QTR-Quadtone RIP

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

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
>

--- In QuadtoneRIP@yahoogroups.com, "Tom Moore" <r.t.moore@...> 
wrote:
> It sounds to me like you have a pretty good grasp of the toner
> concept. 

I'm SLOWLY getting there ;-)

> 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. 

This is what I understand, I hope to get some more insight when to 
the wrench and when to use the hammer...
 
> 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 partly understood this, but you definitely give some new insights 
here.
 
> 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.

I have some first results now. I made (first versions of) the 
following basic curves (all for the 2100 on EEM):
- warm (relinearization of the UT7 curve)
- cool relinearization of the UT7 curve)
- black only
- neutral (an approx. 65/35% mix of warm and cool, making the 
midtones as neutral as possible)
Actually, these curves were pretty straightforward. 

More complicated are the curves involing the lab a/selenium toner. I 
tried the following:

- selenium 1: a K3 approach, Eboni for K, the neutral 65/35 
warm/cool mix as mentioned above for LK and the selenium/Lab a toner 
for LLK. So, the lab a toner is part of the gray curve. This is 
actually quite simple to make since the lab a toner has the same 
density as the warm & cool LLK toners. To me the disadvantage is 
that the shadows remain neutral and that only the higlights are 
toned.

- selenium 2: a "K3+toner" approach, with eboni, mix of warm & cool 
toners as K, LK and LLK + applying a QTR toner curve to the lab a 
toner. It is a bit more tricky to get this one right. I have 
something working now, with more tone in the shadows. Probably it 
can be better. But frankly, I don't know how to define "better" 
here. I can plot the a and b values over the range, but I'm not sure 
what an optimal plot should like like.

In addition, I made some split tone curves, mostly following the 
straightforward K3 approach as above, having either a warm or cool 
LK for the shadows and a warm, cool or selenium LLK toner for the 
highlights. I'm not too satisfied with these. The split tone effect 
is not very strong, since the tone of the shadows is much less clear 
than that of the higlight. To overcome this I am experimenting with 
two "cool2selenium" approaches:

- a K3+toner approach as above, but with pushing the selenium toner 
far to the highlights to leave some room for the cool LLK in the 
upper mid and lower higlights. 
- a "quasi K4" approach with for all toners as "grays": eboni for K, 
dark cool for LK, light cool for LLK and and selenium for LLLK 
(actually designed as LLK toner)

The first one works decently. I do not have a decent result with the 
second one. Since the densities of the LLK and LLLK toners are 
actually almost the same, I get a very sharp transition between cool 
and selenium. Based on Tom's suggestion I should perhaps 
artificially change the densities in the curve definition.

That's it till so far. Hope it is of any use to someone. Perhaps I 
am stating the obvious. Any suggestions are welcome!

Joost

--- In QuadtoneRIP@yahoogroups.com, "horstenj" <j.h.j.h@...> wrote:

> I am experimenting with 
> two "cool2selenium" approaches:
> 
> - a K3+toner approach as above, but with pushing the selenium toner 
> far to the highlights to leave some room for the cool LLK in the 
> upper mid and lower higlights. 
> - a "quasi K4" approach with for all toners as "grays": eboni for 
K, 
> dark cool for LK, light cool for LLK and and selenium for LLLK 
> (actually designed as LLK toner)
> 
> The first one works decently. I do not have a decent result with 
the 
> second one. Since the densities of the LLK and LLLK toners are 
> actually almost the same, I get a very sharp transition between 
cool 
> and selenium. Based on Tom's suggestion I should perhaps 
> artificially change the densities in the curve definition.

I played around a bit further with this "quasi K4" approach. And 
indeed, artificially changing the densities pulls the curves from one 
another and gives a smoother transition. But I think I like the first 
one better. Using the toner curve (i.s.o 4th K in the gray curve) 
allows for a much wider spread of selenium over the tonal range.

Another step in telling the wrench from the hammer ;-)

Joost