Re: 100% GCR with UCA?
Re: 100% GCR with UCA?
- Subject: Re: 100% GCR with UCA?
- From: email@hidden
- Date: Tue, 21 Oct 2003 08:35:59 EDT
In a message dated 10/21/03 6:28:11 AM, email@hidden writes:
>
Perhaps you can clarify my concerns over the late black start. Will this
>
not affect the GCR settings? I need all neutral images to be replaced with pure
>
black, as far as is possible. Will not the late black start undo what the
>
GCR settting has done up until the point where the black chanel start is
>
defined by the custom curve? Perhaps the black should start at zero?
>
If your goal is for all gray component to be rendered to the black channel,
then the setting you need is "maximum" for black generation; which would indeed
be a zero toe, and a 45 degree ramp from there. This will seperate all
balanced gray components to the black channel. It sounds like you are actually
trying to do the opposite of the usual. Typically black is excluded at the light
end, and used exclusively at the dark end. You appear to want black only at the
light end, with color mixed back in at the dark end, ending with a rich black.
If you start with the with the maximum BG setting, and add in about 20 or 30
percent UCA the lower half of your ramp will remain all black, before the
color starts being added back in. If that starts adding color too soon, set UCA
back to zero, and try nailing the first three quarters of the BG ramp with
control points to keep it steady, then adding a couple control points in the dark
end to judiciously add a dip in the ramp down from the upper right corner.
This will leave all neutral components in the black channel up until the point
of your dip in the ramp, where CMY will start getting added back in. Remember
that total ink does not guarantee that amount, it simply provides assurances
that you won't get more than that amount, in other words its a cutoff.
C. David Tobie
Product Technology Manager
ColorVision Inc.
email@hidden
www.colorvision.com
_______________________________________________
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.