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Color Profile in iPhoto

2430 Views 14 Replies Latest reply: Feb 24, 2012 2:16 PM by Keith Barkley RSS
BPWMorro Level 1 Level 1 (70 points)
Currently Being Moderated
Feb 21, 2012 8:32 AM

Hello,

 

A friend, with iPhoto 9.1, imports images from a Panasonic camera and when he exports to burn to a CD they have a Camera RGB Color Profile -- which then displays lousy on a projector in a club competition.

 

When I import images from my Panasonic into iPhoto 9.2.1 and export they have an sRGB profile -- which displays nearly perfectly.

 

I cannot figure out how to help my friend assign an sRGB profile to his images. Any suggestions?

 

(PS -- I also have Aperture and Adobe CS, but my sRGB profile appears on my images without every opening Aperture or CS.)

 

Thanks,

Mac OS X (10.7.3)
  • LarryHN Level 9 Level 9 (54,915 points)
    Currently Being Moderated
    Feb 21, 2012 8:36 AM (in response to BPWMorro)

    Camera RGB and sRGB should be very close to each other

     

    As to assigining sRGB you can do it in Preview

     

    LN

  • Old Toad Level 10 Level 10 (113,315 points)
    Currently Being Moderated
    Feb 21, 2012 3:33 PM (in response to BPWMorro)

    Use the Colorsync Utility to compare the sRGB profile to the Camera RGB profile. With my camera the two profiles are very close together.

     

    sRGB IEC61966=2.1

    ColorSync Utility002.jpg

    Camera RGB Profile

    ColorSync Utility001.jpg

     

    See if your two profiles are close or not.  I have a couple of Automator workflows and an Applescript that can change the color profile to the sRGB profile.  You can get them from Old Toad's Cellar. You will have to apply the workflow to the photos outside of iPhoto and reimport them.

     

    OT

  • LarryHN Level 9 Level 9 (54,915 points)
    Currently Being Moderated
    Feb 23, 2012 6:44 PM (in response to BPWMorro)

    And did you try Old Toad's Applescript to change the color profile to sRGB?

     

    Did it help?

     

    LN

  • Keith Barkley Level 5 Level 5 (5,140 points)
    Currently Being Moderated
    Feb 23, 2012 7:17 PM (in response to BPWMorro)

    It really sounds like the profile used is much closer to AdobeRGB than CameraRGB.  It could be that the Panasonic just attaches a profile tag  instead of the profile and that the Panasonic Profile is actually far away from sRGB.

  • Keith Barkley Level 5 Level 5 (5,140 points)
    Currently Being Moderated
    Feb 23, 2012 7:27 PM (in response to BPWMorro)

    I don't know if this is true, but I saw in a post on dpreview that Camera RGB expects a Gamma of 1.8. If the projector is at 2.2, that could throw things off.

     

    ETA:

    Terrence as usual has the answer:

    https://discussions.apple.com/thread/1458772?start=0&tstart=0

     

    Since mac's use 2.2 gamma these days, there doesn't seem to be much point.

  • Terence Devlin Level 10 Level 10 (121,755 points)
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    Feb 23, 2012 11:03 PM (in response to BPWMorro)
  • Keith Barkley Level 5 Level 5 (5,140 points)
  • Terence Devlin Level 10 Level 10 (121,755 points)
    Currently Being Moderated
    Feb 24, 2012 1:04 PM (in response to BPWMorro)

    On the first wall you use two quarts of red.

              On the second wall you use only 1 pint of the identical same red.

              Won't the second wall be less ... intense....than the first?

     

    No it won't. The red is the red. There's no difference in the intensity. What might differ is the coverage - there's a greater risk of the old colour showing through, but that don't change the intensity of the red.

     

    If we translate this to images, consider a projector displaying a full size 8MB image, one that has not been image resized ("resampled") and also displaying the same image that has been resized (reduced) to one-quarter the size (from 8MB to only 2MB) -- wouldn't we expect the reduced image to display with less intensity, the same as the painted wall?

     

    We might expect it but it wouldn't necessarily be true. The compression involved in jpegs is very complex and it is quite possible that the two images will appear the same. For instance, if you follow your logic,  wouldn’t the blacks in the shot become grey?

     

    And, if my recollection of schoolboy physics is correct (and remember in my schooldays chalk was considered a new invention) colour produced by light works very differently than colour produced by pigment - one of the reasons it's so difficult to get a print that matches what you see on the screen. This might help explain the difference between additive and subtractive colour

     

    http://en.wikipedia.org/wiki/Additive_color

     

     

    Regards

     

     

    TD

  • Keith Barkley Level 5 Level 5 (5,140 points)
    Currently Being Moderated
    Feb 24, 2012 2:16 PM (in response to BPWMorro)

    wouldn't we expect the reduced image to display with less intensity, the same as the painted wall?

     

    Each pixel in the projector is independent*. If a particular pixel in the image is displyed red, it will be displayed red. It does not matter if it is surrounded by more red or blue - it might appear a different color because of the surrounding pixels, but that is your eye's fault, not the projector.

     

    When you resample, it works the same way. The resulting image has no memory of the previous image. If you down-sample a perfectly sharp checkerboard pattern the inside of the pattern will maintain the same color, though it will be at a lower resolution. The edges might have pixels that are in-between the two colors, but again that is not really what we are talking about here.

     

    *Of course in a poor projector, some pixel's may bleed into others, but I don't think that is what we are talking about here.

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