Basic theory
Spectrum in order of increasing frequency:
radio, microwaves, infrared, visible, ultraviolet, xray, gamma
xray and gamma do overlap but gamma has the distinction of having to come from radioactive decay.
I do not know how far you need to take the physics but light can behave as both a wave and particle. Particles are called photons and it is considered that two will never strike the same place, that is to say whatever energy the photon has is the only energy a section is going to get.
The equation for energy of a photon is E =hf where h = Planck's constant and f is the frequency of light. More here:
http://hyperphysics.phy-astr.gsu.edu/HBASE/mod2.html#c3
It is therefore quite easy to get things to ignore radio through infrared by choosing the right chemicals (the word you are looking for is work function if you want to release an electron or at least promote it to a higher energy level, go back to the top of the page on the link above).
Some stuff:
photographic film, even radiation detection when using photographic film uses a so called phosphor (turns radiation into visible light).
light dependent resistor aka LDR. Almost the reverse of an LED, they work by having light promote an electron (LEDs work by having a voltage promote an electron and then drop back to produce light). The material used affects energy required and as such is very well understood.
