"Warren" wrote in news:nhXmc.48205$0H1.4560042
@attbi_s54:

Pen wrote:
I know what you mean. The ink on thermal paper will fade in the sun.
Home depot has a 1 year warranty on plants with a receipt. It's funny
that after 1 year, the receipt fades into a blank sheet!

There's no ink involved with thermal paper. The writing on the paper is
caused by heat. That's why it's called thermal.

Without getting pedantic about 'ink' here is an interesting summary of
thermal printing technology:

http://www.lintech.org/comp-per/16THERM.pdf

For what it's worth, they call the thermally sensitive material 'dye'
(16.3.1 Direct Printing on Thermal Paper, p.5).

If you keep the receipts out of direct light, in a cool, reasonably dry
place, they should last many years. Store them on the dashboard of a
car
in a humid climate, and they won't last a week. If they're lasting less
than a year, you're probably storing them closer to the later than the
former.

As for the original question about putting them in the compost bin, I
wouldn't. I wouldn't put wax paper, gift wrap, or any other product
that
is just paper-based, and not really paper.


The crystalized ones I mentioned have been stowed away in manila
envelopes or paper boxes, 60F-80F. Most of them are legible, but the
contrast is unusally considerably less. But I also have some that have
had the heat exposure (esp. pizza hut) and are ~50% dark.