2014-02-27 by peteralan photography
Hallo
I'm an avid listener and very occasional contributor to this forum with a particular interest in
carbon transfer and photogravure printing. I'm undertaking some research on the UV
wavelength sensitivity of photosensitive coatings and the 'blocking characteristics' of various
inks and ink sets.
In case it is of interest to practitioners, I show below three graphs of the UV transmission
characteristics of PhotoBlack, Magenta, Cyan and Yellow inks printed as a QTR calibration
on Pictorico TPF100 through an Epson 3800 using Ultrachrome K3 inks. I also show the
transmission graph for the un-inked Pictorico substrate. I was surprised by the high levels of
absorption at mid-300nm wavelengths of all the inks and I'm having fun trying to compare
apples and pears and relate these data with the results from
X-rite 361T UV transmission
density measurements, also shown.
regards
Peter Moseley
(Please excuse the cross-posting on the Carbon and Alt-photo forums)
2014-02-28 by <beefyzee@...>
Hi Pete,
can't see those graphs anywhere (I absolutely hate this new Yahoo Groups design) but I'm quite interested to know how different inks block UV.
My interest is because I'll be using QTR to make circuit boards and the less ink I have to lay down the better edge quality I can get on my transparencies.
The screenprinting guys that do T-shirts use special fast drying high opacity black inks, purposely made to block UV. I just made a tiny little circuit board and the ink was nothing more than the stock standard dye ink the my Epson TX810FW uses. I used black only but I've heard yellow is very good at blocking UV. Using just the one transparency (i.e. not 2 stacked) and exposed my circuit board for 3 mins (instructions say max of 90 seconds) and the board suffered no exposure where the ink was blocking it.
Keith.
2014-02-28 by Lutsky, Berel
Also interested in seeing the data in a more meaningful format - have you posted this to a website somewhere that allows meaningful communication?
Berel Lutsky
Associate Professor of Art
UW Manitowoc
920-683-4735
2014-02-28 by Keith Schreiber
FWIW, I view this and other Yahoo groups via email and I did get the graphs. Seems some groups allow attachments while others don't. Not sure how this relates to viewing via Yahoo.
Another Keith
Hi Pete,
can't see those graphs anywhere (I absolutely hate this new Yahoo Groups design) but I'm quite interested to know how different inks block UV.
My interest is because I'll be using QTR to make circuit boards and the less ink I have to lay down the better edge quality I can get on my transparencies.
The screenprinting guys that do T-shirts use special fast drying high opacity black inks, purposely made to block UV. I just made a tiny little circuit board and the ink was nothing more than the stock standard dye ink the my Epson TX810FW uses. I used black only but I've heard yellow is very good at blocking UV. Using just the one transparency (i.e. not 2 stacked) and exposed my circuit board for 3 mins (instructions say max of 90 seconds) and the board suffered no exposure where the ink was blocking it.
Keith.
2014-03-03 by David Kachel
Peter,
I am just recently getting started with photogravure, direct to plate,
myself.
From what I have read, you may be testing the wrong inks.
It is my understanding that the inks to use are Matte Black, Yellow, Light
Black and Cyan, in that order, for descending effectiveness at blocking UV.
Some suggest throwing in Magenta as kind of an afterthought as a light ink.
I have found it an unnecessary waste of ink.
Considering how green I am at this, I have had pretty good results with
those four inks (K, Y, LtK, C).
If you do more testing, I would be interested to see those numbers.
BTW, your graphs didn't come through in my email either. And I can't even
respond on the forum itself. I guess Yahoo will get it sorted out
eventually.
David Kachel
___________________
Artist-Photographer
Fine B&W Photographs
www.davidkachel.com
david@...
Gallery:
www.reddoorfinephotographs.com
director@...
PO Box 1893
Alpine, TX 79831
(432) 386-5787
2014-03-03 by Ernst Dinkla
The choice of an ink for an alternative photo process can be quite
different to the choice of ink for blocking masks like used in PCB
processes or line and halftone printing in silkscreen. For example the
optional HP Z3200 media preset for alternative photo process films uses
the green ink mainly as it modulates the opacity for UV better than the
more opaque black ink would do.
--
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.
2014-03-04 by <sanking@...>
Selecting inks for use in a QTR profile for alternative printing with UV processes definitely must have other considerations than those used in line or halftone printing in silkscreen. It is also quite different than the requirements for making monochrome inkjet prints on paper. I am attaching a table that shows the UV readings of the K3 inks on Pictorico, as measured with a UV densitometer at 25%, 50%, 75% and 100%.
Sandy
Measurement of UV densities with Gretag D200-II
Center Bandwith 373
nm
Ink Pattern Page - Printed Calibration Mode
Pictorico Premium OHP
Base density of substrate subtracted from readings
Epson Ultrachrome K3
Epson R3000
25%
50%
75%
100%
Cyan
.81
1.27
1.69
1.97
Magenta
.26
.39
.57
.69
Yellow
.75
1.22
1.74
2.16
Photo Black
.73
1.25
1.88
2.34
Light Cyan
.35
.53
.74
.89
Light Magenta
.11
.18
.24
.30
Light Black
.45
.73
1.07
1.35
Light Light Black
.20
.31
.43
.53
2014-03-04 by David Kachel
Selecting inks for use in a QTR profile for alternative printing with UV
processes definitely must have other considerations than those used in line
or halftone printing in silkscreen. It is also quite different than the
requirements for making monochrome inkjet prints on paper. I am attaching a
table that shows the UV readings of the K3 inks on Pictorico, as measured
with a UV densitometer at 25%, 50%, 75% and 100%.
Thanks,
I couldn't help but notice that Matte Black is missing. Isn't it the best UV
blocker of the lot?
