.
    Jim
     
    Jim, May 13, 2006
    #4
  5. Alfred Molon

    Stacey Guest

    I'm not going to try to explain why converting from aRGB to sRGB doesn't act
    this way, but it ussually doesn't. The only time I've seen the difference
    on a monitor is when the color in aRGB is WAY out there, like with a really
    saturated blue or yellow. I had to work to get this image to look OK in
    sRGB because of how vivid this yellow is.

    http://img.villagephotos.com/p/2005-1/937049/springweb2.jpg

    When I run into this, I use soft proofing with gamut warning enabled and
    then desaturate the specific color till it "gets in line"..
     
    Stacey, May 13, 2006
    #5
  6. Alfred Molon

    Alfred Molon Guest

    That's what I meant. When the image contains a lot of dynamic range,
    with highlights close to 255 or even brighter, in Adobe RGB the image
    might not have clipped highlights, when in SRGB they are clipped.
     
    Alfred Molon, May 13, 2006
    #6
  7. Alfred Molon

    W (winhag) Guest

    Yes, I agree this can happen. I have seen a more obvious 'version' of
    this when using ProPhoto (larger gamut than AdobeRGB1998). I had a RAW
    file which had bright orange/red elements (fall foiliage in the sun).
    It did not clip in ProPhoto, but clipped in aRGB and sRGB when using
    Adobe Capture Raw.
     
    W (winhag), May 13, 2006
    #7
  8. Alfred Molon

    Stacey Guest

    I'd develop the image in aRGB and then figure out how to desaturate the
    specific problem color to get it back inside sRGB withough clipping. I've
    also found sometime converting using "saturated" intent will work when this
    is a problem to avoid clipping saturated colors to white when only one
    specific color is a problem.
     
    Stacey, May 14, 2006
    #8
  9.  
    Steffen Kluge, May 16, 2006
    #9
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