Is there any way how to make faint text reappear on old printed receipts?

Question

I've tried heat, scanning and photocopying but none of them worked. I could have sworn I heard something, somewhere once about either vinegar or lemon juice, but I think that might have been about making disappearing ink. I need *reappearing* ink! This is for tax purposes and is very important. Thank you!

Answer 1

It depends on the exact ink and paper used.

For example, the receipts you get at a supermarket are normally printed on heat sensitive paper (called thermal paper). You can test if it is this paper by holding a match near one (but far enough away to avoid burning it). Sadly with this paper fading is fast and almost impossible outside a forensic lab to fix.

However sometimes by very careful warming near a fire you can darken the whole receipt. Occasionally the change in brightness helps identify features. But note you cannot no back so if you darken it too much, your beat.

If it's not this type but actual printed ink you could try staining the ink but it will be very tricky. This is because the reason it is faint because the ink has worn away (probably after rubbing or UV damage) so the majority isn't there. As such you might be trying to magnify trace amounts.

I would suggest merely getting a good light in a dark room and if that doesn't work maybe try different colour filters on the light. Or if you you can borrow a very good scanner (24bit depth or higher) you might be able to do some image processing (try edge detection for one).