David Kachel
___________________
Artist-Photographer
Fine B&W Photographs
www.davidkachel.com
david@...
Gallery:
www.reddoorfinephotographs.com
director@...
PO Box 1893
Alpine, TX 79831
(432) 386-5787
2014-03-04 by <sanking@...>
Yes, MK has the highest UV blocking of any of the inks in a K3 set. If I had included it the measurement would have been about log 3.5 at 100%. The reason I did not include it is because for making digital negatives for alternative printing most people do not use it in their profiles because its density is out of line with the other three major UV blockers, Cyan, Yellow and Light Black. If you notice, at the useful level of about 25% PK, C and Y are about equal UV blockers, and if we use LK at about 45% - 50% we have four inks that block about the same. This is good for smoothness in a digital negative, at least that is what I have found.
In other words, the very high UV blocking is not usually considered a plus profiling for digital negatives with alternative printing since it is somewhat overkill for the job.
Sandy
2014-03-04 by David Kachel
Yes, MK has the highest UV blocking of any of the inks in a K3 set. If I had
included it the measurement would have been about log 3.5 at 100%. The
reason I did not include it is because for making digital negatives for
alternative printing most people do not use it in their profiles because its
density is out of line with the other three major UV blockers, Cyan, Yellow
and Light Black. If you notice, at the useful level of about 25% PK, C and Y
are about equal UV blockers, and if we use LK at about 45% - 50% we have
four inks that block about the same. This is good for smoothness in a
digital negative, at least that is what I have found.
In other words, the very high UV blocking is not usually considered a plus
profiling for digital negatives with alternative printing since it is
somewhat overkill for the job.
Then,
Do I assume correctly that you are using the same curve for all four inks,
rather than trying to stairstep them as might be done in a normal B&W
printing ink set?
I am making direct to plate gravure plates on PETG plastic, BTW, so it is
somewhat different. My problem is, I don't know how different?!@
Would you mind sending me a sample QTR profile? DTP requires far less ink
than internegs or it puddles and flows all over the place, but I imagine
proportions would be similar.
I made some fairly nice prints, considering they are a beginner's tests,
today, but I can see my profile is wrong. There is some tone crossover
between upper midtones and highlights.
The big problem with what I am doing is that the inks remain completely wet
on the plate and are simply washed away when the plate is processed. This
makes measurement difficult at best.
David Kachel
___________________
Artist-Photographer
Fine B&W Photographs
www.davidkachel.com
david@...
Gallery:
www.reddoorfinephotographs.com
director@...
PO Box 1893
Alpine, TX 79831
(432) 386-5787
2014-03-04 by <sanking@...>
David,
Correct, I am using a single gray value system. See below. The profile that I use for carbon printing is attached. I used LINEARIZE to adjust input/output but you could do the same thing with GRAY-CURVE =.
In the past I used a two or three gray value system similar to what Ron Reeder teaches, but last year I switched to a single gray value system after discussions with a Chapel Hill based photographer named Mike Rosenberg. I find the single gray value system much easier to understand and adjust with consistency than the multi gray value method. This profile most likely will give more density range than you need for gravure, but it is easy to lower the DR by reducing the Level numbers of the UV blockers. After I introduced this method of profiling with the K3 inks on my carbon forum several people adopted with the comment that they found it much easier to work with than multi-gray value methods.
Sandy
#PRINTER=QuadR3000
#CURVE_NAME= Carbon100 #Based on Carbon Tissue #222, 16 grams of Black Cat Ink with tissue coated to a wet height of 0.9mm.
#Profile when printing a step wedge gives a DR (density range) of approximately log 2.50.
#With Tissue #222 sensitize with a 8% potassium dichromate solution, diluted 1+1 with acetone, approximately 10 ml per 8X10 sheet, applied in two coatings with a roller. 350 ULF units.
GRAPH_CURVE=YES
N_OF_INKS=8
DEFAULT_INK_LIMIT=55
LIMIT_K=25
LIMIT_C=25
LIMIT_M=1
LIMIT_Y=25
LIMIT_LC=1
LIMIT_LM=1
LIMIT_LK=25
LIMIT_LLK=1
GRAY_HIGHLIGHT=4
GRAY_SHADOW=4
GRAY_GAMMA= 1
CURVE_K= "0;0 100;100"
COPY_CURVE_C=K
COPY_CURVE_M=K
COPY_CURVE_Y=K
COPY_CURVE_LC=K
COPY_CURVE_LM=K
COPY_CURVE_LK=K
COPY_CURVE_LLK=K
LINEARIZE= "14.68 16.7 19.53 22.66 26.41 30.65 34.9 39.36 44.29 48.97 54.62 59.42 63.5 68.13 73.27 77.56 81.13 85.78 89.04 93.05 94.62"
2014-03-05 by Kerik Kouklis
Sandy,
This is very interesting! Do you have a similar profile for a 3880 or would you simply use these same values? Do you have a profile for palladium you would share? Also I see your not using any black boost?
Thanks,
-Kerik
Show quoted textHide quoted text
> On Mar 4, 2014, at 3:57 PM, <sanking@...> wrote:
>
> David,
>
> Correct, I am using a single gray value system. See below. The profile that I use for carbon printing is attached. I used LINEARIZE to adjust input/output but you could do the same thing with GRAY-CURVE =.
> In the past I used a two or three gray value system similar to what Ron Reeder teaches, but last year I switched to a single gray value system after discussions with a Chapel Hill based photographer named Mike Rosenberg. I find the single gray value system much easier to understand and adjust with consistency than the multi gray value method. This profile most likely will give more density range than you need for gravure, but it is easy to lower the DR by reducing the Level numbers of the UV blockers. After I introduced this method of profiling with the K3 inks on my carbon forum several people adopted with the comment that they found it much easier to work with than multi-gray value methods.
