Best spray paint for IR (NIR) CCD Camera?

[Red-Rx7]

Hello,

I have been searching the internet without much luck. I was hoping someone here could provide some light (no-pun intended) on the question I have:

I would like the spray paint to show on an IR Camera image. What is the best Spray Paint color/type to use, for an optimal IR CCD (NIR) Camera picture?

Thanks!

[DonRotolo]

You need to think in terms of heat. What reflects heat the best? Black or very dark green, actually.

The property you seek is emissivity, specifically in the NIR band. Contact a paint manufacturer, ask for engineering or applications engineering and ask them what paint color/forumlation to use, they'll be happy to help. Krylon for example.

By the way, no color will show up better than another IF there is no temperature difference OR it is not being illuminated by IR light.

Don

[Red-Rx7]

Originally Posted by Don Rotolo

You need to think in terms of heat. What reflects heat the best? Black or very dark green, actually.

The property you seek is emissivity, specifically in the NIR band. Contact a paint manufacturer, ask for engineering or applications engineering and ask them what paint color/forumlation to use, they'll be happy to help. Krylon for example.

By the way, no color will show up better than another IF there is no temperature difference OR it is not being illuminated by IR light.

Don

Don,

Thank you for the response. This sounds very logical, in which I have placed a call into Krylon for an answer. Unfortunately, I have been transfered to 5 different departments, and now have a message with Sherman Williams Military Aerospace lead chemist; he was out to lunch when I left the message.

For FYI purposes, I will respond back with the answer they give in the event other people may want to know this for future archiving purposes.

Thanks,
Mike

[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

[Alan Anderson]

Originally Posted by 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.

It's not obvious to the eye, but many black paints are reflective in the infrared. They get their dark color because they absorb visible light, but the mix of pigments isn't chosen for anything outside that range of wavelengths. True "blackbody" black is very hard to come by.

Similarly, many white paints are actually pretty good at absorbing IR.

I once saw a mention of an IR-reflective paint in an article about home theaters. It was gold-colored.

[Elgin Clock]

Are you restricted to a painted surface? Can you use a vinyl material?

I'm sure some folks who responded before me already can shed some info on the subject, but in our world of robotics on this forum, our camera we used which tracked color had a lot better success with a lighted surface than a vinyl surface than a painted one.

The camera tracks light awesome (most of the time). - Best medium so far.

Vinyl (which was reflective enough) semi-decent.
(My team personally had good luck with this the first year that medium was introduced as a tracking material)

Paint (on cardboard, or wood) was horrible to track.

I don't know if the camera you are referring to tracks the same as ours, so hopefully the engineers/mentors/teachers who responded before me can relate this somehow.