QTR-Quadtone RIP

Hi David,

Here is the text of my base profile for the P800:
___________________________________________________

#Notes - Base Profile for Pd using Pictorico TPS (Ultra)

PRINTER=QuadP800
CURVE_NAME=P800PK-UPOHP-Pd-Base
GRAPH_CURVE=YES

N_OF_INKS=8
DEFAULT_INK_LIMIT=60
BOOST_K=60
LIMIT_K=60
LIMIT_C=5
LIMIT_M=5
LIMIT_Y=12
LIMIT_LC=5
LIMIT_LM=5
LIMIT_LK=60
LIMIT_LLK=80

N_OF_GRAY_PARTS=3
GRAY_INK_1=K
GRAY_VAL_1=100
GRAY_INK_2=LK
GRAY_VAL_2=40
GRAY_INK_3=LLK
GRAY_VAL_3=10
GRAY_HIGHLIGHT=2
GRAY_SHADOW=6
GRAY_OVERLAP=

GRAY_GAMMA=0.8

GRAY_CURVE="0;0 100;100"

N_OF_UNUSED=0
COPY_CURVE_C=K
COPY_CURVE_M=K
COPY_CURVE_Y=K
COPY_CURVE_LC=LK
COPY_CURVE_LM=LK
________________________________________________________

If you want to try it out, copy and paste it into a text file, change Pd in the Curve Name to Kallitype or whatever you use as an abbreviation, save it in the appropriate QTR folder, then install it as you would any QTR curve. I expect it will print slightly contrasty. The next step will be to use the Gray Curve field to linearize the negative based on readings of the 21-step target that you can make using a scanner, densitometer, or spectrophotometer. (Listed in order from worst to best, IMHO.) 

Ian is obviously very accomplished at what he does, but I have to take issue with the idea of using only K, C, and Y. As someone else noted earlier in this thread, that is very likely to be the cause of your problems. In my experience, the LK and LLK inks are very useful along with K and Y. The other colors (C, M, LC, and LM) less so. 

Don't worry about all those other QTR functions that I mentioned. That is advanced stuff that is probably best left alone unless you happen to be someone who is more interesting in tinkering than making images.

Try this profile out to see if you still have the problem. If not, then the cause was the profile, and you can now move on to linearization. If yes, then the cause must lie elsewhere.

Cheers,
Keith

Keith Schreiber
jkschreiber.com




> On Nov 21, 2016, at 3:32 PM, David Aimone daimone@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:
> 
> 
> Keith,
> 
> I have not done Gray Curves, I am new to QTR.  I’ve used both curves or gradient maps in Photoshop with step tablets to create digital negatives without QTR.  I hope I’m understanding what you’re saying and making sense back!  So the following is still a mystery to me in regards to QTR:
> 
>> The only thing that would be different would be the Gray Curve, which would be customized to your process, and possibly the Gray Gamma setting. Gray Highlight, Gray Shadow, and Gray Overlap settings could also be modified, but I never have. 
> 
> 
> The only adaptations to Ian’s curve so far have been the ink limits for K, C and Y.  His file starts with ink limits of 40 for all three.  I get sufficient white lowering the limt to 25 for all three.  So I assume you are correct about "0;0 100;100" in the Gray Curve field. 
> 
> Seriously, I think I have a pretty good handle on the digital negative process but still a novice with how to apply and use QTR.
> 
> David Aimone
> david@aimonephoto.com <mailto:david@...>
> 
> http://www.aimonephoto.com <http://www.aimonephoto.com/>
> 
> 
>> On Nov 21, 2016, at 4:57 PM, Keith Schreiber keith@... <mailto:keith@...> [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com <mailto:QuadtoneRIP@yahoogroups.com>> wrote:
>> 
>> Hi David,
>> 
>> 
>> I'm using PiezoDN myself these days, but I used OEM inks with QTR on a 3880 (and a 3800 before that) for a long time. The profile I'm speaking of is for OEM inks on a P800. The bones of it are not much different than my base 3880 profile, but the results judging from the 2 negs that my friend sent me, are much better than I ever got from my 3880/OEM/QTR system. The only thing that would be different would be the Gray Curve, which would be customized to your process, and possibly the Gray Gamma setting. Gray Highlight, Gray Shadow, and Gray Overlap settings could also be modified, but I never have. 
>> 
>> What adaptations have you made to Ian's curve. What you posted on FB had "0;0 100;100" in the Gray Curve field. Do I guess correctly that that is Ian's profile unmodified?
>> 
>> Have you learned to make Gray Curves yet? Richard Boutwell has (or had?) a very nice spreadsheet for deriving the Gray Curve from a 21-step target. It converts from Density to Luminosity which results in a much more visually accurate linearization than a curve derived from Density values. I know Richard is working on a new and expanded version of his Digital Negative curve tool (which I am looking forward to) to compliment his recently released tools for inkjet printing. Here is a link to the older version which I think is still available: 
>> http://www.bwmastery.com/qtr-correction-curve-tool <http://www.bwmastery.com/qtr-correction-curve-tool>
>> 
>> As for my P800 profile, I suppose I could just paste the text here for you to copy/paste into a text file yourself, or I could send you the file directly. Your choice. As I said previously, it should at least help you to determine whether your problem lies with the profile or with the printer. 
>> 
>> For QTR settings, you should be using Ordered for the dither setting, 2880dpi, uni-directional, and Photo Black.
>> 
>> Cheers,
>> Keith
>> 
>>> On Nov 21, 2016, at 1:53 PM, daimone@... <mailto:daimone@...> [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com <mailto:QuadtoneRIP@yahoogroups.com>> wrote:
>>> 
>>> Keith,
>>> 
>>> 
>>> Sorry I didn't respond, I've been on and off FaceBook lately.  I'm new to QTR.  I would just load your curve into the first slot of the QTR print driver instead of the one adapted through Ian Leake's process?  Also, I am using OEM inks, just the QTR driver for printing, so I'm not sure your curve would be applicable?  As I said, new to QTR...
>>> 
>>> David
>>> 
>> 
>> 
> 
> 
>