Digital BW, The Print

Thanks Paul, that was helpful. I also found & read Dirk Hobman's article 
which also clarified what you said. In the end I started with a standard 
  warm carbon curve, brought in the blue curve along the lines you 
suggested & then raised the red curve from the 165 mark ending at 229 
to compensate for the extra light ink.

There's alway the danger of losing separation between patches & the 
tweaking required made me appreciate the time & effort you have spent 
developing these curves.

Howard

Paul Roark wrote:
> I don't have Photoshop curves posted for the option of having UT-FS-Y in the
> yellow spot, but in general, I have the Blue curve (controlling the yellow
> ink spot -- FS-Y) carry the image entirely until about 229 on the horizontal
> axis, where I start the other inks (Red and Green curves).  
> 
> As an example, for Kirkland, a neutral curves set I use has the following
> points from 0% (255) to 25% (191):  (255, 254), (251, 187), (247, 168),
> (242, 147), (229, 99), (216, 88), (204, 83), and (192, 82).  
> 
> For glossy Kirkland, I taper it off to (127, 146), (25, 0).  For a matte
> paper the blue curve has to be full on at (0, 0) to help turn on the black
> ink.  So, for a matte paper it'd be either raised and then lowered again or
> go about level, perhaps at a bit higher point so that the other inks were
> not limited too much.
> 
> The Red and Green curves, as noted, start at 229, and are raised about 5 at
> 191 and about 15 at 127 relative to the starting curves that did not use
> FS-Y.  I don't have a good comparison here, because I used the Ilford curves
> for Kirkland, which were not right on to start with.  Print a 21-step with
> the current, starting curves and just eyeball the 50% and 25% patch
> densities to see how much the Red and Green curves need to be raised to
> offset the addition of the FS-Y.
> 
> Hope this helps.
> 
> Paul
> www.PaulRoark.com 
> 
> 
> 
>