>
> Sandy
>
> #PRINTER=QuadR3000
> #CURVE_NAME= Carbon100 #Based on Carbon Tissue #222, 16 grams of Black Cat Ink with tissue coated to a wet height of 0.9mm.
> #Profile when printing a step wedge gives a DR (density range) of approximately log 2.50.
> #With Tissue #222 sensitize with a 8% potassium dichromate solution, diluted 1+1 with acetone, approximately 10 ml per 8X10 sheet, applied in two coatings with a roller. 350 ULF units.
>
> GRAPH_CURVE=YES
> N_OF_INKS=8
> DEFAULT_INK_LIMIT=55
>
> LIMIT_K=25
> LIMIT_C=25
> LIMIT_M=1
> LIMIT_Y=25
> LIMIT_LC=1
> LIMIT_LM=1
> LIMIT_LK=25
> LIMIT_LLK=1
>
> GRAY_HIGHLIGHT=4
> GRAY_SHADOW=4
> GRAY_GAMMA= 1
>
> CURVE_K= "0;0 100;100"
> COPY_CURVE_C=K
> COPY_CURVE_M=K
> COPY_CURVE_Y=K
> COPY_CURVE_LC=K
> COPY_CURVE_LM=K
> COPY_CURVE_LK=K
> COPY_CURVE_LLK=K
>
> LINEARIZE= "14.68 16.7 19.53 22.66 26.41 30.65 34.9 39.36 44.29 48.97 54.62 59.42 63.5 68.13 73.27 77.56 81.13 85.78 89.04 93.05 94.62"
>
>
2014-03-05 by David Kachel
After I introduced this method of profiling with the K3 inks on my carbon
forum several people adopted with the comment that they found it much easier
to work with than multi-gray value methods.
Please, will you be so kind as to direct me to what you or others have
written on the subject?
On another note, today I printed the same plate on eight different papers,
just because I had the paper and the time, and wanted to see what difference
papers would make.
I was surprised to find how very similar the prints looked and how much
easier than I had anticipated it was to ink a plate consistently from one
print to the next. The curve is still steep, but I'm makin' progress.
David Kachel
___________________
Artist-Photographer
Fine B&W Photographs
www.davidkachel.com
david@...
Gallery:
www.reddoorfinephotographs.com
director@...
PO Box 1893
Alpine, TX 79831
(432) 386-5787
2014-03-05 by David Kachel
GRAPH_CURVE=YES
N_OF_INKS=8
DEFAULT_INK_LIMIT=55
LIMIT_K=25
I forgot to ask\u2026
That is K and not PK, correct?
David Kachel
___________________
Artist-Photographer
Fine B&W Photographs
www.davidkachel.com
david@...
Gallery:
www.reddoorfinephotographs.com
director@reddoorfinephotographs.com
PO Box 1893
Alpine, TX 79831
(432) 386-5787
2014-03-05 by <sanking@...>
Hi Kerik,
The profile should print on the 3800/3880 with QTR almost the same as it prints with the R3000. I use the same profile, with just a minor adjustment, LK = 40 instead of LK = 25 on the 7800 and the resulting DR and linearization is almost identical with both printers. Carbon is very straight line compared to the long toe and shoulder of palladium so you may need to adjust GRAY-GAMMA to less than 1 to optimize.
For platinum printing, assuming you print with almost pure palladium, the DR of this profile, which is about 2.5, should be fairly close to optimum. But if you need to adjust it up or down it is easy to do, just increase the Level of the K, C, Y and LK inks to get more density, decrease the Level for less density. And change the inks more or less proportionally to avoid confusion. Leave the low UV blockers as is, they don't matter anyway in a single gray system.
As for K boost, I don't use it and I think you will find need it with this profile. After you nail down the DR just use Eisenlord's Build QTR script, print a step wedge and create your correction curve.
If you try this and find a problem please point it out. I am still new to this method and like it so much I may have missed something important.
Sandy
2014-03-05 by <sanking@...>
Kerik,
I garbled the language with my reply. I meant to say that I don't believe you will need the K boost with the single gray value method of profiling. You should be able to tell with a few tests.
David,
Yes, I am using PK in the profile. Not much has been said about this method for digital negatives. As I mentioned, I got the idea from Mike Rosenberg (www.mprosenberg.com), who was using it for silver, I adapted it to carbon printing, and discussed it on the carbon forum on yahoo in a thread called QTR 101.
Sandy
2014-03-05 by David Kachel
Yes, I am using PK in the profile. Not much has been said about this method
for digital negatives. As I mentioned, I got the idea from Mike Rosenberg
(www.mprosenberg.com), who was using it for silver, I adapted it to carbon
printing, and discussed it on the carbon forum on yahoo in a thread called
QTR 101.
Odd coincidence. I downloaded Mike's paper just a couple of days ago, but
hadn't gotten around to reading it yet.
If you were going to use MK, how would you adapt the profile? (I never,
ever, use PK for anything and would prefer to avoid having to waste ink
switching over and back again for a single purpose.)
Earlier you said: "I used LINEARIZE to adjust input/output but you could do
the same thing with GRAY-CURVE =."
Would you expand on that? I don't quite follow how gray curve can substitute
for linearization.
David Kachel
___________________
Artist-Photographer
Fine B&W Photographs
www.davidkachel.com
david@...
Gallery:
www.reddoorfinephotographs.com
director@...
PO Box 1893
Alpine, TX 79831
(432) 386-5787
2014-03-05 by <sanking@...>
"If you were going to use MK,
how would you adapt the profile? (I never, ever, use PK for anything and
would prefer to avoid having to waste ink switching over and back again
for a single purpose.)"
