Re: untagged RGB data
Re: untagged RGB data
- Subject: Re: untagged RGB data
- From: Chris Murphy <email@hidden>
- Date: Fri, 19 Dec 2003 13:07:20 -0700
On Dec 19, 2003, at 12:38 PM, Andrew Rodney wrote:
The problem is there are a number of products that produced untagged
files
closer to Adobe RGB (DSLR's). So there are products producing untagged
RGB
that's not anything like sRGB. It would be nice to be able to pick
Adobe RGB
in such cases. But I agree that untagged files are the problem here.
My response :)
1. Why are they untagged?
2. What application is being used to initially read these files? And
why can't that application have an interface to allow for assigning an
appropriate profile to it?
3. Again why is the ONLY correct way to do this through assumption?
Example - Image Capture in OS X has an option to embed a specific
profile to all images it captures and saves out. (That it doesn't
actually do this, and instead embeds "Apple CMM DevLinkProfile",
regardless of what I select is a separate issue.)
We're talking about how these images behave in applications like Word,
Keynote, Excel, Preview, iPhoto, etc. Apps that don't have their own,
vendor developed color management system built-in. How many people use
DSLR's are sticking their untagged, uncorrected, un-Photoshop'd images
directly into any of these applications?
The slew of DSLR cameras that allow the user to shoot into TIFF or
JPEG and
pick "Adobe RGB" (quotes on purposes <g>) verses the two or three
different
flavors of "sRGB" you can choice from (which alone should tell you how
confused the camera manufacturers are about color).
What application is the first point of contact for these files?
Which brings me to another point (why we might need more than sRGB).
On the
Canon's (and I think others), you have THREE different sRGB options.
How
dumb is that? I'm under the impression that sRGB is sRGB (you can
certainly
see the guts of what sRGB is when viewing the custom space in Photoshop
where you can view the white point, gamma and chromaticity values). So
how
can the camera manufacturers allow users to pick not one but THREE
different
sRGB settings?
It is a perversion that I'm not inclined to encourage by having three
different sRGB settings in the ColorSync preferences window! They can
either embed them in their images, or too frigging bad.
Anyway, it's possible that some modification of the values
above could produce better color appearance since we all know the
cameras
are not producing sRGB (let alone 3 variants). Some users might want
to have
a way to assume a modified space FROM sRGB.
That should be up to the camera to do, or the image capture software.
Assumption should be discouraged when it comes to initial point of
contact with images from a digital camera. Having functionality to
assign, including batch assigning, including automatic batch assigning
are good options to have. I'm not saying we should not have those
options. I'm saying they shouldn't be a core operating system level
selection that affects EVERYTHING indiscriminately.
You are talking about a capture issue, and wanting to solve that
problem with a really blunt object through brute force - the OS. And
you are also talking about permanent assumption which does NOTHING in
the way of making those images tagged which is what they really need.
The real issue here is that the images you are using as an example need
to be tagged. Assumption is not a safe workflow for DSLR images.
Certainly not for the typical
users but nice to have. So I think a "back door" (maybe an advanced
preference that opens this back door), allows something other than
sRGB to
be assumed for the untagged files.
I'm still not convinced. I'm totally open minded still, but I haven't
heard a convincing argument. The "I want choice" people are only
expressing support for user selectable RGB Default because they haven't
been given any other options for how to get "choice" - NOT because it's
the right thing to do and subject millions of users to.
Bottom line is I think options are in order. However, I have no problem
assuming all untagged files are sRGB until I run into a situation
where they
clearly are not previewing correctly in which case, I need to get to
that
back door and make a new (better?) assumption.
System Preferences>RGB Default would affect *all* images on the system.
Not just the new ones that you're suddenly having a problem with. And
it doesn't cause that profile to be embedded. It's a single assumed
profile setting for anything untagged.
That's why I keep saying we need more options in the applications to
TAG our images. Not use RGB Default pop-up menu as a hammer. That's a
very crude hack and it does nothing to solve the underlying problem of
untagged images. It just brings users the power to have random
assumptions. Seems like a bad idea to me.
Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
---------------------------------------------------------
Co-author "Real World Color Management"
Published by PeachPit Press (ISBN 0-201-77340-6)
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