How to protect for life , plant based alternative prints ?

My course tutor said plant based processes have a very short life , how to protect them for years ?

This is probably about anthotypes; i.e. prints made by selectively bleaching out the natural colorants present in plants like beetroot, carrot, spinach etc.
Keep them in the dark, in sealed plastic envelopes. Even then they may last for a few years, max. The best way of preserving them is to photograph/scan them and then use the digital files for archiving, and/or make archival prints from the digital files.

koraks said:

This is probably about anthotypes; i.e. prints made by selectively bleaching out the natural colorants present in plants like beetroot, carrot, spinach etc.
Keep them in the dark, in sealed plastic envelopes. Even then they may last for a few years, max. The best way of preserving them is to photograph/scan them and then use the digital files for archiving, and/or make archival prints from the digital files.

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Agreed! Anthotypes are inherently unstable.

Anthotypes made with turmeric and sprayed with a basic solution (carbonate, bicarbonate and borax, most commonly) are probably the most stable. The different bases give subtly different shades in the final print. I have anthotypes made several years ago that are to my eye (no formal testing) unchanged from when they were made.

Anthotypes made with paprika are the least stable that I have made. The color is wonderful but they fade in the dark in months.

Hey, that's interesting what you said about the relative stability of turmeric - you must have noticed as well that it shifts in color rather dramatically in response to pH changes. As I recall it goes blood-red in an alkaline solution; quite striking!

Not too long ago I tried making some carbon transfer prints using turmeric and paprika as pigments. Both were a total failure. The turmeric stains so badly that you end up with all yellow. And the tinting strength is pretty poor. The paprika didn't really produce a print; the material just clumped and wouldn't form a stable dispersion at all. Sorry, this is a bit of a tangent from the original question.

koraks said:

Hey, that's interesting what you said about the relative stability of turmeric - you must have noticed as well that it shifts in color rather dramatically in response to pH changes. As I recall it goes blood-red in an alkaline solution; quite striking!

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Yes, the final color depends on the base used and possibly the paper as well. I can get anything from a very reddish brown to a pretty neutral brown. If only I could find my notes, I could be more specific!

The color after treatment with alkali is much more light fast than the yellow is before treatment.

Examples can be found here: https://porfolio.gorga.org/anthotype

koraks said:

Not too long ago I tried making some carbon transfer prints using turmeric and paprika as pigments. Both were a total failure. The turmeric stains so badly that you end up with all yellow. And the tinting strength is pretty poor. The paprika didn't really produce a print; the material just clumped and wouldn't form a stable dispersion at all. Sorry, this is a bit of a tangent from the original question.

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For anthotypes one extracts the color into an alcohol and allows the residual solids to settle out before coating the paper.