The science of colour.

[Hippogriff]

If I had a bunch of LEDs that are in a mount, and I want to ensure maximum brightness and reflectivity, what would be the best colour of surround to use? At first I thought a mirror-like material would be the best, obviously that reflects all kinds of light well. I can see silver and white reflective vinyl sheets and rolls of tape on eBay that I'd be willing to take a punt on... but thought it worth asking this question.

If my LEDs can be any colour, what 'colour' reflective material would be best to ensure maximum reflectivity - mirror, silver or white?

 

[carbonzit]

Any of the above, since they're all color-neutral. Of course, there are lots of whites, some of which aren't at all pure white.

 

[crutschow]

The difference between the three is the directivity of the reflection. Mirrored and silver surfaces tend to reflect more in one direction than another so the light will seem brighter from those directions. A matte white surface appears equally bright in all directions (Lambertian). So the material you use rather depends upon how wide an angle you want the LEDs to be seen.

 

[Hippogriff]

I've took the plunge and ordered some mirror cards and some white reflective vinyl... will be interesting to see if there are any noticeable differences at all.

 

[Sceadwian]

Strictly speaking you should get better results with the mirror as it won't absorb as much of the light as the white material will, however it depends on how the mirrors are arranged and the direction of the LEDs. One setup may provide more light at the center while the other might provide more overall light but spread out over a larger area so it will read as dimmer even though the overall output is higher so how you measure the brightness is important, and that depends on what you're intending to do.

Just a side note, most LEDs are not very good broad spectrum light sources, they might look white to us but if you've ever seen the spectral output of one it's VERY peaky, and the color rendering index (spectral flatness) is only about 75 for a common white LED, you can get higher, probably in the 80s if you buy more expensive LEDs designed with better phosphor blends, but if you need a true broad spectrum light source halogens are much better. Don't know if that's important to you but the title of the thread is the science of color.