QTR companion file.acv

[cenotaphcorner]

Hi. Please could someone tell me how & why to install the appropriate companion file... in my case the QTR 2400. I have just printed off a PD test matrix and was quite pleased (actually very pleased) Trouble is that the highlights 010 are a little too bright.
Will installing this companion file solve my problem?
Tony Mc

 

[Ron-san]

Hi. Please could someone tell me how & why to install the appropriate companion file... in my case the QTR 2400. I have just printed off a PD test matrix and was quite pleased (actually very pleased) Trouble is that the highlights 010 are a little too bright.
Will installing this companion file solve my problem?
Tony Mc

Tony-- There are several possible ways to solve your problem, but first I need a bit more information.
Are you getting any print tone in the 0-10% highlights? If you are, and if you are happy with the rest of the print tones, then you just need a minor tweak. Take the step wedge test print that you have made (the one where you like everything but the 0-10% tones), scan it on a flat bed scanner, and measure the input/output vales using the Photoshop eyedropper as I describe in my book (or as is described in the article "Digital Negatives with the Epson 3800 printer and driver" that is downloadable from the Home page of my website, www.ronreeder.com . Use the input/output values to make a Photoshop .acv correction curve (described in the article) that you will then apply to the positive image file before inverting it to negative and printing with the QTR2400 profile you are currently using. This is a bit of a kludge since ideally you would go into the QTR profile and correct everything there. But if you only need a tweak, then doing it via a .acv correction curve applied to the positive image file is perhaps easier and gets the job done.

If you have no tone at all in the 0-10% highlights, then you need to either lower the contrast of your palladium emulsion or go into the QTR profile and lower the ink limits on one or more of the dark inks until you get the contrast of the negative adjusted to the contrast of your emulsion.

Let me know if any of this makes sense. Cheers, Ron reeder

 

[cenotaphcorner]

Ron— Thanks for your advice. I'm not getting any tone at all in steps 0-10% highlights. I'm already using straight lithium palladium emulsion with warm pot. oxalate developer. So without other measures e.g. raising the temp of the developer to the extreme, I do not know of any way to reduce the contrast of the sensitizer. Guess I'll have to lower the ink limits of the profile. Any advice on this, Ron? (I have a copy of your book)
Also, do I apply the companion curve for the R2400 to the positive image, then invert and print using the appropriate profile? Should I try this before making any revisions to the profile?

 

[Ron-san]

Ron Thanks for your advice. I'm not getting any tone at all in steps 0-10% highlights. I'm already using straight lithium palladium emulsion with warm pot. oxalate developer. So without other measures e.g. raising the temp of the developer to the extreme, I do not know of any way to reduce the contrast of the sensitizer. Guess I'll have to lower the ink limits of the profile. Any advice on this, Ron? (I have a copy of your book)
Also, do I apply the companion curve for the R2400 to the positive image, then invert and print using the appropriate profile? Should I try this before making any revisions to the profile?

Tony--To lower the contrast of your negative you will need to open the textfile for the QTR profile you are using. Then lower the ink limit for one or more or the dark inks. The most current instructions for doing this are in version 2 of the QTR manual that I have recently posted on my website, www.ronreeder.com.

I am not clear what you are calling a "companion curve" or where you got it from. Did no instructions come with it? At any rate, a companion curve of any sort is not the place where you want to alter the overall contrast of the negative. Do that by changing the dark ink limits. Cheers, Ron Reeder

 

[cenotaphcorner]

Ron— Many thanks for your reply. I do hope that I'm not tying your patience but would appreciate a little more help.
The companion curve was downloaded from Roy's site and is situated in the QTR Tools/QTR Install script folder. It is actually called: QTR 2400 Companion file.acv

The profile I'm using for my R2400 printer is the: 2400-K3mk-OHP-Pd.txt file.
Here is the print out of the text. Please could you give me an idea which variable to change first in order to get some tone in steps 0 to 10.

# QuadToneRIP curve descriptor file
#
# for R2400 with mK and LK k3 inks

PRINTER=QuadR2400
CALIBRATION=no
GRAPH_CURVE=yes

N_OF_INKS=8
DEFAULT_INK_LIMIT=85

LIMIT_K=
BOOST_K=0
LIMIT_C=0
LIMIT_M=0
LIMIT_Y=0
LIMIT_LC=0
LIMIT_LM=0
LIMIT_LK=
LIMIT_LLK=0

#
# Describe usage of each ink
# All inks must be listed
#

# Gray Partitioning Information

N_OF_GRAY_PARTS=2
GRAY_INK_1=K
GRAY_VAL_1=100

GRAY_INK_2=LK
GRAY_VAL_2=32.5

GRAY_INK_3=
GRAY_VAL_3=

GRAY_INK_4=
GRAY_VAL_4=

GRAY_INK_5=
GRAY_VAL_5=

GRAY_INK_6=
GRAY_VAL_6=

GRAY_INK_7=
GRAY_VAL_7=

GRAY_HIGHLIGHT=0
GRAY_SHADOW=10

GRAY_GAMMA=1.1
GRAY_CURVE="0;0 2;10 7;20 24;40 56;60 88;80 96;88 98;93 100;100"

Many thanks—Tony Mc

 

[Ron-san]

Ron

The profile I'm using for my R2400 printer is the: 2400-K3mk-OHP-Pd.txt file.
Here is the print out of the text. Please could you give me an idea which variable to change first in order to get some tone in steps 0 to 10.

Many thanksTony Mc

Tony--

Sending the QTR profile clarifies several things. First, I do not know what Roy was trying to accomplish with his companion file. But I think you do not need it. If you are happy with what this profile is doing, except for the highlight clipping that is occurring, you do not need any companion file.

Right now the profile is written so that only two inks are printing, K and LK (and I hope you are using matte black as the K ink). All the other inks are turned off. Second, the individual ink limits for the K and LK inks are left blank which means that they are both being controlled by the Default Ink Limit (ie, both K and LK are printing at 85% of maximum).

To decrease contrast of the negative you need to lower the limit of the K ink. To do this just type in some number after LIMIT_K= . Use a number that is lower than the 85% which is the current default setting. This lower number will now control the K ink, you will get a less contrasty negative, and by trying various numbers you ought to find a setting that will give just the highlight tone you are looking for.

The LK ink will still be set at 85 because you left its individual limit blank and it is therefore controlled by the Default Ink Limit.

Let me know if this works for you. Cheers, Ron Reeder

 

[cenotaphcorner]

RonMany thanks for your help. It's certainly allowed me to get somewhere near.