[snalty]

False colour is pretty much standard for many imaging techniques including STM.

[s0rce]

Its not even really false color, its just a look up table applied to the data, which is some equi-tunneling current or height map, don't know exactly how this is done, bit out of my field.

[jacquesm]

The tip is pointing down, so an increase in current would indicate a decrease in 'Z' coordinate of the sample surface.