is there such a thing as thermal paper fixer?
@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 quality of the image "burn" also influences it, a very finely dithered picture faded quicker than a highly contrasted text print for example
@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
@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.
@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