This post shows three examples of full spectrum mapping methods for multispectral photography. I’ve used some quick shots I took inbetween rain clouds so I apologise for the poor quality – especially the infrared image. All shots taken on a converted D70.
Infrared (720nm filter)
Visible light (Hoya cut filter)
Ultraviolet (Baader-U filter)
The only map I see often is the classic3to3 map. The characteristics are so that vegetation stands out in a very prominent red, nectar guides are clear cut and clear skies are a strong blue. The next map is weighted, roughly, 5to3 on the proportionalspectrum each [I,R,G,B,U] component covers as wavelengths. The output shows the nectar guide enough for it to be noticeable, but clearly less so. The last map is my favourite so far, it is a 5to3 map that distributes the [I,R,G,B,U] in equalproportions. It dulls the bright red vegetation caused by infrared in the red channel and shows the nectar guide a little better than the previous map.
Channels & Output
R: (IR + IR + (IR * 0.33)) * 0.42
G: ((IR * 0.66) + R + (G * 0.66)) * 0.42
B: (UV + B + (G * 0.33)) * 0.42
This post is to show one of the features of WavelengthPro, some photography software I’m writing at the moment. It’s in early stages at the moment, I hope to add a lot more.
Channel Map Templates
I plan on having a basic and advanced way of mixing channels, so far I’ve done the basic version where you choose template maps. The advanced version will use percent sliders of every channel for every channel just like in Photoshop or GIMP etc. Below is a table showing the three starting images (all taken on a full-spec D70 using 720nm, Hoya UV/IR cut and Baader-U filters) and some of the possible mixtures using the program.