Opsin/ST6 - Thermal Target Disappears in the Rain

Out at the range at 0400 to evaluate the steel targets after a cool, rainy night. Ambient temp was about 60F, with a persistent light rain and high humidity. Interestingly, the unmodified steel targets are still quite visible against the wooden backstop of the range. However, moving one of the targets so that some trees and foliage are behind it causes it to largely disappear.

This suggests that one low-tech but labor-intensive solution would be to build a thermally active wooden backdrop behind every target. I'm not sure what causes this wood to be so warm. The range backstop is old, discarded heavy timber similar to telephone poles (and probably treated with something?). The target stands are treated 2x4s like you would use for a deck or other backyard construction. One possibility is that as the wood is decomposing and the heat is caused by bacteria doing their thing.

There are problems with this solution. One goal of the thermal target project should be to avoid inadvertently helping active/passive NV shooters. Having rectangular constructed wood backdrops for every target would make them pretty obvious to everyone. We might be able to get around this by using tree trunks or fallen logs in a more natural pattern.