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Dear all:

I am a beginner and I have a question regarding the determination of the ink densities to be used under the 'Ink Setup' tab when using multiple gray inks.?

O.k., Paul Roark calls it a 'judgement call'. With my very limited experience I fully agree. But regardless of that I would like to better understand the procedure which I found in several documents. Accordingly, the ink density to be entered under 'Ink Setup' should be the result of the product of the fractions of the respective next darker ink which would yield the same density (or Lab L) as the ink at 100%.

I measured the Lab L values from a print of the calibration image for Hahnemühle Photo Rag 308, the GCVT ink set of Paul Roark, resolution 2880-super and 50% global ink limit. The results for each ink are shown as circles in the image below.? All data can be well represented by exponentially decaying functions (lines).

If I follow the above mentioned standard procedure, the fractions are indicated by the labelled plusses and the densities to be entered under 'Ink Setup' are represented by the K values below the full diamonds (they do not lie on the K-curve, because the ink curves are not linear). Am I correct that these densities, i.e. products of fractions, should be used? I am asking, because the products of the fractions, although they certainly carry relevant information, have no obvious meaning which would help to visually understand the resulting ink curves.

Hendrik

PS: From the curves in my ink separation plot, is the global ink limit I selected (50%) adequate? The lighter inks still have a significant slope at 100%.