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Digital BW, The Print

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Re: a and b values on Canson Platine

2015-03-19 by richard@...

Jon, thanks for linking to the ICC profiles for all the different ink sets. It is actually really helpful for having an understanding of what the profiles are supposed to print on a number of papers.

H, If you are on a Mac you can see the measurements that were used to create these icc profile by opening them in the ColorSync Utility (just double clicking the profile should do it)—I'm not sure if/how this is possible on a PC. After you open it you can scroll down and click on row #12 for "DATA" and you'll see the measurements used to create each of the icc profiles. You can then copy and paste that into a spreadsheet and graph the L*ab measurements, or convert L* to Density (if you paste them in a text file, save and drag it to the linearize data script it will do the density conversion for you..)

Here is a set of L*ab measurements from an unlinearized K6 QTR profile I made quickly this afternoon with the Cone Carbon inks on Canson Platine. I'm trying to get a blog post finished up with screen shots of the ink distribution and unlinearized curve as an example of how you can smooth these things can be out of the box if you set the cross over points correctly (and use enough overlap). I use protective spray instead of the gloss overprint due to the the way I have the printer set up as a P2 print/digital negative printer, but I was amazed at how much warmer the Carbon inks are on Platine compared to matte papers—I have a few sheets of Epson Exhibition, and Hahnemuhle Photorag Pearl I might be able to profile and compare over the weekend.

I dug up the measurements I did last year with the selenium inks on Platine. These are meant to give a ball park undersanding of how Platine handles the two ink sets. If I had more time I would have averaged more readings because there are some erratic values in the lower end of the scale. The second set of measurements (selenium) isn't as straight nor as dense as the first set (carbon). I'm making profiles differently now compared to how I did a year ago, and it seems to have a big impact on how smooth the unlinearized profile prints. Anyway, like I said, this isn't meant to be written in stone, but to give a rough estimation of how different platine is from the other papers Jon has ICC profiles for.. I have to say, I love love love the Cone Carbon ink set for matte papers, but on Platine it is way to warm, even for me... The selenium set on platine has an almost gold-toned albumen/plum hue that I like a lot too...

Cone Carbon on Canson Platine
Lab A B 98.11 0.03 0.89 91.83 0.84 3.29 86.04 1.53 5.24 80.47 2.23 6.97 75.08 2.83 8.23 70.18 3.3 9.21 65.16 3.83 10.23 60.87 4.16 10.85 56.07 4.59 11.78 51.71 4.92 12.41 46.97 5.2 12.91 42.25 5.49 13.32 37.57 5.7 13.48 32.68 5.81 13.53 27.32 5.69 12.84 22.66 5.52 12.24 18.19 5.25 11.26 14.27 4.63 9.07 10.38 3.79 6.44 7.27 2.6 3.27 3.62 -0.17 -0.62

Cone Selenium on Canson Platine
Lab A B 97.24 0.1 0.45 88.42 0.56 1.31 83.62 0.9 1.47 79.45 1.31 1.57 75.52 1.7 1.64 72.19 1.97 1.85 67.49 2.45 2.18 61.6 2.96 2.94 56.84 3.16 3.27 52.26 3.33 3.61 48.28 3.16 3.93 43.07 2.81 3.87 39.23 2.31 3.93 35.01 2.25 3.78 29.51 2.45 3.82 24.62 2.41 3.49 20.69 2.34 3.31 16.77 2.36 3.1 12.93 2.09 3.03 6.65 0.93 2.13


Richard Boutwell


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