Custom_Grafx
New Member
From what I can see... I don't think I'm able to measure Lch values with my setup? Does this mean I can't linearize properly?
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Profiling Versaworks 4
- Thread starter Riku Salonen
- Start date
P Wagner
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As I mentioned in a previous post, you need the Measure Tool application from ProfileMaker 5.x to provide LCh values (there are others, but they cost money).
Custom_Grafx
New Member
Oops! Sorry I was in a rush and didn't read properly
Thanks so much, I went searching and got the measure component for free from the xrite site. Working ok.
I'm now in the spot measurement module (screenshot attached), and "referenced" black 100 from my VW generated Lin. Chart, and "sampled" black 85, giving me a delta E of 0.3.
From what I'm hearing above, I am to use this delta E measurement to determine where to limit my channel - is this correct, and if so, at what value? When it gets above 0.5 or 1.0 etc etc? Am I understanding the concept or totally off?
Thanks again guys.
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eye4clr
New Member
You're going down the right path there.
Use that for C, M, and K. For C and M measure the 100% patch as the reference, then measure down the ramp as you watch the Delta E for Chroma (the middle number). As it gets to 1.0 you've found your restriction. For K watch the first number for Lightness and play the same Delta E game.
For Y, adjust as you need to make a printed ramp with equal portions of CMY print a warm grey. You want it to come out on the brownish side of perfect grey. It doesn't have to be dead on, but the better you make it the easier a job you're making for the subsequent ICC profile to map colors. As a rough starting point, begin with Y equal to or a bit higher than C. Do not allow the CMY test to be green. If it is, lower the Y. If it's blue, raise the Y.
Also, change the Delta E type to the bottom choice in the pull down list. It's something like "Delta E 2000". This is the most current and accurate version of the Delta E math.
For most solvent printers you'll find the C ends up lowest with M and K the highest. Often you don't restrict M or K at all and C can get some relatively large reductions. Never mind what I say, trust the measurements.
Use that for C, M, and K. For C and M measure the 100% patch as the reference, then measure down the ramp as you watch the Delta E for Chroma (the middle number). As it gets to 1.0 you've found your restriction. For K watch the first number for Lightness and play the same Delta E game.
For Y, adjust as you need to make a printed ramp with equal portions of CMY print a warm grey. You want it to come out on the brownish side of perfect grey. It doesn't have to be dead on, but the better you make it the easier a job you're making for the subsequent ICC profile to map colors. As a rough starting point, begin with Y equal to or a bit higher than C. Do not allow the CMY test to be green. If it is, lower the Y. If it's blue, raise the Y.
Also, change the Delta E type to the bottom choice in the pull down list. It's something like "Delta E 2000". This is the most current and accurate version of the Delta E math.
For most solvent printers you'll find the C ends up lowest with M and K the highest. Often you don't restrict M or K at all and C can get some relatively large reductions. Never mind what I say, trust the measurements.
Custom_Grafx
New Member
Thanks eye4clr. That all made sense surprisingly and I gave it a shot.
Am I right in interpreting "as it gets to 1.0" as "stop as close as possible to 1.0? For example, if it's 0.8 @ 95% but 1.3 @ 90%, go for 0.8 @95% because it's closer to 1.0 than 1.3?
One more question... in Eye-One Match, I have 2 options for a setting labeled "ICC profile calculation". Version 2, or 4. It is defaulted to version 2. Should I be using 4? Or is this not something I need to be too concerned about?
Thank you!
Am I right in interpreting "as it gets to 1.0" as "stop as close as possible to 1.0? For example, if it's 0.8 @ 95% but 1.3 @ 90%, go for 0.8 @95% because it's closer to 1.0 than 1.3?
One more question... in Eye-One Match, I have 2 options for a setting labeled "ICC profile calculation". Version 2, or 4. It is defaulted to version 2. Should I be using 4? Or is this not something I need to be too concerned about?
Thank you!
eye4clr
New Member
Pretty much. You don't need to nail the 1.0. This Delta E number is a degree of perceivable difference. IOW, it's the average viewers threshold where they go from "I don't see any difference" to "I just now see the tiniest difference". So if you're less than 2 delta E, you're fine.
Maybe someone else can answer this with more knowledge, but it's my understanding the v4 really just tightened the spec down more than any real change to the way color is mapped. As far as I know you won't see any real difference between the two choices.
Happy profiling! Your world is about to get much simpler with you more in control of your system.
Custom_Grafx
New Member
Thanks once again!
(and this should be a sticky in the Roland or colour management section?)
(and this should be a sticky in the Roland or colour management section?)
eye4clr
New Member
Sometimes there are big ink restrictions available if you go a bit above 1.0 delta E. Keep in mind the difference between 0 and 1 is a VERY small amount. And the difference between 1.0 and 1.9 is imperceptible. So if you can cut 10+ more percent out and your delta only moves 0.8, go for it.
Also keep an eye on the grey balance as you're making these decisions. I print the CMY ramp right along with the individual ramps to help me balance the choice of how far to push the delta E.
Custom_Grafx
New Member
That's intriguing - I'm going to try reprofiling a profile today. By the way, previously you said to aim for a grey which is on the brown side. When printing a patch of equal CMY.
Would you be able to specify a PMS-C colour which is close to what you mean? Am I looking at something like PMS Warm Grey 10 C as a benchmark? Or something more like 404C?
Custom_Grafx
New Member
Thanks Castek. I had always left it at default (v2) so never had a problem I guess.
I might try it on v4 and see if it works or not and report back to let you know.
Cheers
I might try it on v4 and see if it works or not and report back to let you know.
