Only getting color at top of image
Thanks to everyone for their suggestions on my "black image only" spectrometer! Turns out the DVD-R piece I received was damaged.
I've now used a fresh piece of DVD-R, and while I'm getting a lovely rainbow of colors, it's only at the top of the image. Spectral Workbench can't seem to use it; it only sees the blue bar in the middle of the image.
I assume I need to move something inside the spectrometer, but what?