I'm not sure if something like this actually exists, but I figured it's worth a shot. What I'm looking for is a transparent red vinyl or paint that shines relatively clear (light pink-ish is fine too) when backlit. I know I've seen tailights on some cars that exhibit this behavior, so who knows. Thanks in advance for any help!
Might be a one-way reflective tinting film of some kind. Otherwise I don't see how it would be possible.
I think what you may be seeing with the cars is "blue dot" tail lights? Where there is a small, blue colored, circle, right over where the light is. When just driving with the lights on, the tail light shows red, but when braking, the light appears sort of a purple'ish. Or are you thinking of something different? For some reason, I'm picturing this sort of thing, like what you're describing on "tuner" type cars, whereas blue-dots are more typical on "hot rods."
The two examples off the top of my head are the Porsche 968 and the BMW 8-series. The 8-series looks like it's reverse lights might alternate between red and clear layers of plastic to get the effect, but I'm not sure. The 968's entire taillight is red.
Sounds like some kind of polarising film, when a specific light is shone it goes through one way, and when the film changes direction it goes the other. Other then that, what Slug says is probably more accurate.
Okay, I haven't worked with vinyls much, or any kind of film for that matter, but if the backlight is strong enough, could I get the light transmitted through a red film to be a very light pink? I'm mainly trying to find a way that I can red-out my taillights, yet keep the reverse-lights distinguishable from the tail/brake lights.
It's that film with strips of colour in it. Light shines between teh gaps, that's all. It's the same stuff they put on buses and taxis... you know the stuff? WHere you have adverts plastered all over teh bus, even the windows, yet when inside, you can still see out? It's that stuff. Car accessory shops should sell it. No idea what it's called however,
Yeah, shortly after I posted that last reply, I discovered a bit of information that revealed the secret of the 968's tailight. It seems that it has a dual-layer lense. The inner lense has strips of red film on it, as you mentioned above. As for the outer, fully-red lense, apparently it's a neutral-density lense/plastic. However, the only information I can find on neutral density mainly applies to photography, so I'm not entirely sure the effect that it has...
Neutral-density lens/plastic means that the light transmitted through the filter/lens is attenuated by the same amount in all chrominance and the luminance channels so the colour does not change only the intensity. At least that’s what it means in photography, but this sounds like the same sort of thing, with the vertically polarised white light going through the slits in the red lens and showing up white, any other polarisation of the light including random will not go through the slits and will be tinted red by the red lens. The neutral density layer on the outside makes the whole taillight look red except when lit up from behind, when it goes red or white depending on the polarisation of the light, I THINK, not totally sure because I do more stuff with photography than 968's taillights.
