I've got ideas for a few avenues that might be good to explore, but don't have time to explore them all.

1. Dye in cleaning cartridges/ all cartridges
As long as it's an organic dye, I don't think there's any reason why we might not be able to add some color to our inkbase. It would be much easier to view nozzle checks, etc. and shouldn't affect anything else.

2. Clogging/ unclogging
We need to explore further the clogging problems. It could be that I was completely wrong when I wrote the user manual, and that acidified inkbase is not a problem. If not, then we should never put anything _but_ acidified inkbase in (including in our cleaning cartridges) to avoid precipitation, which may well be a source of clogs.
We really need to find a successful protocol for dealing with clogs. Even using genuine Epson inks, these printers clog occasionally.

3. Acetic acid
If acidic inkbase is causing problems, it's possible that using acetic acid instead of nitric will be gentler on the nozzles. It shouldn't affect the solubility of our precursors- but then Bi(NO3) should be soluble in our current inkbase, and it isn't.

4. Optimizing thickness
With the new printing protocol, we can experiment with thicknesses. What I'm looking for here is an optimum thickness for the internal standards. The idea is to make the strongest signal on each internal standard come at a line about 1/3 of the triangle up from the point. Once the optimum thicknesses are found, everyone will be instructed to use the same settings on each print so our standards are consistent from site to site.

5. Homemade Ink Formulation
The group at Caltech believes that the MIS inkbase we use is primarily ethylene glycol, but we really don't know. It would be nice to be able to make our own inkbase- we could probably make it cheaper, on-site, and avoid whatever buffer MIS adds to it. The simpler we can make our inkbase, the better. This is what I will be working on next.