I have been facing a recurrent issue with exposure inconsistency on my prints for sometime now.
I am using the Piezography Pro 11 inks system with K5 curves (all my curves have been linearized using the Piezography Pro Tool): I prepare my file on Lightroom, export it as TIFF, process it down to Grayscale with Photoshop and then load it onto Print Tool, applying split tone and Black ink choice through QTR, saving the settings before printing.
I then assess the result and I might apply a slight local correction to my file on lightroom before going through the very same process as above, printing with the very same presets (as saved previously).
I find that in a number of cases the general exposure of my new print will be off by up to 1/2 stop! I insist that I am not changing the Split Tone settings (which would likely affects exposure) or any other preset, apart from the local correction applied on Lightroom. I surely should be getting the very same overall exposure! I often find that it is not the case.
Dear Eitan. If this is PtPd printing, mostly I’ve found it is caused by humidity variability in the paper. These have to be controlled incredibly tightly.
The other variable: We use a P9000 with K5 Pro ink for our negs. We make sure to agitate the cartridges (700mL internal bag carts) so there is NO settled ink visible at the bottom of the cart. We do this every Monday or before the print-session if longer time has elapsed. Also I do a regularly head cleaning on all channels prior to the negative print session just to ensure all ink in the nozzles is fresh.
I am only printing prints (no negative, as yet).
I do appreciate the importance of keeping all the variables and parameters under tight control, as much as possible. I also realize the utmost importance of keeping the printer and heads clean. I also take into account that the ink cartridges must be steered regularly.
Yet I notice that my inconsistency problem can to occur during the very same printing session, in the span of 10-15mn between the prints. The printing paper is often from the very same sheet, which I cut into two halves for tests.
Could it not be that the problem is caused by the Print Tool / QTR software, maybe, or in the chain process of producing the printing file and transferring it onto the Print tool platform?
Lightroom can be finicky. In order for a print template to save properly you actually need to set the printer settings to “Default Settings” and then do your settings and then save the print template in LR. The only way for LR to over-ride the settings in the printer with its own saved settings is this way. If you did not do it this way and instead chose Last Used or some saved preset in the printer dialogue at the time you created the LR print template LR may choose an arbitrary setting when printing and can cause this error.
It took a bit of time for this info to surface in my mind, sorry.