What color is an electron?

Here's a picture of an electron beam outwards from the negative grid of my Fusor.  The vacuum was about 50 micron at the time.

So, are the electrons blue, or just the residual nitrogen ions lighting up as the electrons head to the positive grid?

Here's a picture of an electron beam outwards from the negative grid of my Fusor.  The vacuum was about 50 micron at the time.

So, are the electrons blue, or just the residual nitrogen ions lighting up as the electrons head to the positive grid?

Very cool image.

Presumably it is electrons changing energy states and giving off photons, whether they are in the electron beam or interacting with nitrogen ions.