You would need to find a percentage (Level) for MK that matches more or less the UV blocking of C and Y. In my profile, where the K = PK, the current values are K=25, Y=25 and C=25, and they all have about the same UV blocking. If I were to substitute MK for PK it would be necessary to lower the MK percentage to somewhere between 5-10 because MK is a much more powerful UV blocker.
"Would you expand on that? I don't quite follow how gray curve can substitute for linearization."
Both LINEARIZE and GRAY-CURVE= are methods for equalizing input (ink) and output (process) tonal values. They are different but work about the same with digital negatives. So, in my profile, instead of the LINEARIZE routine I could equalize input/output with a curve. Like this,
Instead of,
CURVE_K= "0;0 100;100"
I could equalize input/output with, CURVE_K= "0;0 4;10 8;18 13;29 20;41 28;51 32;56 37;60 42;65 48;70 55;75 63;80 73;85 84;90 92;95 100;100"
Sandy
2014-03-05 by David Kachel
You would need to find a percentage (Level) for MK that matches more or less
the UV blocking of C and Y. In my profile, where the K = PK, the current
values are K=25, Y=25 and C=25, and they all have about the same UV
blocking. If I were to substitute MK for PK it would be necessary to lower
the MK percentage to somewhere between 5-10 because MK is a much more
powerful UV blocker.
So, K=10, Y=25, C=25, LK=25. Like that?
Thank you very much for your help, BTW. If this works, it is a lot simpler
than what I have been doing.
David Kachel
___________________
Artist-Photographer
Fine B&W Photographs
www.davidkachel.com
david@...
Gallery:
www.reddoorfinephotographs.com
director@...
PO Box 1893
Alpine, TX 79831
(432) 386-5787
2014-03-05 by <sanking@...>
"So, K=10, Y=25, C=25, LK=25. Like that?"
Yes, just like that.
After you install the profile have a look at the curve in .quad view and it will be clear why it is so easy to adjust with some idea what will happen. I have been making digital negatives with QTR for almost ten years and this is by far the easiest method to understand, and explain, I have found.
Sandy
2014-03-05 by Kerik Kouklis
Sandy,
OK, thanks. I’m working on it. A couple more questions. What do your negs look like? Are they quite green? Also, with the profile you gave, do you know what the approximate UV density of the 100% value on a stepwedge is?
Kerik
Show quoted textHide quoted text
From: QuadtoneRIP@yahoogroups.com [mailto:QuadtoneRIP@yahoogroups.com] On Behalf Of sanking@...
Sent: Tuesday, March 04, 2014 5:09 PM
To: QuadtoneRIP@yahoogroups.com
Subject: [QuadtoneRIP] RE: UV transmisison characteristics of Epson K3 inks
Hi Kerik,
The profile should print on the 3800/3880 with QTR almost the same as it prints with the R3000. I use the same profile, with just a minor adjustment, LK = 40 instead of LK = 25 on the 7800 and the resulting DR and linearization is almost identical with both printers. Carbon is very straight line compared to the long toe and shoulder of palladium so you may need to adjust GRAY-GAMMA to less than 1 to optimize.
For platinum printing, assuming you print with almost pure palladium, the DR of this profile, which is about 2.5, should be fairly close to optimum. But if you need to adjust it up or down it is easy to do, just increase the Level of the K, C, Y and LK inks to get more density, decrease the Level for less density. And change the inks more or less proportionally to avoid confusion. Leave the low UV blockers as is, they don't matter anyway in a single gray system.
As for K boost, I don't use it and I think you will find need it with this profile. After you nail down the DR just use Eisenlord's Build QTR script, print a step wedge and create your correction curve.
If you try this and find a problem please point it out. I am still new to this method and like it so much I may have missed something important.
Sandy
[Non-text portions of this message have been removed]
2014-03-05 by peteralan photography
These are my equivalent measurements (again, substracting the substrate density). Some interesting differences compard with Sandy's figures:
Epson 3800 printed on Pictorico TPF 100 measured with X-rite 361T
QTR QTR QTR QTR QTR
% Photo Black Light Black Yellow Magenta Cyan
25 1.05 0.62 1.31 0.31 0.61
50 1.85 1.01 2.17 0.51 0.93
75 2.52 1.34 2.68 0.65 1.15
100 3.02 1.54 2.94 0.76 1.32
regards
Peter
________________________________
Show quoted textHide quoted text
From: "sanking@..." <sanking@...>
To: QuadtoneRIP@yahoogroups.com
Sent: Tuesday, 4 March 2014, 21:45
Subject: Re: [QuadtoneRIP] UV transmisison characteristics of Epson K3 inks
Selecting inks for use in a QTR profile for alternative printing with UV processes definitely must have other considerations than those used in line or halftone printing in silkscreen. It is also quite different than the requirements for making monochrome inkjet prints on paper. I am attaching a table that shows the UV readings of the K3 inks on Pictorico, as measured with a UV densitometer at 25%, 50%, 75% and 100%.
Sandy
Measurement of UV densities with Gretag D200-II Center Bandwith 373 nm Ink Pattern Page - Printed Calibration Mode Pictorico Premium OHP Base density of substrate subtracted from readings
Epson Ultrachrome K3 Epson R3000
25%
50%
75%
100%
Cyan
.81
1.27
1.69
1.97
Magenta
.26
.39
.57
.69
Yellow
.75
1.22
1.74
2.16
Photo Black
.73
1.25
1.88
2.34
Light Cyan
.35
.53
.74
.89
Light Magenta
.11
.18
.24
.30
Light Black
.45
.73
1.07
1.35
Light Light Black
.20
.31
.43
.53
2014-03-05 by <sanking@...>
Kerik,
The color of the negatives should be green. The Y and C gives green, and PK and LK merely darken the green.
