Hi Dan,
The idea of a platinum look is warm highlights and cool shadows.
So you could do a LM, C, K profile, but as you see the tones are very
strong so it looks pretty weird. You can just Tone Blend a very small
amount of this curve with a neutral curve to get something pleasing.
But with the photo-platinum curve supplied the idea is to get a lot
closer
to neutral with the one curve and I think it would be easier to subtly
achieve the hues you want. As you see there are 2 curve copies in
the profile so shadows are done with C and M, highlights with LC and LM.
The "basic" ink limit for dark grays is 65 so instead of using just C
or M
the idea is to mix these two to get a desired shadow tone. The ink
limits
are set so C+M=65 and you just adjust to taste. Similarly LC+LM=65
for the highlights.
The COPY CURVE feature is a convenient way to get a fixed mix of
two inks throughout. It's like custom mixing a new color of ink.
Roy
On Sunday, June 11, 2006, at 12:09 PM, Dan wrote:
> howdy-
>
> firstly, i just started using QTR and am extremely impressed. truly
> awesome.
>
> Mac OS 10.4, MediaStreet GQ inks, & R200; do i create create a
> platinum curve just by using the light magenta, cyan, & black? is it
> really that easy? i've had great luck making my own neutral, warm, &
> cool curves but my platinum just looks funky.
>
> i ask because i'm not able to figure what's going on in the supplied
> platinum curve descriptor file ("Photo-platinum" in the "R200-R300-GQ"
> folder). C & LC curves are being copied to M & LM respectively. but
> where did the inklimits being used come from? is this still based on
> density or L*, or are these numbers kind of arbitrary?
>
> thanks,
> daniel
>
>
-
Roy Harrington
roy@...
Black & White Photo Gallery
http://www.harrington.com