Digital BW, The Print

Ernst,


> Based on earlier messages I understand that HP PK delivers better Dmax in a 1:1 dilution to glop than pure.


Similarly, LK will often produce a better dmax than PK.  BUT this comes at a cost.  I think in most of the desktop Epson printers that I've used, the increased wetness of the print leads to more trouble with "pizza wheel" marks on the paper.  The OEMs knew what they were doing in coming up with PKs that hit a good dmax with less water and a lower ink limit.


> With that in mind what would be the further dilutions of a PK, LK, LLK inkset? The fourth place is occupied by HP MK. The 6 picoliter droplet size asks for a set of diluted inks: LK and LLK. So far you advised 33% PK for LK and 33% of that LK for LLK. Is that starting from the HP PK or the 1:1 diluted PK?


I'm working from memory here, but I think I dropped the 1:1 dilution from newer HP PK mixes.  I think I had this in a old 2200 and found that the 1:1 was not totally clog free.  Others who tried it did not seem to have problems, but to avoid the possibility that that dilution was more prone is such issues, I pulled it from future mixes.

I usually use a 30% denser ink to 70% clear base dilution for my standard steps.  The "LK" types of inks I've measured over the years seem to have been between about 30% and maybe a hair over 33%.  There is little practical difference if you're mixing with a scales.  With syringe mixing the 33% is easier -- 1:2.  The easier mixing is the main reason to use 33% as opposed to 30%.  The OEM HP Gray is closer to 33% -- maybe even a bit denser.

 
> The 6 picoliter droplet is not a state of the art solution but I have some reasons to go that route first with thermal heads. For example checking the thermal head clear base in practice.


Be sure to use an appropriate base for dilution with the thermal head.  Those bases usually have an ingredient in them that is not in my generic bases or, I suspect, in glop.  I think it is a high boiling point surfactant that will allow the water to boil but still be there to do it's job, including keeping the heater in the head clean.  If you look at some thermal head base MSDSs you'll see the substance (starts with "p"?), Wikipedia or other internet information source has notes on it.

I have used my blends in a Canon for a short time, and the results were mixed.  It worked, but not well, and I did not long term testing because the results were not good enough.  Lower viscosity and a base that is more appropriate would be the first things I'd check into.

Good luck with the thermal printer.  It probably is a technology that needs to be explored more for user-blended inks.  I've stayed with Epson in part because that piezo head is amazingly tolerant of viscosity and other variations.

Paul