I read a maximum density (through) Pictorico of about log 2.80 at 100%. The Pictorico base has a UV blocking of about log 2.3, so 2.80 - .23 gives a density range of about 2.57.
Sandy
2014-03-05 by <sanking@...>
Peter,
I added readings to the chart for the Epson 7800 so you can see them side by side with the R3000. As you can tell, there are a few significant differences between the two printers at 100%, but at 25% not so much. In the table the top row of density values is for the 7800, the bottom row the R3000.
Sandy
Measurement of UV densities with Gretag D200-II
Center Bandwith 373
nm
Ink Pattern Page - Printed Calibration Mode
Pictorico Premium OHP
Base density of substrate subtracted from readings
Epson Ultrachrome K3
7800
R3000
25%
50%
75%
100%
Cyan
.71
.81
1.33
1.27
1.74
1.69
2.02
1.97
Magenta
.27
.26
.47
.39
.64
.57
.72
.69
Yellow
.76
.75
1.51
1.22
2.1
1.74
2.63
2.16
Photo Black
.74
.73
1.48
1.25
2.13
1.88
2.7
2.34
Light Cyan
.32
.35
.55
.53
.76
.74
.89
.89
Light Magenta
.11
.11
.16
.18
.25
.24
.30
.30
Light Black
.45
.45
.84
.73
1.20
1.07
1.50
1.35
Light Light Black
.19
.20
.33
.31
.46
.43
.56
.53
2014-03-05 by David Kachel
I just realized there is no Gray Parts data here. Shouldn't that be here too?
TIA
David,
Correct, I am using a single gray value system. See below. The profile that I use for carbon printing is attached. I used LINEARIZE to adjust input/output but you could do the same thing with GRAY-CURVE =.
In the past I used a two or three gray value system similar to what Ron Reeder teaches, but last year I switched to a single gray value system after discussions with a Chapel Hill based photographer named Mike Rosenberg. I find the single gray value system much easier to understand and adjust with consistency than the multi gray value method. This profile most likely will give more density range than you need for gravure, but it is easy to lower the DR by reducing the Level numbers of the UV blockers. After I introduced this method of profiling with the K3 inks on my carbon forum several people adopted with the comment that they found it much easier to work with than multi-gray value methods.
Sandy
#PRINTER=QuadR3000
#CURVE_NAME= Carbon100 #Based on Carbon Tissue #222, 16 grams of Black Cat Ink with tissue coated to a wet height of 0.9mm.
#Profile when printing a step wedge gives a DR (density range) of approximately log 2.50.
#With Tissue #222 sensitize with a 8% potassium dichromate solution, diluted 1+1 with acetone, approximately 10 ml per 8X10 sheet, applied in two coatings with a roller. 350 ULF units.
GRAPH_CURVE=YES
N_OF_INKS=8
DEFAULT_INK_LIMIT=55
LIMIT_K=25
LIMIT_C=25
LIMIT_M=1
LIMIT_Y=25
LIMIT_LC=1
LIMIT_LM=1
LIMIT_LK=25
LIMIT_LLK=1
GRAY_HIGHLIGHT=4
GRAY_SHADOW=4
GRAY_GAMMA= 1
CURVE_K= "0;0 100;100"
COPY_CURVE_C=K
COPY_CURVE_M=K
COPY_CURVE_Y=K
COPY_CURVE_LC=K
COPY_CURVE_LM=K
COPY_CURVE_LK=K
COPY_CURVE_LLK=K
LINEARIZE= "14.68 16.7 19.53 22.66 26.41 30.65 34.9 39.36 44.29 48.97 54.62 59.42 63.5 68.13 73.27 77.56 81.13 85.78 89.04 93.05 94.62"
2014-03-05 by <sanking@...>
David,
There is only one single part, all of the curves follow the K with the COPY_CURVE= command.
Sandy
2014-03-05 by David Kachel
David,
There is only one single part, all of the curves follow the K with the
COPY_CURVE= command.
N_OF_GRAY_PARTS=1
GRAY_INK_1=K
GRAY_VAL_1=100
Is that correct?
I ran on plate like that. It was waaaaaay overexposed!
David Kachel
___________________
Artist-Photographer
Fine B&W Photographs
www.davidkachel.com
david@...
Gallery:
www.reddoorfinephotographs.com
director@...
PO Box 1893
Alpine, TX 79831
(432) 386-5787
2014-03-05 by David Kachel
Sorry,
I meant to say, "underexposed".
David Kachel
___________________
Artist-Photographer
Fine B&W Photographs
www.davidkachel.com
david@...
Gallery:
www.reddoorfinephotographs.com
director@...
PO Box 1893
Alpine, TX 79831
(432) 386-5787
2014-03-05 by David Kachel
BINGO!
Never mind\u2026
Lesson learned: do not attempt to read instructions while standing on your head.
I set all four inks to 10 and away I went. Not a wonderful plate, but now I know how to proceed. Looks like a K boost will be beneficial for DTP photogravure.
The four inks together really are very near radiation proof!
Thanks to sanking and everyone else. The grain is dramatically reduced and my crossover problem appears to be gone.
Going to make a quick print now to be sure.
David Kachel
___________________
Artist-Photographer
Fine B&W Photographs
www.davidkachel.com
david@...
Gallery:
www.reddoorfinephotographs.com
director@...
PO Box 1893
Alpine, TX 79831
(432) 386-5787
2014-03-10 by Alan Vlach
Roy,
Chartthrob has a new function to create a negative curve. It is applied to a positive image and inverts it while applying the curve. I plugged this curve into a QTR profile and didn't get what I was expecting.
