Specific Diffusion Question

[JAAM]

Sorry for the likely repeat but I could only find vague answers.

For some background I built a 2W 445nm laser a few years back and religiously wear goggles when using it for anything other than pointing it at an empty clear sky.
I understand that diffraction can be a safety hazard at high powers and is based on distance from the laser "dot". I keep seeing conflicting information on whether or not wavelength matters.

I'm about to be putting together a RGB laser for fun and show and was curious what is viable from a safety perspective.
The RGB module I found has 2 wattage options

300mw (638nm@100mw, 505nm@100mw, 450nm@100mw)
and
800mw (638nm@180mw, 505nm@100mw, 450nm@520mw)

I understand that neither of these are safe for direct eye exposure however I was wondering whether the 800mw variant would be a diffraction hazard at 5ish ft from the dot.

Ideally I'd like to use the more powerful module for a more vibrant color but if everyone needs goggles on it defeats the point of the build.

 

[Mattronium]

Do you mean reflection instead of diffraction? For the most part, for visible lasers, the danger is from power (and power density, irradiance) not wavelength.
Aside from the obvious danger of a direct hit to the eye, the second danger is from specular reflections. The specular reflections depend on what surface the laser hits. Are you planning on using the module like a pointer or mount it/keep it mostly stationary?

 

[JAAM]

Sorry to clarify I was asking about the safety of looking at the dot on a non reflective surface from 3-5+ feet away
Ideally the laser would be a large battery powered handheld