QTR-Quadtone RIP

Hello,

I am the proud owner of a mostly working Epson 4900. I would like to repurpose the orange and green channels to use them with pure black dye ink, for the creation of screen printing films, while leaving the other channels untouched. Therefore, I need to create a profile with only these two channels. Ideally, they both would print a 50% density, so in the end, I have a decent opaque film for exposure. I don't need any half tones or shades, just pure black and transparent parts.

So far in theory :-)

Now I'm stuck with the creation of such a profile. I tried to read each and every tutorial on QTR that I found, but I'm not finding what I'm looking for.

Some of the files I found within QTR have informations about the used colors and the used printers while some other have just long columns of numbers. Which are the right ones and how do I start out with this?

Is it even possible to do?

I know I can just go the route via the calibration mode and use the colors from the purge-images as a background color. I tested it and it works. However, I would prefer a profile so I could use both orange and green instead of just one, just to keep the ink flowing and not risking more dead channels.

Thanks in advance for any kind of help!

Kind regards,

Pugsley

Hello,


Sorry too if this goes further off topic.

Simone, I was reading the Gutenprint 5.2 user's manual when your post showed up!
I'm very interested in the pre-dithered output you have experienced: one pixel, one/zero droplet.
Could you please explain from which application(s) you printed the pre-dithered files and what are the possible file formats.
Could Print-Tool play a role here?

Roy, if Gutenprint is underlying QTR, could a future version of QTR handle the pre-dither option and assign a pre-dithered output to one (or two...) specified channels?
I'm also intrigued by Gutenprint's EvenTone dither option, though it is described as "somewhat prone to artifacts"...

Pugsley, have you considered screen printing dedicated dye inks (UV45, Blackmax...)?

Best,


Stefan

Pugsley,


I have tried the UV45 ink very briefly to make inkjet negatives with low ink limits.
It is of course very efficient in blocking UV, and it should help you to get greater densities.

I'm not very qualified to help you about making a profile for your specific set up, and hope you'll get some better help. Did you try to search conversations in the forum about the x900 printers and orange and green channels?
I'm not familiar with those and the profiles included in QTR are designed for ultra chrome inks without orange and green.
As you only want to use black inks in those two channels, you probably don't need to care about gray or toner partitioning.
Maybe something like this could work as a start; hope someones corrects me if I'm wrong...
And you probably need to be on a Mac.

N_OF_INKS=10
DEFAULT_INK_LIMIT=

LIMIT_K=
BOOST_K=
LIMIT_C=
LIMIT_M=
LIMIT_Y=
LIMIT_LC=
LIMIT_LM=
LIMIT_LK=
LIMIT_LLK=
LIMIT_O=50
LIMIT_G=50

N_OF_UNUSED=8
UNUSED_INK_1=K
UNUSED_INK_2=C
UNUSED_INK_3=M
UNUSED_INK_4=Y
UNUSED_INK_5=LC
UNUSED_INK_6=LM
UNUSED_INK_7=LK
UNUSED_INK_8=LLK

CURVE_K=
CURVE_LK=
CURVE_LLK=
CURVE_C=
CURVE_M=
CURVE_Y=
CURVE_LC=
CURVE_LM=
CURVE_O="0;0 100;100"
CURVE_G="0;0 100;100"

I'm curious about the kind of files you wish to print thru QTR? Grayscale? Pre-dithered files?
Do you only have white or black pixels in them or do you count on QTR to screen your films? 
Is your final application screen-printing or do you plan to use screen-printing films for an other process?

Also, I'm a bit confused, maybe because english is not my native language.
You say you don't want any halftones or shades. But screen-printing is about halftone films, in opposition to continuous tone films, isn't it? 

Good luck,


Stefan