I would like to point out errors when using a non-contact Infrared thermometer and it is called emissivity of an object.
Since the price of Infrared indicators have come down greatly over the last few years more people are buying and believe what the instrument temperature is indicating.
Most Infrared indicators come from the factory with the emissivity set at 0.95 (organic). Here is a table that lists the emissivity of several objects http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html
Here is a simple experiment to try. Take a shiny stainless steel kettle small enough that you can boil water on the stove. Bring the water to a boil. Everyone know that water boils at 212 degrees F at standard pressure at sea level. So the water is boiling and the non-contact Infrared indicator should read about 212 degrees F (possible less because of the water vapor) when pointed at the water which is organic (0.95 emissitity). Now read the side of the SS kettle. The kettle side should read close to the same temperature of the water in the kettle since both are in contact with each other but it does not, Stainless Steel, polished has emissitivy of 0.075 from the table link above. The side of the kettle will read almost half the water temperature.
This next experiment is where you need to be careful as to not burn yourself! Take your organic hand and place close to the side of the stainless steel kettle, not very hot but quickly touch the kettle side and you would feel HOT!
Now for the next experiment. Take a cast iron skillet (e of 0.65) and a stainless steel skillet (e of 0.075) and heat up on a constant heat source and place your hand close to the surface but do not touch the surface!! You can get burnt in an instant!! The cast iron appears hotter than the stainless steel surface.
Temperature also applies to full contact thermocouples since thermocouples are not linear in the temperature curve. Thermocouples can have a lot of error depending on the manufacture because of what is called the hot point and cold point reference temperature.
Now you know, don't believe everything that is indicated but filter the error though your mind!