Re: Photoshop 6 Duotone Mode, Working Spaces & Profiles
Re: Photoshop 6 Duotone Mode, Working Spaces & Profiles
- Subject: Re: Photoshop 6 Duotone Mode, Working Spaces & Profiles
- From: "Stephen Marsh" <email@hidden>
- Date: Wed, 20 Mar 2002 14:29:39 +1100
>
> Photoshop 5.x got the duotone ink dot gain from the dot gain of the
black channel of the current CMYK space.
Photoshop 6 and later get the duotone ink dot gain from the spot dot
gain setting in color settings.
Thomas Knoll. <<
Thomas, firstly - thank you for your interest and response. How about
answers to these questions, now that the full depth of the issue has been
noted:
* Why do both CMYK and Spot WS set-ups in ver6 impact on the Duotone file
created with custom colour picker, why not one or the other - why
'calibrate' twice on the same image?
* Why is it that default colour book library colours are NOT linked to the
CMYK WS and are only affected by Spot WS settings? I guess this is the part
of your answer about how things changed in ver6 from 5.
* How does one stop the Duotone colour picker settings from changing, if you
use custom picker builds - and the file is opened with different CMYK
settings? As you say, CMYK should not matter in ver6 - BUT IT DOES.
* How do you 'tag' the CMYK and or Spot WS to the Duotone file, since this
has a critical impact on opening the Duotone file and converting to other
modes? EPS, PDF and PSD Duotone don't seem to support ICC methods of knowing
about the colour characteristics of the file.
* Why is it that Photoshop is both the inset and dotgain, you only mention
dot gain.
* And while I have your ear - or is that eyes...What colour is used in the
EPS file to send composite values to the RIP for non separated composite
proofing? LAB for the Pantone colour in question, or the CMYK values that
are nominated for the colour via library or colour picker, instead of LAB?
From my testing, common graphics apps read the imported EPS as a CMYK build
colour, and not LAB or RGB? I think I understand separations, just not what
is happening at composite print.
I have to presume this is a huge crawling insect - since the problems were
not commented on, only what should be. It seems that Photoshop is using both
settings at once, or only one - depending on how the colours are defined.
In ten years of use, I have never seen this documented - and due to workflow
practices I have not encountered this issue until Neil pointed out his
problems. I can't find any explicit mention of these issues in Adobe
documentation.
I have a feeling PostScript and the newer ICC way of doing things are not
working hand in hand - and Photoshop is getting very confused about how to
handle Duotone mode in an ICC world. On second thought, that is not really
true either, since Photoshop 4 without any ColorSync plugs has this CMYK
set-up and custom colour picker issue too.
Although confusing, my previous email attempted to concisely and technically
document the issues involved and how they can be reproduced by any user
using any version of Photoshop.
If you would prefer to discuss this off a public list - then I will post on
the pre-release or you can email me direct.
Sincerely and respectfully,
Stephen Marsh.
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