UT-3D / 2200 curves help
2009-05-18 by esharamaki
I had a nice block of time this weekend to sit down and get more familiar with adjusting curves. I'm working with an Epson 2200 and the UT-3D inkset with PKN in the black position (instead of Eboni), printing on Kirkland glossy paper and using print fix pro colorimeter to take measurements. I'm also using the QTR create icc -rgb app with the RAW photoshop file to create the profiles. I started by printing a couple step wedges, (1) without any curve (2) with "start matte.acv" curve and (3) with "start glossy.acv" curve. The matte curve was the most neutral so I worked with that curve. Basically, I made offsetting adjustments of the red and green curves leaving the blue curve alone. I was shooting for slightly cool print trying to maintain lab B around -1. When the curve is applied, the step wedge on the monitor essentially has multiple shades of one color, (kind of maroonish/brown/red/magenta) so mostly cool ink of the M and LM ink positions. (Is this wrong?) Between the 25%-50% steps, I get this spike up in lab L (up from -1/0.5 to 2.5)and then rapid drop back down below 0 afterwards. I've made all sorts of adjustments to the red and green curves and I can't get this portion of the step wedge below 0. Can someone give me a hand and explain what is going on? What curves are affecting this and how? Thanks, Earl