Best spray paint for IR (NIR) CCD Camera?

[dtengineering]

While flat black will have high emissivity and would be great for working in the far infra-red where you are monitoring the heat given off by an object, if you are using something like the "Night-Shot" mode on a Sony Handycam, you are actually more concerned about IR reflectivity. This is, of course, because you are emitting an IR light from IR LEDs in the camera and looking to see that light reflected back at you. The IR from these cameras (and remote controls, etc.) is, as you say, NIR or Near Infra-Red, meaning that it actually much closer to the wavelength of red light than the IR images viewed in passive infrared imaging.

Based on my experience, white seems to show up quite well. I would avoid going with anything mirrored or shiny (or even particularly glossy) as if you view the mirrored surface from anything other than perpendicular to a flat surface on the object the light will be reflected away from you, rather than towards you.

You may also have luck with a retroreflective paint. If you look at the highly reflective stripes on cyclist's safey clothing at night, you will note that they are very effective at reflecting light back towards the light source regardless of the angle of incidence. I'm not sure how this would work in the near IR, but suspect it might be effective as well. I haven't seen a can of retroreflective spray paint on the shelves for a while... but I did get one at a Rona (Canadian equivalent of Home Depot) once and had some fun with it.

So there you go... one recommendation for white, one for black. Each is correct depending on what and how you are observing it. Nothing like getting a straight answer, eh?

Jason