5/29/08 Edit: Please also see:
http://thepropden.aokforums.com/black-p ... t1059.html
Foreword
Kustom Kolors is a subsidiary of Valspar, a company whose paints was supposedly used in ESB and ROTJ (I've not been able to verify this, however.)
I've heard that "Black Pearl" (like a very dark gun metal, almost black but with very fine metallic particles) and "Galaxy Gray" (a medium gun metal) might have been the colors used back then. That was so many years ago. Today, Kustom Kolors offers both of these but bear in mind we do not know if the formulation has changed, if at all. There may be some differences. Also, I'm not sure where this information originated from.
Black Pearl is in an aerosol can. It turns out that Galaxy Gray (slightly similar to Tamiya's Gun Metal and Duplicolor's T-177 Gun Metal) comes in a small glass jar for airbrushing. I don't own an airbrush so testing that will have to come at a later time.
Bsaically, Black Pearl is a black paint with some pearlesence. It's debatable whether it's a dark gray or not. Metallic particles will add a whitish effect to paint. Metallic particles can range in fineness; the larger the particles the more "grainy" they become. So paints with coarse particles will look like they have a lot of glitter, whereas paints with very fine particles will reflect with a subtle sheen without need for a gloss clear coat.
Back in the days of the production of the original trilogy, in dark, low lighting situations, anything that helps Vader's many facets refract or reflect light differently will allow the distinctiveness of his features to show up in celluloid film. I personally do not believe Vader was meant to come across as a zebra of alternating colors. Rather, I believe he was to be all black, but the painted highlights on alternating facets was necessary for the film camera to pick up the distinctiveness of his facial features in low light conditions.
Some dogmatically tell you "gloss black, gloss black, gloss black" and yet when you see photos of their work, their "screen-accurate" stuff just doesn't quite look right. Sometimes it's flash photography which over brightens anything it photographs, especially when photographed up close.
The advantage of Black Pearl (without a gloss coating) is that it gives a subtle sheen to the black without it being glossy and too reflective like gloss black.
Indoor studio lighting is going to be very different than outdoor. If you are trooping, then how you Vader is photographed is also a whole different story. Cameras might train their aperture on the brightness of your surroundings, so if you are in bright sunlight, your Vader costume might appear as one big black dark smear and your features would be obscured.
For indoor situations, Black Pearl might be advantageous. It's not "in-your-face." Quite frankly, I like it.
So that you understand the scale of what you're looking at, the above is a plasic 8" sphere photographed from 2-3 feet away (I tink)
I primed it with Duplicolor sandable primer (black). I then shot it with Black Pearl. No wet-sanding afterwards, though if I had shot extra layers, I might have wetsanded it at 2,000 and the buffed it.
Observe the granularity of the paint, and it's not bad for something that came out of a can. It's granularity is fine and subtle, so if you had a dark gun metal (not anything bright like aluminum) you'd probably create a nice contrast on your Vader.
Just an option. Not claiming this is exactly what they used on the screen helmets, but an option that can be purchased at WalMart for a reasonable price (visit their toy/hobby section).