I'm a little late to the thread, but thought I might chime in anyway.
The technique I use now I learned here on the forum after much discussion. In particular it was suggested to me that I look down on a parking lot or street from some height, to gain a perspective on what we try to re-create on our tables. As I was working in a high-rise at that time, it was easy for me to do, and I found the results pretty compelling.
In the past I have painted vehicle glass light blue, or dark blue, or silver. But it was suggested here that I paint them black. And the "look down on reality" test verified that that the overwhelming majority of car and truck windows do indeed appear black. But...
Somehow blue is a repeated perspective that people come to. And silver. And somehow I just didn't like the way black looked. And wondered why.
See ... most vehicle glass looks black because the insides are in shadow. But ... we often get a reflection off of the glass. And when we ask what color the glass is, we ignore the reflection and try to look past it, and say black.
But the reflection is there. Almost always. And it is, most often, either blue (the sky is reflecting) or silver (clouds or the direct sun reflecting).
So what I now do, also suggested here in the forum, is paint the windows black. And then dab some metallic blue (or maybe sometimes silver) in the center of the pain.
Then after all else is done and dullcoted, I dab the windows with a quick glosscote.
It really does come out looking good at gametime. It looks like black glass with a reflection. And it helps give definition to the window framing, even if that framing has not been done as well as I might have wanted it to be.
Some examples:
The motorpool for my Romanian force. Quite a mixed bunch. Not the best pic for my purposes here. But look at the Opel trucks -- particularly the green ones. You get a sense of how they look reflective. If you look at the Renaults in the back row you get a sense of the definition it gives to the window frames.
Aircraft often have a LOT of separate panes of glass. This helps show off the technique to good effect. Here are some Brand-X Romanian JR-79r bombers. Note both the reflective appearance and the definition of the framework?
It may read like an involved process. But in fact, because of the improved result it gives to even a bit of sloppy/inconsistent framework, I find it takes me LESS, rather than MORE, work to implement this technique. I used to frequently re-do my windows because of slip-ups on the frames. Now the black outlining result of this technique kind of fools the eye, and I don't feel compelled to get near-perfection on the frames.
Just my $ .02 worth.
