This wasn't as time consuming as I thought it might be.
Reference this image:
This image was taken with the Optolong L-eXtreme H-a / OIII filter.
The first image illustrates what happens when you have only H-a and 0% OIII. Hue is fixed, Saturation is fixed and Brightness varies from 0-100%. The only details you can see are the brightness differences your eye can differentiate in pure red. The human eye is not particularly good at this.
The second image illustrates a normal H-a / OIII image when the image data is equal in the green and blue channels. A photo of the moon will produce a normal grayscale image. Hue is fixed, Saturation is 0-100% and Brightness is 0-100%. In this image varying two of the three HSB parameters produces an image in which we can see more subtle detail.
The third image illustrates a small non-linear stretch to the blue channel which introduces a small shift in hue. Instead of pure red, the hue now varies from 330° (magenta) to 360° (0°) (red). I'm betting most people will find this image a bit more appealing than the red only hue of the second image.