Digital BW, The Print

Hello Paul,

> Are the platinum compounds in solution, or are they pigments in suspension?  If a pigment, can you get then ground small enough to stay in suspension reasonably well?  It sounds like an interesting project.
> 
it is the former case. I did not even considered pigments as I believe platinum is just too heavy to be kept in any suspension. Unfortunately, a couple of months ago I discovered that my Carbon-Gelatine workflow had a flaw and I had to spend quite some R&D to modify it, stopping the development on inkjet platinum prints. This had to do with the washing step of the paper after carbon printing (thanks for mentioning it in your write-ups). Apparently, some papers (like Magnani Pescia which is by far my favorite) change their structure once dried, assuming a stiffer behavior. I believe the internal sizing of the paper gets damaged by the washing procedure. This is fine in the very humid climate of Southern Italy, where the washed and dried paper appears almost unchanged. However, in October I visited a friend near Chicago where the ambient humidity was around 15%, and the few prints I brought with me to eventually show to local galleries became intolerably stiff and warped. 
The hard part of the new workflow, where the paper is not washed anymore, was to devise a new technique for gelatine coating a dry (rather than wet) sheet of paper. I almost finished such development (actually, the appearance of the prints with the new workflow is even better than before) and I am ready to restart the inkjet platinum project.
 

> 
> I mostly experimented with propylene glycols for the pigment base.  Low toxicity was a main issue there.  I found that as I increased the amount of the glycol, the printing became rougher.
> 
I did experimented with PE as well for the same reason (an because it is also substantially cheaper than Ethylene-Glycol). With carbon pigments it was a total disaster as the carbon precipitated from the base in matter of a couple of days. With dyes/platinum compounds, both glycols are equivalent.
 
> 
> > ... The reason for using HP thermal heads is that platinum compounds are too expensive to be used in the very wasty Epson printing systems, while HP is far more conservative in ink usage. 
> 
> Why is that?  Fewer cleaning cycles?

It is mostly for that (HP7450 makes essentially no cleaning cycles), but also because zero clogging and also a lower ink deployment during printing.

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> It's definitely true that MIS inks are cheaper.  On the other hand, artifact free glossy prints do, I think, have uses.  Part of my interest is simply to explore the alternatives.
> 
May be I am wrong, but with the harsh competition among Print on Demand companies, I think the cheapest and easy way for making brochure is with commercial companies. 
I understand your point regarding exploring alternatives. My impression, however, is that you carry such an extreme level of influence in this community that when you start new projects the crowd following it is correspondingly large, with obvious consequences. Just look at the number of posts in this thread. 

  Mantinieri

http://www.mantinieri.com