Fun with tint mixing
Hank did a huge favor for me by putting up with my silly requests. He made a custom D18 for me with four different types of emitter — 3x3000K, 6x4000K, 6x5000K, and 3x6500K. The overall result worked out to about 4200K or 4300K, I think, and has a lower duv value than any individual tint would have. In effect, the beam is less green and more pink than it would otherwise be.
Top: The concept image I made from Hank’s photo.
Bottom: What arrived in the mail. Hank must really like me to go through this much trouble.
(photo was taken with the light in moon mode, which maximizes the visible coloring… so it wouldn’t actually look like this during use)
Artificially saturate the colors, and it looks like this. I like the flame tendril effect these emitters have in these optics:
This shot next to the M43 shows how it looks when the light isn’t even powered on. It’s still clear that there are different tints in a spiral pattern: (this photo is not edited, except to crop it and add a watermark)
When it’s on, it’s not noticeable that the beam is made of different tints, unless I look directly at the light itself. From the side, it looks like this:
Here’s another shot, taken at a somewhat higher level. This was actually in a pretty bright room, but the camera’s exposure was so short it looks like it was taken in the dark. I did not mess with the colors in this picture… I just set the camera to “daylight” white balance and forced it to do a very short exposure to make sure it wouldn’t white out the bright parts.
Not every emitter has exactly the same Vf though, so the brightness varies from one LED to the next. This is normal and expected, but looks bad in a picture. So in GIMP, bring up the brightness of the emitters which had slightly higher Vf…
Then saturate the colors with the “hue & saturation” tool…
… or just put the original image through the disco machine and we get all sorts of candy colors:
During actual use though, the beam is white and about 4200K or 4300K. It looks better than any other SST-20 light I’ve tried.
For more information, mattadores started a thread about D18 tint mixing.