Piezography Ink Shelf Life

[John Bowen]

I see where it is recommended Piezography inks be used within two years. Jon Cone has stated that he has folks using inks that are up to 5 years old, but they don't recommend it. Apparently keeping the inks from evaporating is the key to using 5 year old inks. So my question(s): What exactly happens to inks once they reach their expiration date? Do they somehow change?

I'm thinking of purchasing larger bottles next time, but don't realistically expect to consume them within two years of opening them. Seems to my simple mind we could decant them to smaller bottles as we consume them to reduce evaporation. And someone on this forum must know what substance it is that is evaporating (i.e. distilled water, some form of alcohol, etc) so that if my 110ml bottle evaporated down to 90ml, I could just add 20ml of ???? to bring it back to spec.

Inquiring minds want to know,
John

[Tyler Boley]

I never thought evaporation was the issue, how will that happen in well sealed containers like the nalgene bottles? My concern, and I assumed that of others, was the various elements potentially separating- most obvious the pigments falling out of suspension. I have bottles I go through and rarely check the dates, and I know some are around 5 years. But whenever I go to the self to use some ink, every few weeks or so, I agitate all the bottles. I've never noticed any density changes or any problems. If yours have sat though, I'd make sure and agitate them for once a day a few days before putting in a printer, but I wouldn't let them sit stagnant for weeks or months anyway.

[John Bowen]

Thanks, Tyler