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Processed Solar spectrum from a full-spectrum modified Canon 40D, using a home-made holographic diffraction grating.
Processed Solar spectrum from a full-spectrum modified Canon 40D, without (top) and with (bottom) an Astronomik Proplanet 742 IR filter. These were recorded using a home-made holographic diffraction grating.
Lumanance (black) and RGB data from the spectrum of a modified Canon 40D (clear glass filter modification). Note the dip in the peak of the luminance. This is due to the absorbance of the brown-orange stained emulsion from the potassium dichromate bleaching solution.
This graph contains the same luminance spectrum, but also has detail of the spectrum obtained with an Astronomik Pro-Planet 742 IR filter.
The set-up of the Spectroscope-in-a box.
Razor blades used for the slit. Close & parallel spacing was achieved by using a 0.002" piece of shim stock as a spacer, between the blades.
The Camera-end, with a view of the holographic grating inside.
The Top spectrum is the full spectrum from a full spectrum Canon 40D, using a homemade transmission holographic grating. The bottom spectrum uses the same camera and grating, but includes the Astronomik Pro-planet 742 IR filter (hopefully aligned correctly). It may appear that the spectrum (with the filter) extends further in the IR, but it's just a difference in exposures of the two spectra. These are raw, unprocessed spectra.
This is the histogram of an IR image shot at 742nm. This image used a custom white balance. Notice the Histogram contains all primary colors.
Custom White Balance on 740nm IR filter
Notice the balanced histogram in RGB, when using a CWB
Daylight White Balance on 740nm IR
Notice the huge imbalance of the Red values on the Histogram, when not using a custom white balance for IR. Generally, these images are more difficult to process, especially if the color swap method is desired.
Camera LCD with Custom White Balance & 740nm
Notice how easy it is to visualize the scene, with a CWB
Camera LCD with a Daylight White Balance & 740nm
Trying to compose a scene is much more difficult when viewing the IR image like this:
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