PiezoK6 need midtone adjust, problem?

1

I have printed 21 step scales to verify midtones. K6/QTR w/HDcurves/Han. PhotoRag 308 The midtones look/sample at about 59% White paper reads 2-4% and black areas read 86-88% (I haven’t put in the new HD blacks yet, so that should improve)

Photoshop is set at Grey2.2

I worked out that using a Levels adjustment layer with the midpoint set to 1.3 delivers spot-on prints, where the 50% tile reads 50% and exactly matches other graphic arts reference greyscale samples. The other tiles read exactly or very close to their expected percentages, but with the black and white a bit off as noted.

My workflow may be more subjective than recommended. I do not have a spectrometer to sample prints. I use a good scanner with no adjustments and test in Photoshop, plus visual/eyes to evaluate results.

Is it a problem that I need the Levels 1.3 adjustment? If so, where am am I going wrong in the workflow?

2

I think you should read the manual that comes with the community edition. This talks about linear workflow vs icc workflow. If you are printing with an ICC that it will match your monitor (the easy way) but like all ICCs it will also crunch the shadows. The “normal” way to print Piezography is to print Linear and soft-proof for linear in Photoshop using the Piezography Matte Neutral profile and turning on “Preserve RGB” to simulate the linear print.

best,
Walker

3

I am following the manual. The grey strip is one of the provided targets, PS set to Grey2.2, save to TIF, print with QT-RIP.

I tried printing the same greyscale strip with PS to my OEM color R2000 with an ICC and got a similar result–a Levels at 1.35 got a perfect 50% and very good readings of the steps. Other than tone, the color one visually matches the Piezo one extremely well.