Police lights

[RichardU]

I need to light up a scene with flashing blue police lights. Don't need to see the fixture. Just need to see the light. I tried looking through a layer with a semitransparent blue rectangle, but it only made the colors look weird.

Any ideas?

[slowtiger]

Adiitionally use a white reflex over the blue, set to screen.

[drumlug13]

Adiitionally use a white reflex over the blue, set to screen.

Slowtiger, do you mean to use it as a "screen" technique or is there a screen setting/tab somewhere?

Richard, I wouldn't be to overly picky about the colors being a little off when the Blue is on. Colors of an object will change quite a bit when there's different colored lights on then (like police or concert lighting) It can still look natural.

[slowtiger]

Layer tab, blending mode.

[drumlug13]

Wow ! I completely forgot that that was there ... Thanks!

[RichardU]

Thanks Slowtiger. I tried to find some documentation on Blending modes and didn't find much. Probably need to know that from using Photoshop or something similar. Anyway, I never would have figured that out.

I ended up using three layers: A black layer set to 30% opacity to simulate evening, a blue layer set to 50% opacity, and a white layer set to 50% opacity with blending mode set to screen. To simulate the light flash, I turn on the blue and white layers for two frames, with the blue layer coming on on frame earlier than the white layer. While the blue and white layers are on, I turn the black layer off. Looks pretty good.

[slowtiger]

Sounds good, not much different from what I'd do.

Try and set the blue to multiply - that's what I do to tint objects temporarily. And you definitely should try colour as well, sometimes that's even better. Depends on colours. Never forget to render to see effect!