A red filter + a blue filter in theory produces black.
Well in the pictures, I can see reddish tones, and I can see bluish tones. That’s the basic reason I’m asking for confirmation.
Oh, look. I’ve found the flickr artist discussing his post-processing procedure: bar exam: civil procedure | 0 IR original 1 auto level 2 swa… | Flickr
The image starts out quite drab, and the color is added.
And here is the description of how the goggles work:
I had read that as well, on the site. I wanted to know how that process could have produced the pictures he was showing me. At flickr, you’ve found what looks to be a decent explanation. Thanks!
-Kris
I’ve always thought it would be great to have UV vision and go to Vegas and mark the cards with UV-absorbing ink. You could write the identity of the card on the back.
Note: don’t actually do this; it would be illegal, and get you thrown into jail (or worse).
Ah, that’s because I shot those photos using a stack of five Congo Blue filters, but no red filter to remove the blue leakage. If you include one or two layers of Primary Red, then the image should appear purely red. (But also, some cheap webcams have crappy color filters, and will see infrared light as blue or cyan.)
“Even better $10 IR goggles” use goggles with a flip-down lens. That way you can install the Congo Blue stack in the main goggles, then place the Primary Red in the flip-down lens. In low-light environments it helps to let in some visible blue (since a total lack of IR makes you temporarily blind.)
It does. I mis-typed.