Kapton emissivity in thermal IR

Cool. I wouldn't have thought it's this much of a difference.

Do you guys hold it on each others heads these days, to see who might have the scary flu?

A question - is it that the Kapton emissivity is low for IR or that the Kapton reflectivity at IR is low?

That camaera would sure make a handy fault finding tool for boards.

The emissivity is high and the reflectivity is low. The sum of E + R always equals 1. You can judge E and R by waving your hand over some material and looking at its temp with an imager or an IR thermometer; if it has low emissivity = high reflectivity, you'll see the reflection of your warm hand change the apparent temperature of the stuff. Which is why IR temperature measurements can be so tricky: you can seriously burn your hand touching a piece of copper or brass that reads room temp on an IR: the IR is seeing the reflection of the room, not the temp of the metal.

It sure does, like when a power supply is caved in and you don't know why. I found a shorted cap like that recently. Too bad they're so expensive.

John

age

Is this true? Reflectivity I think I understand. There will be an angular dependence to the reflectivity. Emissivity I'm a bit vague about....ratio of energy radiated to black body radiator at same temperature.

George Herold

A picture is worth a thousand words ... well in this case,

Ed

I once used a smear of wet cigarette ashes to get an IR thermograph reading from aluminum.

Cheers! Rich

It's true assuming the surface is opaque. If there's transmittance it's a bit more complicated.

Cheers

Phil Hobbs