Re: Photoshop 6 Duotone Mode, Working Spaces & Profiles (was APS7)
Re: Photoshop 6 Duotone Mode, Working Spaces & Profiles (was APS7)
- Subject: Re: Photoshop 6 Duotone Mode, Working Spaces & Profiles (was APS7)
- From: "Stephen Marsh" <email@hidden>
- Date: Sun, 17 Mar 2002 23:56:44 +1100
Neil writes:
>
>> I reopened the CD recently and looked at the original duotones with a
view to a little reworking. Imagine my surprise when the colour looked
absolutely awful, after many hours of pleasure I discovered that the
CMYK setup chosen has a large influence on a duotone image. Not just
tonal either. Photoshop 6 could not provide me with a setting which
worked on the files.
In the end I had to switch to 5 with the default Colorsync CMYK [I
think] selected to get the appearance back to that intended.
Now, if the CMYK space has such an immense effect on a saved Duotone
image would it not be useful to embed that profile in the saved file??
Or to provide some kind of record to assist reopening? Am I missing
something here? <<<
Neil, I am having problems following your post.
This is my basic understanding of the situation in Photoshop 6 or earlier.
The colour definition of a Duotone mode file is often independent of the
working spaces chosen in colour settings, it resides in it's own little
world based around the preset colour libraries from Pantone and others. The
use of the custom colour picker using LAB, or RGB/HSB/CMYK values - are tied
to the colour settings. So it depends on how you originally define the
colour build, as to the way things behave. Photoshop 6 uses a dotgain
profile for image display, but I am pretty sure that this does not have any
role in conversions inside Photoshop, or that the profile actually does
anything outside Photoshop when the file is in Duotone mode EPS format.
So depending on how you define colour when you create the Duotone file, it
will either be a closed loop library file or ICC compliant and tied to your
colour settings. Once you have defined the ink and left the Duotone dialog
box, changing the CMYK set-up will have no effect on the current file in
Duotone mode, even if the colours were defined via custom CMYK values which
are tied to a certain work space. The colours are now locked in.
For users who simply accept default library builds of Pantone and other
named inks using Duotone mode, the CMYK work space has no meaning. For users
who define their own custom Duotone mode inks, the colour settings for RGB
and CMYK do play a critical role. But once again, when the Duotone dialog is
closed, the LAB values of whatever colour mix are locked in, and changing
working space should not matter one bit to the file as it stands.
So I fail to see how the Duotone mode files can change colour when the CMYK
WS changes - the definition is locked into the Duotone format options and
the WS only kicks in when you mix the colours, then they are locked.
Now if you originally built the Duotone mode colours using a different CMYK
WS and dialled in the colour as custom CMYK values, then you will get the
LAB values for this CMYK mix, as referenced from the colour settings CMYK
WS. If you change the CMYK WS, then go back to Duotone mode and re-enter the
same CMYK values - you will obviously get a different LAB build than before
(different colour). The idea would be to enter the same LAB values as
previously, to force Photoshop to recalculate the new CMYK build to the new
WS, giving you the same apparent colour.
Your situation is different to users who use the default non ICC ink set
build then incorporate this duotone into layout and illustration software
for separation - since your use of Duotone is only for artistic purposes
before a conversion to RGB, so things should be easier to troubleshoot.
That's enough for now, I am sure your reply will make the entire situation
become crystal clear to me. I hope I have not confused things, this is a
tricky subject.
Regards,
Stephen Marsh.
_______________________________________________
colorsync-users mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/colorsync-users
Do not post admin requests to the list. They will be ignored.