Infra red 'guns' - proper use

[JohnD]

On checking with an infra red 'gun', It's often said that the nature of the surface you are measuring matters.     A white or shiny surface will appear cooler than a matt black one.   This is thoroughly predictable on physics terms, as the white/shiny surface radiates less infrared, but it's good to see it in practice!

Oliver Snowball is an agricultural engineer in North Yorkshire, who posts videos about his work on YouTube.  He showed perfectly in a recent edition how an IR gun gives  lower temp from a shiny surface on the same object.   See here, about 12 mins in:   

https://www.youtube.com/watch?v=kBc3Ai_IliI

John

Edited February 26 by JohnD

[egret]

I tend to use them for temperature comparison, rather than absolute temperatures.  If you're looking at below about 100°C then using some black insulation tape to get a matt black finish is a good tip. 

[Escadrille Ecosse]

Nice video. Big welding.

As @egret says for comparing objects with a different albedo a bit of matt black tape is ideal.

There is a similar effect with matt and gloss paint on the moisture meters surveyors use for detecting damp.