ArgyllCMS B&W targen

[Emulator]

Experimenting with the targen command, to see whether the balance between B&W and colour could be beneficially adjusted, I tried an extreme case to evaluate the results of a totally grey patch set:-

targen -v -d2 -G -e4 -B4 -g949 -f957 %pcn1%

in the CAP957 batch file.

This should give 957 B&W and grey patches:- 4 white, 4 black and 949 grey.



This is the resulting scan of the 29 x 33 patch .tiff file printout. Nine hundred and fifty five B&W and grey patches and one red and one blue patch! (Why the red and blue??)

I haven't yet worked out how to evaluate the results to determine if the spread of grey is even. It probably will involve reading the patches and examining the distribution of values, rather a tedious process!

I also wonder what the ink usage (colour/black) combination is in creating the grey patches on the Canon 9000 II?

 

[Emulator]

I tried to read the black, white and grey patch chart with the ColorMunki Photo as usual. But it produced "too many patches" error almost every time and could only be coaxed into the occasional successful column read.

Looking at the typical A4 colour patch chart it became immediately clear that ArgyllCMS never places light colour patches in the top and bottom rows (i.e. the start and stop points) on the A4 sheet. By restricting the chart to greyscale patches only, the software had been allowed to place near white patches in these two rows. This had the affect of disrupting the patch reading process.

I have now produced another CAP957 chart with targen -v -d2 -G -e8 -B8 -g319 -f957 %pcn1%, i.e. 8 white, 8 black, 319 grey and 622 colour patches and it is very noticeable that the top and bottom rows are made up of the darker colour patches.



Hopefully, when these have dried I will be able to read these columns and make a judgement as to the effectiveness of the increased proportion of greys.

 

[3dogs]

Experimenting with the targen command, to see whether the balance between B&W and colour could be beneficially adjusted, I tried an extreme case to evaluate the results of a totally grey patch set:-

targen -v -d2 -G -e4 -B4 -g949 -f957 %pcn1%

in the CAP957 batch file.

This should give 957 B&W and grey patches:- 4 white, 4 black and 949 grey.

View attachment 2091

This is the resulting scan of the 29 x 33 patch .tiff file printout. Nine hundred and fifty five B&W and grey patches and one red and one blue patch! (Why the red and blue??)

I haven't yet worked out how to evaluate the results to determine if the spread of grey is even. It probably will involve reading the patches and examining the distribution of values, rather a tedious process!

I also wonder what the ink usage (colour/black) combination is in creating the grey patches on the Canon 9000 II?

On my tablet this is showing a strong sepia cast, will switch to the calibated screen and repost

 

[3dogs]

Still has a sepia cast, assume your original is good, so it must be my end.

 

[Smile]

I tried to read the black, white and grey patch chart with the ColorMunki Photo as usual. But it produced "too many patches" error almost every time and could only be coaxed into the occasional successful column read.

What software did you use? The i1Profiler and Colorport are not reliable try Measuretool from PM5 suite, it can measure and save without license. If you have i1 it will work fine, however for ColorMunki I don't remember if it supports it.

The problem with big gray charts is that while they help to fix gray balance, the data can have errors by printing and reading too. These have to be fixed before you feed data into ICC generator, or the generator itself must know how to fix this.

It's better to use tools and methods that allow manual fixing as it is more reliable this way.

 

[Smile]

I was amazed that i1Profiler can't read more than about 6000 patches, my mega chart for testing contained a bit over 10000 patches !

I hope somebody can answer my question about Gamutvision
http://www.printerknowledge.com/threads/profile-assessment.8249/page-9#post-67737

 

[The Hat]

Still has a sepia cast, assume your original is good, so it must be my end.

Well @3dogs your right, that’s usually where Sepia comes from…

 

[3dogs]

Well @3dogs your right, that’s usually where Sepia comes from…

For once, I cant think of a thing to say

 

[Emulator]

Perhaps I should point out for those unfamiliar with ArgyllCMS and its procedures, the patch sheets in posts 1 & 2 are the starting point of the process and are printed with no colour management. These sheets are subsequently read by ColorMunki or i1Pro and processed using ArgyllCMS software to generate data from which profiles can be made. The colours visible merely show the 9000 II's interpretation of ArgyllCMS patches without colour correction.

My purpose in this thread is to eventually show the results of varying the colour to B&W patch numbers ratio in the targen sheet of patches. This will hopefully, improve the B&W linearity in the profiles generated with the modified targen parameters.

No significance should be placed on the colours of these patch sheets at this stage. It is possible to down load the images from the PrinterKnowledge website if required.

 

[3dogs]

Perhaps I should point out for those unfamiliar with ArgyllCMS and its procedures, the patch sheets in posts 1 & 2 are the starting point of the process and are printed with no colour management. These sheets are subsequently read by ColorMunki or i1Pro and processed using ArgyllCMS software to generate data from which profiles can be made. The colours visible merely show the 9000 II's interpretation of ArgyllCMS patches without colour correction.

My purpose in this thread is to eventually show the results of varying the colour to B&W patch numbers ratio in the targen sheet of patches. This will hopefully, improve the B&W linearity in the profiles generated with the modified targen parameters.

No significance should be placed on the colours of these patch sheets at this stage. It is possible to down load the images from the PrinterKnowledge website if required.

Phew! What a relief! Thought I had (more) problems!!!!