Digital BW, The Print

Helen,

I cannot comment on IJC/OPM -never used it. Over the Epson driver, 
the advantage of my QTR method is that only the chosen channel will 
fire. We don't know how the Epson driver works, so there is no 
telling which color values will fire only one channel.

The numbers I reported to you were picked off from the 
QTR "calibration" image. Roy Harrington (or someone else) has 
generated specific color numbers to fire each single ink channel at 
5% increments so as to to find ink limits.

It would be very, very easy for you to try. If you are on a PC I can 
walk you through it. E mail me off-list if interested.  BTW, I know 
of this trick because I use it if I want to purge ink from just one 
channel - I am always trying out new inks ;-(.

Shilesh

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "helen_bach2003" 
<helenbach@h...> wrote:
>
> Thanks Shilesh, if I decide to try QTR I'll give that a go. What
> advantages does it have over just using the Epson driver for this
> particular purpose? What advantages would it have over IJC/OPM?
> 
> I fixed the problem in OPM by making a profile that used more active
> inks, but with all of their ink curves zeroed at zero pixel value 
(my
> coating image is all black). But OPM is still a lot slower than the
> Epson driver, and speed appears to help in the avoidance of faint
> wheel marks. 
> 
> As an aside, why does 251, 0, 255 result in QTR delivering 100% LM
> rather than 100% M?
> 
> Thanks,
> Helen
> 
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Shilesh Jani"
> <shileshjani@b...> wrote:
> >
> > Helen,
> > 
> > If you want to overspray a print you gave already made using a 
single 
> > ink channel, the best bet is to use QTR.
> > 
> > Here is how you do it:
> > 
> > (1) You have to create an RGB untagged TIFF file of the size you 
want 
> > overprinted.
> > 
> > (2) Fill the entire image with a solid color. The choice of color 
to 
> > fill depends on which channel you have loaded your Tipkote. Below 
I 
> > list the RGB color values for the LM channel for Topkote.
> > 
> > (3) Save the image as a TIFF, untagged.
> > 
> > (4) Open QTR
> > 
> > (5) Select "calibration" in the options drop-down menu
> > 
> > (6) It will open a default calibration image, so you go 
> > to "image", "select image" to open your file.
> > 
> > (7) Print, and viola!
> > 
> > You have the option of selecting ink (Topkote coverage in 5% 
> > increments.
> > 
> > Good luck and let us know how it works out.
> > 
> > Shilesh
> > 
> > Below are the RGB numbers for LM:
> > 
> > The numbers R=251 and B=255 remains the same for all %. The 
number G 
> > is listed
> > 
> > 5% = 242
> > 10% = 230
> > 15% = 217
> > 20% = 204
> > 25% = 191
> > 30% = 179
> > 35% = 166
> > 40% = 153
> > 45% = 140
> > 50% = 128
> > 55% = 115
> > 60% = 102
> > 65% = 89
> > 70% = 77
> > 75% = 64
> > 80% = 51
> > 85% = 38
> > 90% = 26
> > 95% = 13
> > 100% = 0
>