This is a link to my review of the Wurkkos WK40, an interesting 21700 format RGBW flashlight, with quad optics.
The review contains plenty of photos, including me using it for light painting photography.
How does it compare to other RGBW flashlights? Read on…
thank you for the review, nice photos
Wow, lotta nice detail in there (beam angles, emitter types, etc.)! 
Surprised, you got a 6500K white? Mine’s definitely on the warm side, at least 4500K, ’though deep red is rather subdued.
I had no idea so much went into light-painting, eg, that LMM would be important for, say, color strobes or gradient, but it makes perfect sense.
Thanks. Yes, a lot goes into light painting. We have very different UI requirements to many flashlight users.
Can anyone tell me which TIR optic they used? Would like to change it into a floody one. Thx!
Better to just slap on some diffusion film? Way cheaper, way way way way way easier, and reversible as well.
I got a “tactical” light that has a pretty tight beam, but ringy, and figuring I’m not going to be tacting anywhere soon, slapped on some diffusion film, and now it’s a great “go down the basement” light with its smoother floodier beam.
Hm youre right. I think i’ll do that. Besides Wurkkos replied that they use a custom lens, so no idea which would fit 
For an RGB lights it is pretty throwy. I think it is 20 degree optics, but not sure. Some D C Fix will make it more floody if required.
Plus, there are different grades. Some are barely hazy and can be good or fixing up some rings and other artifacts, whereas the really diffusey ones will turn a pencil-beam almost into a mule.
My Tacklife and a bunch of LuxPro lights all use the hideous G3s, about as fried-eggy as you can get. Hideous hideous beams, even though nicely throwy. So I slapped on diffusion film I had on hand (not DCFix but quite good) and it fixed ’em all up. The LuxPros I swapped the front plastic for real glass as well as put film on behind the glass, so it didn’t need to be the adhesive kind. Same for the Tacklife ’though I’m pretty sure it already came with glass and not plastic.
Putting it behind the lens lets you get away with using the nonsticky film by wedging it between glass and reflector.
My Xeno E03 is pretty good, beamwise, but for indoor use (it always comes on in medium, ugh), it’s a little too throwy, so I just cut a nonsticky disc and somehow it actually got “caught” between bezel and O-ring, so it sits there precariously but hasn’t fallen off yet. If I wanted to, I could always swap the sticky kind and slap it on top.
If you just want a little blur, try scotch-tape. Put a layer across 1 emitter and see how it looks. Then you can slap it across everything and trim it to fit.