[argyllcms] Re: output ICC gamut in RGB
- From: <robert@xxxxxxxxxxxxxxxxxx>
- To: <argyllcms@xxxxxxxxxxxxx>
- Date: Sun, 26 Oct 2014 11:53:26 -0000
It seems to me that whether or not the goal is worth achieving that
Lars-Daniel has asked a reasonable question: how can we see the numeric
values of the data that is sent to the printer driver?
Well, one way would be to convert the image to the print profile and measure
the value. I did this through a profile with 5 spot colors going from
0,160,0 to 0,250,0 (in AdobeRGB) and I was rather surprised to see that the
converted colors were all fully saturated in the green, except for the
0,160,0 which became 38,249,0; all of the colors also had significant
amounts of red in them and some blue - for example the 0,240,0 became
89,255,22. The same color (0,240,0) converted to the same paper but using a
profile made by a different profiler (Argyll instead of i1Profiler) becomes
111,255,30.
I don't really understand what is going on but if I did then I would
certainly learn something.
My initial interpretation is that the profiles are attempting to simulate
the saturation of a green by adding red and blue ... which is completely
crazy because red and blue certainly don't make green.
On second view I see that the CMYK values are all a combination of cyan and
yellow with no magenta ... so that will certainly give green. But of course
the CMYK values I see in Photoshop are based on the CMYK profile selected
... further muddying the water (or ink).
So I have to agree that getting the RGB values sent to the printer driver
seems a rather futile exercise ... except that it might shed some light on
what is actually going on ... and a careful choice of target might give some
idea of whether one profile was doing a better job than another.
For example, i1Profiler and Argyll give quite different values even though
the rendering intent is the same for both: looking at a soft-proof on screen
it's clear that Argyll is shifting the green towards yellow much more than
i1Profiler ... and this can be seen in the CMYK values where yellow is
significantly higher in Argyll than in i1Profiler (or if a different CMYK
profile is chosen, cyan is lower in Argyll than in i1Profiler while yellow
is held at 100%).
Robert
-----Original Message-----
From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx]
On Behalf Of Ben Goren
Sent: 26 October 2014 01:57
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: output ICC gamut in RGB
On Oct 25, 2014, at 6:26 PM, Lars-Daniel Weber <Lars-Daniel.Weber@xxxxxx>
wrote:
> Sure, but I want a numeric listing :)
Might I suggest?
This sure sounds like an intermediate step to some other goal, and I
strongly suspect that it's not the ideal path to whatever that goal may be.
If you fill in a bit more context, you may be pleasantly surprised....
b&
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