We're digressing from the subject at hand, but it allows me some self-indulgent nostalgia.
As you are no doubt aware, even black paint made to coat the interior of optical instruments has the problem of a quite high glancing angle reflectance. My nanoporous aluminum film has a very low glancing angle reflectance. I seriously doubt anyone would cough up 6 million bucks to produce this material in quantity. Maybe someone could be convinced to provide the capital based on the possibility of making a superior hydrovoltaic film. Not bloody likely. As a boy I used to make and modify all sorts of strange and unusual microscopes and telescopes. I was bedeviled by the reflections from the interior of the tubes. My solution was simple. I would deposit carbon black inside the tubes. A flaming q-tip soaked in motor oil and attached to a stick could deposit enough soot to eliminate almost all of the reflections from the inside of the tubes. You can even do this to the inside of cardboard tube if you are careful. Since I knew no one would be taking these gadgets apart but me, I had no worries about the surface being disturbed. There now. More than you wanted to know. ------- Original Message ------- On Tuesday, May 30th, 2023 at 6:27 PM, Andrew Meulenberg <mules...@gmail.com> wrote: > I no longer have the instruments to measure the absorptance and > reflectance of materials; but, most optical instruments have black > paint on the inside walls. A new source of very black films or sheets > could be a useful addition because, over the years, the paint turns > grey.