Anyway, I created this curve using the chartthrob negative function:
I created this QTR profile using the above curve:
# QuadToneRIP curve descriptor file
#
# PRINTER=QUAD3800 Salted Paper
# TPF100 Ink limit =100
PRINTER=QUAD3800
CALIBRATION=no
GRAPH_CURVE=yes
N_OF_INKS=8
DEFAULT_INK_LIMIT=100
LIMIT_K=35
#BOOST_K=80
LIMIT_C=35
LIMIT_M=1
LIMIT_Y=35
LIMIT_LC=1
LIMIT_LM=1
LIMIT_LK=35
LIMIT_LLK=1
# Describe usage of each ink
# All inks must be listed
# Gray Partitioning Information
N_OF_GRAY_PARTS=1
GRAY_INK_1=K
GRAY_VAL_1=100
GRAY_INK_2=
GRAY_VAL_2=
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_INK_8=
GRAY_VAL_8=
GRAY_HIGHLIGHT=0
GRAY_SHADOW=0
GRAY_GAMMA=1.5
GRAY_CURVE=/Users/windeking/Desktop/Curves/Chartthrobnegtest.acv
COPY_CURVE_C=K
COPY_CURVE_M=K
COPY_CURVE_Y=K
COPY_CURVE_LC=K
COPY_CURVE_LM=K
COPY_CURVE_LK=K
COPY_CURVE-LLK=K
And printed this step wedge:
I expected to get this result:
But this is what printed:
As you can see the 0% or 255 value printed white instead of black. The gradient at the top of the wedge showed the darks printing till the very end where it printed white again.
I opened the step wedge in photoshop and applied a levels layer which changed the output value from 255 to 254:
I printed this image and got the expected result.
I'm also curious about the choppy look on the right hand side of the gradient.
Thanks for all your help,
Alan
2014-03-10 by yashasvi.bhuta@yahoo.com
Is there a new chart throb application. If than can ypu please give a link for it.
Sent from Yahoo Mail on Android
Show quoted textHide quoted text
From:
Alan Vlach ;
To:
;
Subject:
Re: [QuadtoneRIP] UV transmisison characteristics of Epson K3 inks
Sent:
Mon, Mar 10, 2014 3:07:11 PM
Roy,
Chartthrob has a new function to create a negative curve. It is applied to a positive image and inverts it while applying the curve. I plugged this curve into a QTR profile and didn't get what I was expecting.
Anyway, I created this curve using the chartthrob negative function:
I created this QTR profile using the above curve:
# QuadToneRIP curve descriptor file
#
# PRINTER=QUAD3800 Salted Paper
# TPF100 Ink limit =100
PRINTER=QUAD3800
CALIBRATION=no
GRAPH_CURVE=yes
N_OF_INKS=8
DEFAULT_INK_LIMIT=100
LIMIT_K=35
#BOOST_K=80
LIMIT_C=35
LIMIT_M=1
LIMIT_Y=35
LIMIT_LC=1
LIMIT_LM=1
LIMIT_LK=35
LIMIT_LLK=1
# Describe usage of each ink
# All inks must be listed
# Gray Partitioning Information
N_OF_GRAY_PARTS=1
GRAY_INK_1=K
GRAY_VAL_1=100
GRAY_INK_2=
GRAY_VAL_2=
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_INK_8=
GRAY_VAL_8=
GRAY_HIGHLIGHT=0
GRAY_SHADOW=0
GRAY_GAMMA=1.5
GRAY_CURVE=/Users/windeking/Desktop/Curves/Chartthrobnegtest.acv
COPY_CURVE_C=K
COPY_CURVE_M=K
COPY_CURVE_Y=K
COPY_CURVE_LC=K
COPY_CURVE_LM=K
COPY_CURVE_LK=K
COPY_CURVE-LLK=K
And printed this step wedge:
I expected to get this result:
But this is what printed:
As you can see the 0% or 255 value printed white instead of black. The gradient at the top of the wedge showed the darks printing till the very end where it printed white again.
I opened the step wedge in photoshop and applied a levels layer which changed the output value from 255 to 254:
I printed this image and got the expected result.
I'm also curious about the choppy look on the right hand side of the gradient.
Thanks for all your help,
Alan
2014-03-10 by Alan Vlach
Show quoted textHide quoted text
Roy,
Chartthrob has a new function to create a negative curve. It is applied to a positive image and inverts it while applying the curve. I plugged this curve into a QTR profile and didn't get what I was expecting.
Anyway, I created this curve using the chartthrob negative function:
I created this QTR profile using the above curve:
# QuadToneRIP curve descriptor file
#
# PRINTER=QUAD3800 Salted Paper
# TPF100 Ink limit =100
PRINTER=QUAD3800
CALIBRATION=no
GRAPH_CURVE=yes
N_OF_INKS=8
DEFAULT_INK_LIMIT=100
LIMIT_K=35
#BOOST_K=80
LIMIT_C=35
LIMIT_M=1
LIMIT_Y=35
LIMIT_LC=1
LIMIT_LM=1
LIMIT_LK=35
LIMIT_LLK=1
# Describe usage of each ink
# All inks must be listed
# Gray Partitioning Information
N_OF_GRAY_PARTS=1
GRAY_INK_1=K
GRAY_VAL_1=100
GRAY_INK_2=
GRAY_VAL_2=
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_INK_8=
GRAY_VAL_8=
GRAY_HIGHLIGHT=0
GRAY_SHADOW=0
GRAY_GAMMA=1.5
GRAY_CURVE=/Users/windeking/Desktop/Curves/Chartthrobnegtest.acv
COPY_CURVE_C=K
COPY_CURVE_M=K
COPY_CURVE_Y=K
COPY_CURVE_LC=K
COPY_CURVE_LM=K
COPY_CURVE_LK=K
COPY_CURVE-LLK=K
And printed this step wedge:
<21step_gamma2.2.jpg>
I expected to get this result:
But this is what printed:
As you can see the 0% or 255 value printed white instead of black. The gradient at the top of the wedge showed the darks printing till the very end where it printed white again.
