CMM "interfering" with PS color picker?
CMM "interfering" with PS color picker?
- Subject: CMM "interfering" with PS color picker?
- From: Roger Breton <email@hidden>
- Date: Thu, 01 Feb 2001 09:01:11 -0500
Chris and others,
It is interesting to note that 255/255/255 in RGB always maps out to 0/0/0/0
in CMYK for ColorSynergy. Whenever I can, to match single images in
Photoshop, I never use the P2P or Convert to Profile conversion in favor of
Candela's Photoshop Plug-In (which works equally well with 5.x or 6) as it
lets me draw upon the Candela Color Engine from within Photoshop.
The same argument can be made, I guess, for calling the Kodak Plug-in for
ColorFlow or the AGFA Plug-In for ColorTune.
Roger Breton
QIGC
>
It is beyond my comprehension why in the year 2001 this is still a
>
problem. I understand that different CMM's do different kinds of white
>
point adaptation and that's the likely cause, but for crying out loud by
>
*NOW* we should have figured out that 255,255,255 should *always* render
>
to 0,0,0,0. I mean even the ICC spec says there is no white point
>
simulation using perceptual, relative colorimetric, saturation intents.
>
ONLY absolute colorimetric should map source white to destination.
>
>
The only thing I can think of is there is a combination "bug" (whatever
>
you want to call it, it's definitely NOT a feature) between CMM's and
>
various ICC profiles which makes this so hit or miss. And that Adobe's
>
engine/CMM has some kind of means of more intelligently mapping
>
255,255,255 RGB to 0,0,0,0 CMYK.
>
>
I don't know if the CMM has the ability to "override" a request by the
>
profile to map white to something other than white, but if it can, I
>
don't understand why CMM's have yet to take advantage of this and do the
>
override on a consistent basis.
>
>
At least in Terry's case, going from ProfileMaker 3.1.3 to 3.1.4 solved
>
the problem, but only in regards to the Adobe CMM. So whose fault is it?
>
The fact that it's now fixed with the Adobe CMM points to a problem with
>
ProfileMaker 3.1.3. But both 3.1.3 and 3.1.4 make profiles that cause
>
something other than 0,0,0,0 CMYK to print with *OTHER* CMMs. That points
>
to a problem with the CMMs.
>
>
This is completely absurd. I really would like someone to explain this to
>
me.
>
>
As noted on another list, this issue with ICC profiles and CMMs mapping
>
RGB 255,255,255 to something other than 0,0,0,0 CMYK led an advertiser to
>
refuse to pay for a newspaper ad. Cost was in the five figure range. So
>
this is potentially a significant problem. (Also it seems to happen only
>
with 3rd party profiles. Not with ink settings files, or Photoshop
>
created ICC profiles.)
>
>
>
Chris Murphy