iPhoto 5 and Keynote 2 observations, was: ColorSync inconsistency in iPhoto
iPhoto 5 and Keynote 2 observations, was: ColorSync inconsistency in iPhoto
- Subject: iPhoto 5 and Keynote 2 observations, was: ColorSync inconsistency in iPhoto
- From: Chris Murphy <email@hidden>
- Date: Mon, 14 Feb 2005 17:09:06 -0700
On Feb 11, 2005, at 1:43 AM, Pete Carter wrote:
Ok Ive now tried this with a ColorChecker 24 . Ive two copies in
iPhoto,
both tagged with sRGB. I crop one in iPhoto and click done.
Ive set to open images in Photoshop. The cropped one now has embedded
Generic RGB and the other still sRGB. The Generic RGB image is
Washed out in comparison with the other.
This seems to happen when using any editing tool that writes back to
the
file.
If someone tells me that this is good practise
I will eat this ColorChecker.
I've done the following initial tests with iPhoto 5.01
1. Add TIFFs and JPEGs, tagged and untagged, to iPhoto.
a. Duplicates are made and stored in the iPhoto Library
b. The duplicates contain the profiles in the originals. If the
original does not have a profile, the duplicate also has no profile. No
conversions have occurred.
2. On-screen preview of these images appears to not use the currently
selected Display profile. No matter what profile I choose in
Displays>Color>Display Profile, the on-screen preview remains the same.
Digital Color Meter reports RGB values of variously tagged test images
as having the same RGB values if I convert the test images to Generic
RGB. At this point, it appears there is no display compensation in
iPhoto. [If Pete Carter is calibrating/profiling his display with a
gamma greater than 1.8, such as 2.2, or native display gamma, this
accounts for his experience where the cropped & converted (sRGB>Generic
RGB) copy looks washed out compared to the sRGB original.]
3. Using any of the edit functions (e.g. crop or enhance) causes the
copy held in the iPhoto Library to be modified. The RGB values in the
file are consistent with a conversion to Generic RGB. The resulting
file has Generic RGB embedded. However, it is displayed using raw RGB
values in the now converted file, there is no display compensation
(Generic RGB>Display RGB).
4. Upon modifying an image, a copy is stored in an Originals folder and
remains unmodified while a duplicate is modified. Revert to Original is
available for these images, but so far it's the only way I've found to
determine if a file has been modified from the original. Side by side
comparison of original and edited versions isn't possible. You either
have to accept the edited version, or accept the original. If you
choose to revert to the original, you lose the ability to go back to
the edited version (a warning pops up saying this when choosing to
revert to the original.)
5. Filesystem creation dates of both duplicates (for edited versions of
images), and original, are set to today's date. If your images don't
contain EXIF data, you lose the original creation date. This represents
another layer of data loss.
I've done a test with Digital Color Meter and Keynote 2 where I get
identical (+- one level) values sent to the display as when I take the
original images and convert them to Generic RGB. Regardless of the
Display Profile I have selected, there is no change in the on-screen
appearance of images placed into Keynote 2, including after relaunching
the app. It appears Keynote 2 also remains incapable of display
compensation.
Apple, display compensation is a basic and necessary color management
function. It was necessary in version 1.0 of both of these
applications, let alone in products that have shipped in the last
month. What's the deal?!
Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
-------------------------------------------------------------
Co-author "Real World Color Management, 2nd Edition"
Published by PeachPit Press (ISBN 0-321-26722-2)
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