Lazy light and star stickers

Wall stickers

Sometimes the colors’ world can be a kind of cryptic. A lot of numbers, measurements, acronyms tightly bind with discoveries, conventions and physics.

Today we went to visit Steve again, to have a little explanation about how to use the spectrophotometer he lent us but as usually, that became an occasion for a little colors lesson. Of course he taught how to make the zero calibration (3 times toward an open space light) and the white calibration of the instrument and then he passed to explain the meaning of the display’s numbers. D56 refers to the daylight. While, for example, the letter “A” stands for an artificial source of light such as tungsten.

Furthermore: CIE 1931, 2° refers to an experiment the misure the vision angle of people looking to a coin they handle, so at an arm-distance. While the convention CIE 1946, 10° refers to the same experiment but with a bigger coin, so the vision angle is wider.

Then, some other acronyms: if do a measure SCI you’re including the specular light, if it’s SCE you want to exclude it (it’s particularly important for glossy surfaces).

He made also al lot of charts trying talking about amount of reflective lights vs the incident light and at [dunno how] we end talking about phosphorescent and fluorescent material. Basically is a question of time. Fascinating how color can be relating with every sort of aspects! Easily speaking, when the light arrive to an object, this object suddenly reflects just a specific wavelength’s range, that is the colour we can see; and the non-reflected amount of light is converted in other energy: heat. But. Not every surface reflect the wavelength immediately, some delay can occur and, moreover, the late reflection can have a wavelength that is different from the initial one.

So, it’s the lazy, latecomer light that makes the stars stickers on my room ceiling bright at night.