Comparator with double vision

[Steve@Reliance]

I picked up an older J&L PC-14 comparator and it has a bit of a double shadow. I'm not sure what I should be adjusting to get rid of this. Anyone know?

[easymike29]

Is the light source in a vertical apparatus in front of the comparator, that is you place the object to be measured between the light source and the back lens?

Gene