The 744T I bought had all dash and instrument lighting changed to red. The PO did it using a heat resistant red film (available I think from professional graphics or photo suppliers). Small pieces - about 2"x2" - were inserted in the sockets before the bulbs. I used a simpler solution with my 945T - I used a red permanent magic marker on each bulb. So far, no smoke, no fire, and only slightly less bright than with clear bulbs; there seems to be enough red in the paint on the gauges to reflect the filtered light.

Jim Weiss
83 245T/M46, 90 744T/M46, 90 760T, 93 945T, want more ...

Actually, changing the bulb color does alter both the final color and the total light output (assuming that the light is already going through one set of filters that's already built into the dash).

White light is comprised of all the colors of the spectrum, however, when you have a filter (or a colored bulb), that filter absorbs all of the light except the color you want to pass. Therefore, a red bulb is only emitting red light, and if you filter it again with some other color (like green), you're going to have basically nothing passing through the 2nd filter, -since the pass-through colors particular wavelength was already removed by the first filter.

A brief overview on the interactions between the primary colors and filtering can be found here: Click here.

God bless,
Fitz Fitzgerald.
--
'87 Blue 240 Wagon, 247k miles.
'88 Black 780, PRV-6, 145k miles.