Re: Rendering Intent for 3D plot in ColorSync Utility
Re: Rendering Intent for 3D plot in ColorSync Utility
- Subject: Re: Rendering Intent for 3D plot in ColorSync Utility
- From: Marco Ugolini <email@hidden>
- Date: Mon, 22 Mar 2010 18:30:33 -0700
- Thread-topic: Rendering Intent for 3D plot in ColorSync Utility
In a message dated 3/22/10 5:58 PM, david wollmann wrote:
> I thought this was discussed once before but I am unable to locate the
> specific thread in the archives. I am wondering what rendering intent
> is used for the 3D plot of color profiles in ColorSync Utility, and
> also ColorThink Pro?
ColorSync uses either a Relative Colorimetric intent with BPC or (more
likely) Perceptual. Fact is that it scales both the white and black point of
any profile respectively to absolute white and black. Obviously, that ends
up distorting the representation of actual 3D device gamuts quite
substantially.
What's worse, the user is not given a choice of rendering intent.
In ColorThink Pro, the user can choose which intent to use among any of the
four standard ones. There is also a "device gamut" button available, which,
as far as I can tell, produces the same 3D gamut projection as the one
achieved by selecting "Absolute Colorimetric".
> When I do a Hold for Comparison in ColorSync Utility v4.5 and then
> also compare the same two profiles in ColorThink Pro I get different
> views.
Sure. ColorSync's 3D projections are distorted (most often times massively)
by the scaling of the white and black points, and for that reason they are
utterly unreliable, as far as device gamut is concerned.
Of the two, ColorThink Pro is the application that gives you an accurate
projection.
> For example if I look at US Web Coated SWOP v2 and sRGB in ColorSync
> Utility one can see that there are many CMYK colors that extend beyond
> the sRGB boundary.
That's the kind of distortion caused by scaling the white and black point,
resulting in a projection that makes the profile look way out of proportion
to its actual size.
I truly fail to understand the practical usefulness of ColorSync's 3D gamut
projections as they are produced at the current time. Unless one day the
utility finally should offer a choice of intent, it's next to useless as a
device gamut projection tool for professionals, in my opinion.
Marco Ugolini
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