Indigo

An unrecorded compact disc under a fluorescent strip-light in the kitchen area at my work.

I learned a bit about colour today... not sure I'm any the wiser though! As I mentioned yesterday, Wikipedia has the following to say about indigo:

Indigo is the color on the electromagnetic spectrum between about 420 and 450 nm in wavelength, placing it between blue and violet. Although traditionally considered one of seven divisions of the optical spectrum, modern color scientists do not usually recognize indigo as a separate division and generally classify wavelengths shorter than about 450 nm as violet.

Indigo and violet are different from purple, which cannot be seen on the electromagnetic spectrum but can be achieved by mixing mostly blue and part red light.

One can see spectral indigo by looking at the reflection of a fluorescent tube on a non-recorded compact disc. This occurs because the CD functions as a diffraction grating, and a fluorescent lamp generally has a peak at 435.833 nm (from mercury), as is visible on the fluorescent lamp spectrum.

Now... the trouble is that what you see in this picture will be partly determined by how my camera responed to the available light, and partly by how your monitor displays the picture.

In real life, as far as I recall, there was a definite darker band between the blue and the violet - that is indigo (at least as far as I'm concerned). But I can't actually see it on my computer monitor :-(

Which is a shame, because I'm quite probably blipping a shot about the colour indigo in which you can't actually see the colour indigo :-( On that basis, I'm with the "modern color scientists".

For an alternative view, see here, which uses the hex code #4B0082 to create an indigo coloured Web page.

Oh well... hopefully this was vaguely interesting. Violet tomorrow! Onwards and upwards...

[Previous indigo blip: none]