I opened the step wedge in photoshop and applied a levels layer which changed the output value from 255 to 254:
I printed this image and got the expected result.
I'm also curious about the choppy look on the right hand side of the gradient.
Thanks for all your help,
Alan
2014-03-10 by Roy Harrington
Hi Alan,
That's a known behavior. It was mainly introduced for people putting gloss-optimizer onto photo paper prints.
The way the whole OS printing system works there is nothing distinguishing pure white of an image from
pure white border around any image. So the idea was to eliminate all ink for pure white -- you could put GO
for everything from 0 to 254 and then cut-off the GO at 255. Basically you get control of where you want GO
by giving up the one gray value. So the QTR profile maker clears the pure white value of the ink.
Ordinarily this has no effect in other situations but you've found one here. You can take advantage of it
to control how much black border you want around your negative -- not having to alway cover the whole sheet
with black.
I don't know what you mean by the "choppy look on the right hand side of the gradient". It may be
just the scan but I can't see anything particular or strange.
Roy
Show quoted textHide quoted text
On Mon, Mar 10, 2014 at 8:07 AM, Alan Vlach
<alanvlach@...> wrote:
Roy,
...
As you can see the 0% or 255 value printed white instead of black. The gradient at the top of the wedge showed the darks printing till the very end where it printed white again.
I opened the step wedge in photoshop and applied a levels layer which changed the output value from 255 to 254:
...
I printed this image and got the expected result.
I9;m also curious about the choppy look on the right hand side of the gradient.
Thanks for all your help,
Alan
--
Roy Harrington
roy@...www.harrington.com
2014-03-10 by Alan Vlach
Thanks Roy,
That is something I guess will just have to be worked around - no value higher than 254 in an image.
As far as the gradient, there are vertical lines visible that seem to be separating the tones as opposed to a smooth transition.
Thanks
Alan
On Mar 10, 2014, at 2:13 PM, Roy Harrington wrote:
Hi Alan,
That's a known behavior. It was mainly introduced for people putting gloss-optimizer onto photo paper prints.
The way the whole OS printing system works there is nothing distinguishing pure white of an image from
pure white border around any image. So the idea was to eliminate all ink for pure white -- you could put GO
for everything from 0 to 254 and then cut-off the GO at 255. Basically you get control of where you want GO
by giving up the one gray value. So the QTR profile maker clears the pure white value of the ink.
Ordinarily this has no effect in other situations but you've found one here. You can take advantage of it
to control how much black border you want around your negative -- not having to alway cover the whole sheet
with black.
I don't know what you mean by the "choppy look on the right hand side of the gradient". It may be
just the scan but I can't see anything particular or strange.
Roy
2014-03-10 by Roy Harrington
If you are on a Mac you should look at Print-Tool. It's got the inversion for a negative
as a feature as well as the flip for emulsion-down. Also you really need to control the
color management which is problematic on the Mac with grayscale.
The steps you are seeing are the 8-bit steps -- 256 gray levels. In Photoshop the gradient
can be created "with" or "without" dither. "Without" shows the steps, "with" would not but
then the 21-step below would have fuzzy transitions.
Roy
Show quoted textHide quoted text
On Mon, Mar 10, 2014 at 11:24 AM, Alan Vlach
<alanvlach@...> wrote:
Thanks Roy,
That is something I guess will just have to be worked around - no value higher than 254 in an image.
As far as the gradient, there are vertical lines visible that seem to be separating the tones as opposed to a smooth transition.
Thanks
Alan
On Mar 10, 2014, at 2:13 PM, Roy Harrington wrote:
Hi Alan,
That's a known behavior. It was mainly introduced for people putting gloss-optimizer onto photo paper prints.
The way the whole OS printing system works there is nothing distinguishing pure white of an image from
pure white border around any image. So the idea was to eliminate all ink for pure white -- you could put GO
for everything from 0 to 254 and then cut-off the GO at 255. Basically you get control of where you want GO
by giving up the one gray value. So the QTR profile maker clears the pure white value of the ink.
Ordinarily this has no effect in other situations but you've found one here. You can take advantage of it
to control how much black border you want around your negative -- not having to alway cover the whole sheet
with black.
I don't know what you mean by the "choppy look on the right hand side of the gradient". It may be
just the scan but I can't see anything particular or strange.
Roy
--
Roy Harrington
roy@harrington.comwww.harrington.com
2014-03-10 by Alan Vlach
Roy,
Thanks. I am using the print tool so I can print without color management. One problem with the inversion is that the entire print area gets inverted which prints all the areas outside the image black. That can sometimes be a good thing but is not controllable and uses a lot of ink. Also, I assume the profile works the same way whether printing a flipped or unflipped image. That is, the curve doesn't invert when selecting the negative option.
Back to the 255 issue. I assume this was incorporated for piezography and other third party inks since the epson inks don't require GO. Does this mean that the curve in a profile can't be used to alter the endpoints of the ink distribution? I mainly use QTR to make digital negatives. The fussiest part of creating a profile is determining the minimum amount of ink to put down to achieve paper white in the final print. That is a trial and error process. However, it is possible to analyze a step wedge and determine for example that maximum black occurs at the 97% step or that paper white occurs at the 2% step. I don't know if QTR will be able to use a curve to adjust for the black, but it will definitely not correct for the white given what you just described about using GO.
