why are some paints so luminous?

July 12, 2005 2:57 AM

Why do the paints used on DynoRod vans, for example, have such luminosity?

What colour space do they use? What causes the intensity? What is the range of other colours that have the same effect? If it is a significant range, why are these other colours apparently eschewed when this example is so distinctive?

Colour monkeys, assemble!

Apologies to those who could help but don't know the specific example to which I refer - I'd send you to the DynoRod website, but the RGB version of their orange is bland and slightly murky.

posted by NinjaPirate to media & arts (3 comments total)

Luminosity- With most paints, the luminosity is related to the opacity/translucency of the paint. Paints that are more translucent and have white or light base coats underneath appear very luminous. Light actually goes through the translucent outer coat, then reflects off the base coat, and comes back through the outer coat. But if it is too translucent, the paint starts to lose color saturation, and then requires more coats.

Intensity - This seems more relevant to the bright orange Dynorod van you mention and probably has more to do with the particular pigment used to make their paint color (maybe Cadmium, or some other mineral/chemical). With bright colors in particular, I would imagine the dyes/pigments make a big difference for the intensity of the color.
posted by p3t3 at 5:59 AM on July 12, 2005

I may be way off base here, as this is really just a guess. The way you get those bright fluorescent pigments in highlighters and post-it's is by using pigments that take light in the ultraviolet range and reflect it back in the visible light range. The effect of this is that you get the normal reflection of the visible light (that is hitting everything else in the room) and then you get an added brightness from the ultraviolet light that is now reflected in the visible spectrum. This gives an apparent luminosity that is brighter than the ambient visible light would allow/suggest.

Maybe they are doing something similar with the paint on the truck. So you are getting *more* light reflected back at you than you otherwise would and it makes it bright and luminous. Can't say for sure, as I have never seen one of these trucks
posted by qwip at 7:37 AM on July 12, 2005

what qwip said.
posted by andrew cooke at 7:41 AM on July 12, 2005