Re: Flat black paint

Out here in Africa, I've found the flattest black paint available is called
"blackboard paint", used to paint blackboards for schools. Much less
reflective than any other paint I've used. As with most flat paints, you
need to use the lumpy part at the bottom of the can (without stirring) that
is mostly pigment with no oil.

Mike

----- Original Message -----
From: Brian Reynolds <reynolds@panix.com>
To: <pinhole-discussion@pinhole.com>
Sent: Wednesday, August 23, 2000 3:30 PM
Subject: Re: [pinhole-discussion] Flat black paint

> Brahma wrote:
> > Hello fellow pinhole camera engineers, which paint or spray-paint is the
> > best and most matt for painting the inside of a camera?
> >
>
> Krylon Ultra Flat Black is used by many ATMs (Amateur Telescope
> Makers). It isn't really great, but it's about the best easily
> available (in the USA) commercial flat black paint. In general
> painting a surface flat black isn't the best method, but it is easy to
> do.
>
> When checking a surface for "flatness" be sure to look at a glancing
> (shallow) angle to the surface with a bright light source also at a
> glancing angle. From face on most flat black surfaces look to be
> non-reflective, but from an angle they reflect a lot of light.
>
> There was a survey of different surface treatments used to prevent
> reflections published in an astronomy magazine. Flat black paint was
> worst. Black flocking paper was better. Black velvet (with the knap
> in the correct direction) was next up (although expensive). The best
> surface treament was something mixed with flat black paint to break up
> the smoothness of the surface. Crushed walnut shells (also used for
> non-slip floor surfaces) mixed in with the paint worked very well.
> Sawdust was OK, but it depended on how you got the sawdust. Some
> methods of generating sawdust (table saws I think) wound up polishing
> the wood, thereby increasing the reflectivity. Unfortunately the best
> treatment wound up being the hardest to apply.
>
> --
> Brian Reynolds | "Dee Dee! Don't touch that button!"
> reynolds@panix.com | "Oooh!"
> http://www.panix.com/~reynolds | -- Dexter and Dee Dee
> NAR# 54438 | "Dexter's Laboratory"
>
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Received on Wed Aug 23 15:05:40 2000