QTR-Quadtone RIP

While I am waiting for my shipment of MIS Eboni ink, I thought I would play with creating a curve.  I wanted to try getting the photo black ink to print on glossy paper.

I fillowed the instructions for this, and set the ink limit (60%) and then scanned the 21 step reference print out, and entered the linearization values.

I then printed out a reference grayscale photo.  I was viewing it at gray gamma 2.2 on a reasonably weel calibrated monitor.  I found that the darks on the pront were lighter than the darks on the monitor, and the gamma was a little too light (maybe due to the darks not being dark enough?)

So I just increased the darkness of the darkest shades and lowered the gamma from 1.0 to 0.9.  I then printed the picture again and I got a decent result.  Quite close to what I had intended.

I did have some rather strong metamerism visible on the 21 step printout.  It was pretty neutral up to 60, then it took on a warmer hue until 80 where it got neutral again, then went warm  at 95 and more neutral at 100.  A very interesting effect and also visible in the areas of gradual shade changes in my test photo.

I guess I will have to avoid using the photo black ink and only use the MIS Eboni for my B&W prints.

-Tony