On the right is a photo of British explorers taken with orthocromatic film. Note the red on the flag is much darker than the blue area because the film isn’t receptive of red light. Looking at the spectral sensitivity (here) and (here) it’s clear the violet/blue area is the predominant band with it extending to green/yellow as well.
I took an image from Google, something with the British flag, and made different Channel Maps for it. The greyscaled versions are the output images.
I used the QSE tool on WavelengthPro to make a 400nm image (the violet/blue peak) and a 580nm (the green/yellow peak) and made a 2to3 map of the peaks, the colour response worked well but the data-loss from interpolation was too much. Using the original [R,G,B] channes means I won’t lose any detail, so I tried using mainly those and came up with two maps that were pretty good – GBB and GBBV. Below are those maps and the RGB map for comparison.
This is the RGB (panchromatic) version, the red cross on the flag is lighter than the blue parts and the sky is dark.
This is a GBBtoRGB version, the cross appears darker. It’s not really true to the actual spectral response of the film.
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.
Ok this really is an idea that’s fresh in my head, i couldn’t sleep and this
started swimming around..
Multi-Spectrum Imaging: Quantitively assigning the entire EM
spectrum to a corrasponding RGB value and building some sort of multifunctioning
camera that can capture all the different types of shots then transform them
into this image.
An added thought was to assign shades of gray to the entire
sonic spectrum then apply this ‘shader’ to the same image..
Purely experimental, but if it could be done would demonstrate ways of
visualising multiple areas of electromagnetism at the same time.