View Full Version : light beams affect each other?

starry night
04-23-2012, 02:57 PM
What happens when two beams of light cross? Do they continue on as they would without a crossing beam? Do they diffuse? Does any light get re-directed into the (?) area in this drawing. Dotted line is one beam; the solid line is another beam.

knox gsl
04-23-2012, 04:50 PM
I don't think it makes a difference, I've done alot of work around stage lighting and that is common there, I've also seen projectors cross beams and work.

Green Acres Indy
04-23-2012, 07:15 PM
That's only a problem if you are a ghostbuster using a proton pack. "Never cross the streams!"

04-23-2012, 07:48 PM
No affect to either beam. If both beams overlap over a surface, however, it gets more interesting. The illuminance (footcandles) is directly additive. The reflected luminance (the light that reflects back to your eyes), on the other hand, depends on the reflectance and specular nature of the surface - lights coming from different angles will yield a complex visual experience that will vary in brightness depending on the visual angle.