Alan
On Mar 10, 2014, at 2:51 PM, Roy Harrington wrote:
If you are on a Mac you should look at Print-Tool. It's got the inversion for a negative
as a feature as well as the flip for emulsion-down. Also you really need to control the
color management which is problematic on the Mac with grayscale.
The steps you are seeing are the 8-bit steps -- 256 gray levels. In Photoshop the gradient
can be created "with" or "without" dither. "Without" shows the steps, "with" would not but
then the 21-step below would have fuzzy transitions.
Roy
2014-03-10 by Alan Vlach
Roy,
I think I just answered my own question about regulating the black ink. I ran a test and based on the quad file, QTR does limit the black endpoint. If this works it will really simplify determining the minimum amount of ink to get a paper white. Print a 101 step wedge using a test profile, find the percentage point that prints black, create a dummy profile using a curve with that percentage as the black endpoint, and the quad curve view will tell you what ink limits to use. Can't wait to try this out tomorrow.
Thanks,
Alan
On Mar 10, 2014, at 2:51 PM, Roy Harrington wrote:
If you are on a Mac you should look at Print-Tool. ;It's got the inversion for a negative
as a feature as well as the flip for emulsion-down. Also you really need to control the
color management which is problematic on the Mac with grayscale.
The steps you are seeing are the 8-bit steps -- 256 gray levels. In Photoshop the gradient
can be created "with" or "without" dither. "Without" shows the steps, "with" would not but
then the 21-step below would have fuzzy transitions.
Roy
2014-03-10 by Alan Vlach
Almost forgot to ask. How about a GO version and a non GO version?
Alan
On Mar 10, 2014, at 2:13 PM, Roy Harrington wrote:
;
Hi Alan,
That's a known behavior. It was mainly introduced for people putting gloss-optimizer onto photo paper prints.
The way the whole OS printing system works there is nothing distinguishing pure white of an image from
pure white border around any image. So the idea was to eliminate all ink for pure white -- you could put GO
for everything from 0 to 254 and then cut-off the GO at 255. Basically you get control of where you want GO
by giving up the one gray value. So the QTR profile maker clears the pure white value of the ink.
Ordinarily this has no effect in other situations but you've found one here. You can take advantage of it
to control how much black border you want around your negative -- not having to alway cover the whole sheet
with black.
I don't know what you mean by the "choppy look on the right hand side of the gradient". It may be
just the scan but I can't see anything particular or strange.
Roy
2015-01-05 by ctb@...
Alan,
Did you manage to get this direct negative printing working? I always wanted this but never managed to get it right. From a 2003 (!) altphotolist.org post:
"
Because the curve controls the ink laydown of each individual ink (at least in
the 4 color printers) it could theoreticaly be possible to design a
curve that inverts the image when printing. Then you only have to
edit your image and selekt the appropriate output curve (like:
negative for gum) in the print dialog. "
April 2003 Alt-Photo-Process-L: New Agfa transparancy film for inkjetWhen putting an extra curve on top of the image that cuts down 255 to 254 and 0 to 1 (to be shure) I still am missing the inverted 0% field that should print 100% in a 101 field chart.
Kees
2015-01-05 by Alan Vlach
Yes I did.
I didn't use a curve. I used the levels layer and set the output to 254. It seems like what you did should also work though.
Alan
On Jan 5, 2015, at 9:52 AM,
ctb@... [QuadtoneRIP] wrote:
Alan,
Did you manage to get this direct negative printing working? I always wanted this but never managed to get it right. From a 2003 (!) altphotolist.org post:
"Because the curve controls the ink laydown of each individual ink (at least in
the 4 color printers) it could theoreticaly be possible to design a
curve that inverts the image when printing. Then you only have to
edit your image and selekt the appropriate output curve (like:
negative for gum) in the print dialog. "
April 2003 Alt-Photo-Process-L: New Agfa transparancy film for inkjet
When putting an extra curve on top of the image that cuts down 255 to 254 and 0 to 1 (to be shure) I still am missing the inverted 0% field that should print 100% in a 101 field chart.
Kees
2015-01-05 by ctb@...
Hi Alan,
I did some more testing this afternoon. For me cutting down the highlights from 255 to 254 did not work. But when setting the curve display mode to 'pigment inks' instead of 'light' with a 1% cut down it works ok. Translated in photoshop values this is a cut down from 255 to 252.
When I try to insert this 1% correctio into the curve applied to the QTR profile it does not work. Have to look into that some more tomorrow.
best,
Kees
2015-01-05 by Alan Vlach
Kees,
The correction doesn't go into the QTR profile curve. It is applied directly to the positive image in Photoshop before printing. Any value of 255 in the positive image will print as clear in the reversed QTR profile because that value is reserved for gloss optimizer and will always be clear in the transparency.
Don't know why 254 didn't work for you. It does for me. The use of 255 for the gloss optimizer was relayed to me by Roy Harrington.
Alan
Hi Alan,
I did some more testing this afternoon. For me cutting down the highlights from 255 to 254 did not work. But when setting the curve display mode to 'pigment inks' instead of 'light' with a 1% cut down it works ok. Translated in photoshop values this is a cut down from 255 to 252.
When I try to insert this 1% correctio into the curve applied to the QTR profile it does not work. Have to look into that some more tomorrow.
best,
Kees
2015-01-05 by ctb@...
Hi Alan,
It probably won't work in the QTR curve because this 255 gloss thing happens before the curve is applied. Roy, can you confirm this? Could it be possible to lift the gloss optimizer flag as an extra option in the curve description file?
I'll check again if I can get the 255 => 254 working. But the fun is spoiled a bit by needing an extra correction to the file itself. I like the magic of process specific negatives directly from the positive.
Kees
2015-01-06 by ctb@...
Checked the 255 => 254 correction to print with a negative curve and indeed it is working! Must have done something wrong yesterday.
-k