Carbon printing

Started May 31, 2012 | Discussions thread
OP Danny Contributing Member • Posts: 757
Re: Carbon printing

E Dinkla wrote:


That is more or less correct but you still want the lighter grey inks used in the highlights and the dark inks in the shadows etc. If you send a greyscale image in normal color mode to a 4 channel printer CMYK and the channels loaded with quad B&W inks then there will be CMY mixing of the different density grey inks from 0% to say 60% tone range after which the black also sets in. That means there will be dots of the Magenta 70% density etc also at the say 2% highlight that will be much more visible than the 15% yellow dots. With Photoshop ACV color curves or a profile based on that you can assure that the highlights are build by the 15% grey ink of the yellow channel, then the cyan channel gets in, then the magenta channel and then black in the darkest shadows. As I explained more briefly to you in the QTR mailing list. With the curves you also have less need for a strict similar density of the grey inks to the CMYK inks. On top of those color partitioning curves you can make a linearisation curve and embed them in a B&W ICC profile.

With your example of a CcMmYK printer the function of color curves becomes less important as the highlights will be build by cmY followed by CMY followed by black in normal color mode printing. Color partitioning curves can still improve on that though by creating a range of Y> cm> CM> K ink use (simple explanation though, you will need some Y amount throughout the range anyway). Plus a linearisation curve added will improve any imperfections in curves and ink density lay down.

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Met vriendelijke groet, Ernst

340+ paper white spectral plots:
update april 2012: Harman by Hahnemühle, Innova IFA45 and more

Ernst, thank you for your time and explanation.

The approach suggest does indeed not 'tell' the printer to use the lighter grey inks in the highlights and the dark inks in the shadows etc. Now, this is what I was afraid of from the beginning, because this way of working does not completely benefit from the 6 (or more) shades of grey. Right? And this leaves me with the whole ACV and linearisation story. This is all a grey area for me as I never had to work like this before. The MIS Paul Roark ACV curves download page does not work btw, a whole list of curves but they cannot be downloaded..

The other option would to drop the Carbon road and go for K3 inks with QTR. I like the idea to work with split tone as well, make color gradations in the shadows/mids and highlights, so take the process a step forwards.

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