@PJ Flannelman has a good point with a timer. I do a PWL pictures as you discribed it but I have a cable realese so I have a bit of the freedom to move to switch a light of and get back to the camera.

About the orange coloration of the light. Is it possible you can change a bulb to white fluro? You know, those curly funny looking bulbs. That would give you a nice white but cold light. The good thing in those bulb they allready diffused if you after the nice even light.

@Bruce What do you mean by light painting? When you outline your (any) car with a flashlight or when you pointing a flashlight in different areas on a set/subject. It can be a barndoor too not just still life.

seeya  Tunde