Can ink settling can cause the color/tone of an ink shade to change?

inks
piezography

#1

Is it possible that ink settling can cause the color/tone of a specific ink to change? I am using Piezography2 with a warm neutral / selenium split tone ink set and having unexpected results on matte papers (mostly Hahnemuhle Photo Rag and Canson Edition Etching).

I decided to check linearization before printing & targets for custom curves, and found the results viewed in the linearization checker excel file have a reverse S-curve. Then after printing the QTR calibration target patches and viewing under my GTI 5000K lightbox, I perceive shade 2 to be cooler than the other warm neutral shades. I did remove and agitate the carts 2 weeks ago and did a power cleaning to remove a bad clog.

I suppose its possible that the ink slots are out of order but I was extremely careful when filling the cartridges. And the print results with glossy inks line up with the output from our other printer running the same ink combo. Would another round of agitation + power cleaningspotentially changethe hue of shade 2 ink to be warmer?

BTW These are the density measurements on Epson Enhanced Matte (measured at the 60% patch):

Shade 1 - MK: 1.6
Shade 2 - Cyan: 1.0
Shade 3 - Lt Cyan: .95
Shade 4 - Magenta: .75
Shade 5 - Lt Magenta: .49
Shade 6 - Light Black: .28


#2

I may have answered my own question after performing a power clean. The patches in shade 2 are now printing slightly darker and appear more similar in hue to the other shades of warm neutral.


#3

Hi Candela~

From your order history, I see you purchased a set of 7800/9800 refill carts and started using Piezography WN/SEL inks in Dec 2011- is this the system you’re asking about?
About how often have you been using the printer vs. how long does it sit unused?
Yes, settled pigment can effect both the density and “color” of inks. Regular agitation of carts, and use of the printer will help keep the pigment in suspension, for accurate and full density output. If dealing with settled pigment, the best thing to do is agitate all the ink carts, then do 2-3 power clean cycles to purge settled ink from the ink lines, and get full density ink from carts to the print head.

Here are my measurements on Enhanced Matte paper at 60%:
Shade 1= 1.51- 1.55
Shade 2= 1.11- 1.2
Shade 3= .91- .95
Shade 4= .69- .74
Shade 5= .33 - .35
Shade 6= .21- .23

Are your prints now back to normal?
Best regards~ Dana :slight_smile:


#4

Actually this ink was purchased and installed in late Nov./early Dec. 2013. Before installation the 7800 was flushed with Piezoflush. It normally is used at least once a week but there was a couple weeks in late Feb./March that it didn’t get used.

I have removed carts & agitated, then did 2 power cleans, & the hue of the inks looks normal now. I will try a test print again and see what happens.
The 60% measurements on Enh. Matte (after agitation, 2 power cleans, 48 hours dry down) are:

Shade 1= 1.61
Shade 2= 1.05
Shade 3= .94
Shade 4= .76
Shade 5= .45
Shade 6= .29

Thanks for your help!


#5

Your share 2 still seems light to me, but please let me know how your test print looks!


#6

My test prints on glossy are now looking normal. The ones on matte are looking better too.

While sorting this out, I was making BW prints on my Canon ipf9400 (files in Adobe RGB and using custom profile for the Canon). The same files printed on the Canon with this workflow printed with more contrast (in the mids and lower tones) than they had on the Pieozography machine. The Canon prints were not as linear and “open” as they were printing with Piezography matte. I measured the dmax of the Canon prints and they are about 1.6 on Photo Rag, so its similar to Piezography dmax on this paper.

Thanks for all your help and I’ll be sending in profiling targets for custom curves soon.


#7

Excellent, I’m glad to hear your test prints are back to normal now.

I’ll keep my eye out for your targets, and email you the curves as soon as they’re ready.

Best regards and happy printing~ Dana :slight_smile: