The wavelength being generally in X-coordinate, it is simple to extract with an appropriate software the column λ from all the images from the stack and to juxtapose them to obtain a monochromatic image.
Here is, for example, an image in the continuum (left) and one in the center of Hα (right), both extracted from the video.
It is then easy, knowing dispersion in Å/pixel, to select monochromatic images to highlight the radial movements of plasma by measuring the Doppler effect. Below, the subtraction of 2 images in Hα-0.5Å and Hα+0.5Å gives the Doppler image coloured which shows important movements in the filaments. This technique will be also very usefull to go into the construction of magnetograms.
A DSLR having a video mode can also be used for this kind of imagery. Its broad sensor makes it possible to record the Sun in entirety. However, compression is very important and finally the image has a poor dynamics. Here is a Hα test done on July 28th, 2010 with a DSLR Canon 450D. The dark zones on the right are due to the passage of clouds.
The movie in the movie
If, instead of extracting only one or two monochromatic images from the stack of spectra one extracts a large number of consecutive images and that one assembles them in animated GIF or AVI, one obtains a movie of a solar area with a wavelength variation.