QTR-Quadtone RIP

Hi Joost

It sounds to me like you have a pretty good grasp of the toner
concept. If I may use a very simplistic analogy, QTR is like a toolbox
with a number of tools. The grey, toner and toner 2 curves are like 3
wrenches. They are normally used for adjusting bolts. Sometimes you
need to pound a nail, and they will do that too. Maybe not as easily
as using a hammer, but you can make it work.

The three curves in QTR (grey, toner and toner 2) provide 3 parallel
means of partitioning the inks over the greyscale range. The top (or
leftmost) tab in the Curve Creation window assigns the inks to each of
these curves you want to use (as you are obviously aware, you don't
have to use them all). With each ink are parameters that define where
and how that ink fits into it's assigned curve over the tonal range
(i.e. the partitioning). For example, the density information for ink
influences where in the tonal range the ink is used. The limit
controls how much is used. The relative densities of each ink controls
the order of use of the inks assigned to that curve over the tonal range.

One interesting feature of QTR is that the partitioning is applied
even if an ink is limited to 0. So, for example, that means that you
can apply an ink A to the deep shadows by assigning  another
(otherwise unused) ink B position with a 0 limit and lower density
than the ink you want to use. The density value of this lower ink B
can be arbitrarily set to control where in the tonal range, Ink A
starts to come in. If you look at the curve for Ilford Smooth Pearl
warm or cool you'll see an example of this.

I haven't used the UT-3D inks or seen any curves, so I can't suggest
the "best" way to use QTR for this inkset. What ever way you decide to
proceed, sharing the results with with us all will help other get over
the hump you are climbing.

Tom Moore

--- In QuadtoneRIP@yahoogroups.com, "horstenj" <j.h.j.h@...> wrote:
>
> Hi all,
> 
> Since a few weeks I'm using the UT-3D inks on my 2100. I have 
> created some basic QTR curves for EEM. Basically I copied and re-
> linearized the UT7 cool and warm curves. Additionally, I made a 
> simple black-only curve and a "neutral" curve, Partly as an 
> exercise, partly since it allows spot-on neutral tones where the QTR 
> curve balance is a bit more guess work (50/50 is apparently cooler 
> than neutral on the slightly cool EEM). Partly I made this curve as 
> well to have a good starting point for the next step: the use of the 
> selenium/lab a/yellow position toner.
> 
> My question is the following. I do not grasp completely the concept 
> of a "toner" (there is another thread in which the original poster 
> has a similar problem). The lab a toner has essentially the same 
> density as the warm and cool LLK toners (LC and LM positions). So I 
> see the following options:
> 
> 1) discard the warm and cool LLK toners and use the lab a toner 
> instead as part of the "gray curves". I did this, works fine for the 
> midtone/higlights, but I feel there should be more tone in the 
> shadows.
> 
> 2) as 1) but reduce the ink limits for the warm and cool LK toners 
> (cyan and magenta positions), giving more "room" for the lab a 
> tonerin the shadows. I am in the midst of setting this up, but my 
> feeling is I will get insufficient shadow density.
> 
> 3) set up the ink set as a 2K system (Eboni as K, combination of 
> cyan and magenta positions as LK) and use the lab a toner not as LLK 
> but as "toner". 
> 
> 
> Is their a "best way" of proceeding? Or is it just a matter of 
> preference?
> 
> Joost
>