Cheers
eye4clr
New Member
Warm grey Pantones are a reasonable goal. Don't spends loads of time making it perfect though. Just get it reasonably close then carry on.
Unless you want to potentially print things without the ICC converting it. This workflow gives the maximum gamut of the printer and demands that your CMY grey balance in the ink restriction and linearization be VERY good. Note that you can then only send CMYK files through this workflow since there is no longer a mechanism to convert the RGB files well. Personally I find this method to cause more harm than good since I'll forget to set things back up properly or need to accommodate a reorder later and forget I "broke the rules".
Unless you want to potentially print things without the ICC converting it. This workflow gives the maximum gamut of the printer and demands that your CMY grey balance in the ink restriction and linearization be VERY good. Note that you can then only send CMYK files through this workflow since there is no longer a mechanism to convert the RGB files well. Personally I find this method to cause more harm than good since I'll forget to set things back up properly or need to accommodate a reorder later and forget I "broke the rules".
Custom_Grafx
New Member
Thanks again. Ok, I think I'm out of questions for now. Time to get re-profiling.
Custom_Grafx
New Member
I am reporting to confirm that ICC v4 does not work with VW (v4.4.3).
RIP process hangs at 1%.
It is possible in versaworks to do a linearisation with unsupported spectrophotometr? I have Colormunki and VW doesn`t have support for it.
However I can print a calibration chart form VW, measure it from other soft, export the readings to file and then open this file in VW.
Here starts the tricky part.
VW needs text file with LabT readings (where T is density).
Example:
L a b T
88.739 -1.023 -3.275 0.14
85.124 -6.387 -8.775 0.23
81.926 -10.826 -13.486 0.31
79.361 -14.229 -17.237 0.38
I use Argyll CMS to take the readings but i get only Lab values.
How can I determine what is the density from Lab values?
I know it`s possible. You can get it if you use supported spectrophotometer directly from VW.
Any ideas?
PS. Sorry for my english if it`s bad. It`s my third language.
However I can print a calibration chart form VW, measure it from other soft, export the readings to file and then open this file in VW.
Here starts the tricky part.
VW needs text file with LabT readings (where T is density).
Example:
L a b T
88.739 -1.023 -3.275 0.14
85.124 -6.387 -8.775 0.23
81.926 -10.826 -13.486 0.31
79.361 -14.229 -17.237 0.38
I use Argyll CMS to take the readings but i get only Lab values.
How can I determine what is the density from Lab values?
I know it`s possible. You can get it if you use supported spectrophotometer directly from VW.
Any ideas?
PS. Sorry for my english if it`s bad. It`s my third language.
Custom_Grafx
New Member
Welcome to s101.
From what little I know, you cannot determine a density value just from the lab values.
You need a program which has the ability to read/measure lch.
As suggested above by Castek Resources, I found I could get this reading by installing the "measure tool" component of Profile Maker, which was free. I however am using the i1 extreme, so am not sure if your colormunki is licensed for free use of that component of Profile Maker.
Have a look on the xrite website to see if you can use any measuring tool for free with your colormunki.
From what little I know, you cannot determine a density value just from the lab values.
You need a program which has the ability to read/measure lch.
As suggested above by Castek Resources, I found I could get this reading by installing the "measure tool" component of Profile Maker, which was free. I however am using the i1 extreme, so am not sure if your colormunki is licensed for free use of that component of Profile Maker.
Have a look on the xrite website to see if you can use any measuring tool for free with your colormunki.
eye4clr
New Member
these guys may have something for you
http://www.babelcolor.com/
http://www.babelcolor.com/
eye4clr
New Member
In argyll CMS i can take measurmets in XYZ, Lab, LCh but I don`t know how to compute density (T) from that values.
I`ve already try this but ProfileMaker doesn`t have support for Colormunki and it`s useless for me. They probably don`t want to make cheap and good competition for i1.
I have some tought questions.
Currently I printing using custom made profiles for my media/ink combinations. My ink supplier made them for me one day. I think they`re pretty bad.
I`ve deltaE 3 to 8 when I print using them
I cannot print exacly the same colors that I read from sample using spectrophotometer even if the picked color is in the gamut that printer can reproduce on media that I have profiles for.
When they calibrating my printer (ink limits) they printed CMYK calibration chart, measure it, and compare results to FOGRA39 specification.
For example they set my Magenta ink limit to 70%
because M70% from calibration chart have smallest deltaE compared to 100% Magenta from FOGRA. (5,67 deltaE). They do the same for other inks. Is that correct way to set ink limits?
Good side of this approach is:
I have color gamut that is theoreticaly almost the same as reference FOGRA39.
Bad side is:
I cannot print exacly the same color that I pick from samples using spectrophotometer. (high deltaE).
Is this problem related to the way they calibrated my printer or to the color profiles itself?
Currently I printing using custom made profiles for my media/ink combinations. My ink supplier made them for me one day. I think they`re pretty bad.
I`ve deltaE 3 to 8 when I print using them
I cannot print exacly the same colors that I read from sample using spectrophotometer even if the picked color is in the gamut that printer can reproduce on media that I have profiles for.
When they calibrating my printer (ink limits) they printed CMYK calibration chart, measure it, and compare results to FOGRA39 specification.
For example they set my Magenta ink limit to 70%
because M70% from calibration chart have smallest deltaE compared to 100% Magenta from FOGRA. (5,67 deltaE). They do the same for other inks. Is that correct way to set ink limits?
Good side of this approach is:
I have color gamut that is theoreticaly almost the same as reference FOGRA39.
Bad side is:
I cannot print exacly the same color that I pick from samples using spectrophotometer. (high deltaE).
Is this problem related to the way they calibrated my printer or to the color profiles itself?