QTR-Quadtone RIP

What you are seeing is not really metamerism.  Its just different color casts.
By using two different print drivers -- QTR and IP -- you are just
getting different
amounts of different inks being used in the prints.   I don't know
exactly what IP does
but in QTR the "warm" curves are just the black inks -- K, LK and LLK.    So the
greenish/yellow tinge you see is just the color of the Epson black inks.  The
idea in QTR is to blend different curves so you get the ink mix that
you personally
like.   There is no need to make custom curves.  Use the ones that are already
there.  Since I'm guessing you want a warmish print use the neutral, warm, and
sepia curves.   The sepia curves are a bit more reddish warm rather
than the warm
curves which are more yellowish warm.  Experiment to see what you like.
You might start with warm and then add in sepia to shift away from the greenish.
If it gets too warm for you substitute more neutral instead of warm.
Trying several small prints is really worth it.  Try extremes and then
narrow down
to what you like.

Roy

On Sat, Jun 4, 2011 at 9:29 AM, silverhound905
<digitalfineart@...> wrote:
> Thanks, Tyler, yes both images were printed on Epson Velvet Fine Art. Both images were printed using an Epson 3800 Pro, but one printed through QTR the other through IP. I've only used one curve ( Curve 1 UCmk-EVelvetFineArt-warm) with no curve blending as my understanding is that Curve Blending is only used for custom created curves (is this correct?) Advanced adjustments at default settings.
>
> One thing: Some of my ink levels were low and I'm wondering if this may have contributed to the colour shifting. Could this be the problem?
>
> --- In QuadtoneRIP@yahoogroups.com, "tboleyyh" <tyler@...> wrote:
>>
>> several things may apply, the first obvious question is whether or not the two prints were indeed the same paper, and if the two prints under a standard viewing system really do match in hue.
>> More probable though is ink build of the two systems. If paper and general hue are the same, then the ink rebuild in the QTR curves used have higher color ink component to black ink ratio, and the ImagePrint ink build uses more of the 3 k inks, and as little color ink as possible. THat would be my best guess and I've demonstrated the result many times myself working on monochromatic ink builds from OEM color with RIPS. Even how much LK and LK2 are used may give a slightly different metamerism failure result.
>> One way or another, the two ink builds are slightly different even if they result in similar hue, there are many ways to get there.
>> There is no doubt QTR could yield the same performance as ImagePrint in this regard, it's the same ink and paper. But you may have to learn how to tweak the curves yourself to maximize that particular issue. Usually it's not a problem, even though slight improvement is probably possible.
>> Tyler
>>
>>
>> --- In QuadtoneRIP@yahoogroups.com, "silverhound905" <digitalfineart@> wrote:
>> >
>> > I've recently started using QTR for printing monochrome prints and I'm finding that my prints suffer from a slight greenish/yellowish tinge when using the UCmk-EVelvetFineArt-warm curve. I'm using an Epson 3800.
>> > For the sake of comparison, I had a friend print the same images using ImagePrint and the prints did not show any noticeable color shifting.
>> > I'm not advanced enough yet to start creating my own curves, but I was wondering if there was anyway to minimize the metamerism using the QTR canned profiles.
>> >
>>
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-- 
Roy Harrington
roy@...
www.harrington.com