is there such a thing as thermal paper fixer?
@zens not that i know of, anything of the sort about increasing the longevity of thermal prints boils down to "scan it"
@zens i imagine you can make it last longer if you can laminate it in something that blocks UV light, but it's still not going to be a stable print
@zens longevity also depends on the quality of the thermal paper, i've printed on very cheap receipt rolls and had it fade in months whereas using a high quality fax thermal roll lasted for over a year so far under the same conditions
@zens the question of "is it UV or is it oxygen" is an interesting one as people in retro communities swear up and down UV exposure is what yellows plastics and i've had a dreamcast yellow to smoker teeth tinge completely light-sealed in a closet
UV affects thermal paper and keeping it dark should in theory keep it longer, but you're still fighting against the chemical stability of the paper itself regardless
i'm not sure, for thermal paper, if oxygen plays a part
@mavica_again i had an NES for 10 years perfectly preserved- moved from Melbourne to Sydney, and *all* my electronics corroded yellowed and died. in darkened storage both places-
it’s much more humid in Sydney
@zens @mavica_again dunno if it's your case exactly but IIRC for PET plastics it's a reaction with oxygen (CH + O2 -> COOH) that is very slow in the absence of light or heat to get it over its activation energy.
See e.g. https://pubs.rsc.org/image/article/2015/EM/c5em00207a/c5em00207a-f2_hi-res.gif
The reason old 3d printer filament goes to shit.
@mavica_again is the method of fading UV exposure or oxygen exposure? cos i have had receipts fade whilst sitting in a completely darkened envelope and drawer