Re: dangerous automatic ICC profile conversion É ;-(
Re: dangerous automatic ICC profile conversion É ;-(
- Subject: Re: dangerous automatic ICC profile conversion É ;-(
- From: Doug Broussard <email@hidden>
- Date: Tue, 07 May 2002 23:41:12 -0700
on 5/7/02 10:07 PM, email@hidden at
email@hidden exposited thusly:
>
Somehow the OS has changedI
>
>
In Mac OS X 10.1.3, if you aquired pictures from your digital camera, they had
>
no ColorSync
>
profile ("UNTAGGED RGB"). Now, in 10.1.4, all pictures get an sRGB profile, no
>
matter what your
>
prefs are.
Hrrrm. I'm not sure this is true. I'm not doubting that the behavior has
changed, but I think you're assigning the behavior to the wrong component in
this situation.
Perhaps ColorSync's behavior has changed in 10.1.4 with regards to camera
tagged profile handling, but I believe the profile you're seeing is assigned
in camera when the file is written.
Does your camera incorporate print image matching (PIM)? It's an Epson
technology, but several major digital camera manufacturers have incorporated
it into the newest models. My CoolPix 5000 manual makes no mention anywhere
about profiles, tags, or sRGB, but the PIM sticker is right there on the
Nikon retail box.
If your camera, imaging software and printer driver support PIM, supposedly
you'll get 'consistent' color from device to device. In a nice cramped color
space of course...
My hypothesis is this: Cameras with PIM assign an sRGB profile to the JPEG
file when it is written. This is what you're seeing, not some mysterious Mac
OS generated profile.
I tested my hypothesis by viewing file attributes with the Photoshop 7.0
file browser, which shows EXIF information written by the camera, including
the PIM profile information. Raw files (TIFFs) do not carry EXIF
information. JPEGs always do.
Sure enough, there's the info: EXIF version 0210, EXIF Color Space sRGB -
the same version and color space Photoshop reports my files are tagged with.
There's one cause of the behavior you describe.
Another cause could be the ColorSync Utility.app.
I investigated this by checking the Devices pane of the ColorSync
Utility.app, and sure enough, the default profile for my Nikon Digital
Camera E5000 is sRGB. Oddly, this profile is only assigned to JPEG files,
not TIFFs - there is no evident way to change this preference.
Here's how to change the camera profile:
1. Open ColorSync Utility.app, located in ~/Applications/Utilities
2. Click the Devices icon.
3. Click the Cameras item in the list, and look for your camera.
4. Click the Change button and assign a custom profile to your camera.
These changes must be made for and by each user of the machine.
Unfortunately, I cannot change the behavior you describe by assigning a new
profile to the camera. No matter what I do, files from this camera are
always tagged with the PIM sRGB profile. This might change if you copy files
form the camera directly instead of using iPhoto.
My problem is this: There is NO documentation about any of this anywhere on
Nikon's site, and Apple's tech info library is thin on details as well.
There's also no way to turn off PIM on my CoolPix 5000. Perhaps on the
higher end SLRs, but not on my camera!
Hope this doesn't muddy the waters any more. I'd appreciate any other
insights into this behavior. (I've also got an application in at Apple for a
tech writing job; hopefully this post makes sense and someone influential
sees it!)
-D
--
Doug Broussard
Instructor, PhotoClassroom
http://www.photoclassroom.com
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