Does anyone have or know of a good description of these terms? Blackbody, Graybody, ETC. Or know of a place to find them?

Blackbody has an emissivity=1. (also absorptance=1). It emits a radiosity S=sigma*T^4 were T is in Kelvin and s is a constant.

Greybody has an emissivity less than one, but constant over all frequencies. S=e*sigma*T^4 where e is emissivity. A useful approximation to some realworld material over some frequency ranges.

a realbody has emissivity varying with frequency. This is the way most realworld materials behave.

There is a great overview of relevant theory for thermographers at www.mikroninfrared.com you have to do some poking around to find it. I'll post a more direct link if I can find it.

Hey, thanks Pete!

But please remember to use the "KISS" method here so that I can figure it out on my 4-function calculator.

Thanks again, I'll head for the URL you listed.

I went back and looked and realized that the document I was talking about was a section of our infrared user manual.;

The whole manual is here
http://www.mikroninfrared.com/manuals/7200VManual.pdf

Unfortunately, it is 10MB. You only need chapter 7, "Principles of Infrared Imaging". As far as I know there's no way to get chapter 7 by itself.

I couldn't find any other links that provided a ground-level overview. If you don't find what you want at that link, you might also check out the message boards at snellinfrared.com

Those message boards are very active and those guys might have some suggestions on reference materials.

Try some web glossaries
http://www.raytek-northamerica.com/tools/glossary/view....ool_id=11&cat_id=1.2
or
http://www.vibanalysis.co.uk/infrared/infrared%20glossary.html
The best one is probibly
http://www.thermosense.org/Glossary.html
Definitions will vary a little from place to place.