Solved: changes in linearization


#1

Dana

I tried a piezo print on the moab entrada bright white you had made a custom profile for late last year. I saw some issues in the print so printed the 21 step chart and measured it again and compared it to the original measurement I did after getting the curve. There is a difference in the lin chart that matches what my eye saw - a sudden bump at around 90 that results in a “cliff” as the tonal range moves toward darkest shadows.

I’m not sure what could cause such a difference in the chart (and the prints) from before, nor what I can do about it at this point. In your experience what may be going on and what, if anything, can I or should I do? At this point, this paper isn’t really usable for me now.

I haven’t been doing much printing (waiting for the GO issue to be resolved) but have been agitating the carts, doing nozzle checks, etc. regularly.

If you would like to see the original lin chart and the new one, I can email them to me. I was not able to upload the excel files via your uploader built into this support application.

Addendum - I just did the same “retest” of the Optica One custom curve you made at the same time. It also has the same bump at 90 - it additionally has some noticeable “lifting” between 20 and 65 (the Moab was fine except at 90). This target I measured after printing and using a hair dryer for a minute as opposed to letting it sit overnight. Not sure if that might contribute to the additional changes in the lin curve or not, but the bump at 90 is the same for both papers. The bump starts at 85, peaks at 90 and is back to normal at 95, so it’s very constrained. Unfortunately an aberration at this point of the curve is very noticeable in prints. So at the moment I don’t have any papers I can reliably print on!

Thanks
Bob


#2

Hi Bob~

If you haven’t been printing much lately, you may be dealing with settled pigment (nozzle checks don’t do much to keep ink moving thru the lines to prevent settled pigment). The key is to regularly shake the ink carts, AND use the pinter by making at least one letter size print or a few cleaning cycles every week to avoid ink from sitting still in the lines for too long, which will cause density shift in your output. If you are dealing with settled pigment in the ink lines, just shake the ink carts, and do a few Power Clean Cycles to get full/correct density ink flowing thru the lines. Make a small test print including the standard 21 step strip to dry + measure, to check against the “before” print.

Please let me know if you have questions or how your output looks after my suggestion.
Best egads~ Dana :slight_smile:


#3