Light absorbing paint

[ADG]

I remember a couple of years ago a new type of black paint was announced promising damatically

reduced reflections from any surface to which it was applied. I believe this was patented, by

a british company possibly.

Does anyone else remember this, and is it now commercially available?

[Richard Ide]

Hi

I don't think this is the same product but I have used Winsor & Newton jet black designers guache for a long time. You can order it from any art store which sells Winsor & Newton artists paints. It has the lowest reflectivity of any paint I have used. The only disadvantage is that it is water based.

Richard

[Eric Woodbury]

ADG

What are you trying to do? There are some patented black surfacing techniques that can make things really black. Some etch into metal surfaces to create light traps. Others are paints that grow hairs, but these are easily crushed if you should touch them. Sometimes a glossy black is better because then the radiation that is reflected goes in a known direction. Other times, matte black is blacker because the reflection is scattered.

From the hardware story, many people like fireplace or BBQ paint. I have found that for paints, the best one is Krylon UFB or ultra flat black. It is what some telescope people use. Other telescopers use a black velvet-like product called flocking available from Edmunds.

Good luck.

[tim atherton]

I think you are recalling something some scientists in the UK produced that basically gave no reflections and absorbed 99.99999999% of all the light (or something like that) "the blackest substance in the world".

I don't think it was a product yet though?

[tim atherton]

http://news.bbc.co.uk/2/hi/science/nature/2732487.stm

[paulr]

"Others are paints that grow hairs, ..."

thanks in advance for the bad dreams ;)

[ADG]

Thanks Tim

That's the stuff, anyone know it it is avalable (for blacking camera internals etc)?

[Ernest Purdum]

This is a fascinating subject. Thanks for bringing it up, ADG, and thanks to Tim Atherton for providing the link to the press release. The illustration (as well as Eric Woodbury's mention of paints that grow hairs) confirmed my belief that what ever it was would have a very elaborate surface. I'd love to see the actual material, pits within pits within pits, though I suppose you couldn't tell much about that without an (electron, I would guess) microscope. How do you suppose they got a picture of something that soaks up all the light?

In Sicily there is a flower that grows wild which has the most intense red I have ever seen. The petals are super fuzzy. I hadn't thought about it before seeing those flowers, but it seems that to have the blackest black, or the reddest red, you have to have a really elaborate surface structure.

I had some of the low reflectance black paper. It was interesting how much the tiniest bits of lint would show up on that surface.

The blackest black I am aware of is that produced by an acetylene flame. Some other flames will also work. Microscopists used to use it when they wanted a totally black background. Unfortunately, once mixed with a binder, it loses much of its blackness.

Maybe a very black surface could be achieved by first spraying on a binder, then dusting on a solid material. It would be tricky to do, though.

[Donald Qualls]

The flattest coating I know of that's easily obtained and applied is India ink on bare, textured wood (sanded with 80 grit is just about right). Just about tied for that is Krylon Ultra Flat Black spray paint; applied over a black oxide primer, in a single, even coat, this stuff is dark enough to compete with flocking for the inside of a telescope tube (which is where I've used it). Multiple coats do *not* get darker, however; instead, they tend to fill in the surface texture that makes the paint so dark.

Lamp black applied direct from the flame is blacker than either one, but is both tricky to apply and not very durable...

[Mark Sampson]

Oddly enough, and only slightly off-topic- night-flying combat aircraft in WW2 were painted glossy black, as it was harder to detect than flat black. My guess is that searchlights etc. made flat black appear gray, but glossy paint reflected the light away as specular highlights.