diminshed blue or green in vision (too much 445nm?)

I wouldn't look anywhere in the vicinity of a laser dot coming from a class 4 laser. After all, that's the main criterion that separates a class 3b from class 4.

Well, the separation is not that big is it? It would be silly to state that the dot from a 499 mW laser is always perfectly safe to look at, while that of a 501 mW laser never is.

The class-4 boundary was set at the point where laser beams generally become a fire hazard, it doesnt have much to do with eye safety at this point anymore (we passed that when going over 5 mW long ago).

As for doing actual measurements on the power of reflections: kudos! Provided the sensitive size of the meter is as large or larger than the pupil and it can detect 1 mW, this does prove a point. Just to see what happens with glossy things: try bouncing the beam of a regular window into the meter and see what reading you get... that should be a few percent of the laser power.

^^^Kind of wish I remembered what thread I posted the results in.

One of these days I need to get a better lpm to test with. The surface area of the thermopile is four times larger than the pupil iirc, but I think I accounted for that.

Next weekend I have no plans I'll do some more experimentation. Regardless of the results... I try to never look at a dot from closer than 5 feet, although it has happened a couple times from about 18 inches.

I woulnt recommend to look at the dot from close up, but your measurements show that there is little danger, only discomfort. Then again, my logic is not to look at something when it hurts if you try to.

very interesting reading material
:thanks: