Digital BW, The Print

The 7800 with Carbon-6, using the C6c base variation (Tergitol surfactant added to this latest version -- see http://www.paulroark.com/BW-Info/Ink-Mixing.pdf), sat idle for 3 1/2 weeks, and I am pleased to report there was no significant evidence of settling of the ink in the tubes.  Also, all the dilute ink nozzles were perfect prior to any cleaning cycle initiated by me.  The only defect was one Eboni MK nozzle that needed an overnight Windex soak to clear.  Before that soak, I printed with the single gap and noticed not visible banding.

My main concern with dilute Eboni carbon inksets has been the faster than normal settling of the relatively large Eboni particles.  (The larger particles -- still tiny relative to the nozzles -- are most likely why they're also relatively neutral.  It's a trade-off.)  With my old 7500 I could not tell if the settling was just in the carts or also in the tubes between the carts and head.  Due to the 7500's rubber gasket seals between the carts and printer, I was attempting to agitate the carts by rocking the printer.  That seal tended to leak after the carts had been removed and re-inserted too many times.  Rocking the printer was most likely ineffective in terms of agitation and the source of most of the settling.

With the 7800 I remove the carts and give them a good agitation.  My hope is that the modern seals/valves can handle this.  Time will tell.

I'll document my experiences with this 7800-C6 setup here:
http://www.paulroark.com/BW-Info/7800-Carbon-6.pdf 

So far, so good.

Paul
www.PaulRoark.com

(Re-post/correction) 

I've posted some print tone information for the 7800 - Carbon/Eboni-6
combination. See http://www.paulroark.com/BW-Info/C6-7800-tones.jpg The graph is of Lab B values for 21-step test strips. Lab B is the main variable, Lab A being set by the paper and not varying much within the print.

Note how similarly H. Photo Rag and Premier Art Generations Alise Natural print. HPR had a slightly higher Lab A, and PA Gen. Alise had a higher dmax.

(In the original post I noted cooler spectro readings for the Epson driver at 1440 v. 2880.  This difference, however, appears to have been from a difference of paper batches or some other source.  I could not duplicate the results on the same piece of paper and measured at the same time.)

Paul
www.PaulRoark.com