Guidelines for calibrating and printing to Gracol 7 www.gracol.com
We are going to have some press time to look at Gracol 7. Read through the how to last night and had some questions.
So will read through again and throw out the questions as I see them.
Calibrating a proofing system. The big difference in a proofing system is fixed SIDs, grey balance is achieved by separate rip curves.
So you would adjust the desired curves to get the a* 0.0 b* -2.0 values on a proofer??? Would you then profile the proofer, would this not affect the neutral grey when you reapply the profile. Or are they talking about not using profiles and just running to grey balance without the profiles???
Press Calibration Run
Print to nominal densities. I already know our Bengal Inks at the proper SID will not have the L.A.B. values needed. I am not sure what to do here. We are running the same inks the Gracol Press runs did??? I believe we should ignore the SID values and run to the LAB values???
They say use a non-polarized density. With Gracol 6 we used a XRite 500 series with a the polarizing filter. We find that with the filter measuring wet densities we produce a good image. If we tried to run to Gracol 6 wet densities on our XRite ATD with out a polarizing filter our dried back press sheets lack contrast. So I question these values. Unless they are giving some dry back time. Wet Black density will measure 1.70 through polarizing filter but measure 2.20 with out the filter. Gracol 6 S.I.D. values only worked for us with wet densities on press with the polarizing filter without only the dry values worked.
Forcing the device to Gracol 7 curves
Plot the curves Redraw the target above 50%, so do you just swing it down preserving the shape. Or why would you do this. Why not just build the curves to do this??? Why doesn’t this disqualify the whole test???
Step 5 0r step 8, This is just two ways to achieve the same thing
Second Press run should work to density - fine tuned to 50% cmy patch lab values