If I touch a plastic surface for 1 second, how long will it leave a discernible thermographic signature?

Question

Any formulas for calculating the rate of heat loss; and any experience of observing thermographic images in a like case welcome.

Assume that in index finger at body temperature is used.

Answer 1

It's not possible to be precise - there are too many variables. A friend of mine's worked with military thermal imaging systems which can detect a hand print on a metal plate over an hour after a 1 second contact. You could probably do better under lab conditions.

Answer 2

approximately 9 hours and 43 minutes.