I have a clip on shop lite with the metal reflector around it and a 100w bulb clamp onto the side of my desk and a brown paper box upside down that sits over the lamp it cover the metal reflector so no lite escapes around it and a 1 inch whole in the middle so the lite can come thru, the hole has to be perfectley round no cracks or oval shape anywere.
any lite escaping will make it hard to see your eyes will focus on the lite not the egg.
I can see every egg I've put on it nomatter how brown.
I have a different box with a smaller hole I slide over the lamp to check my quale eggs works great.
just don't forget to turn the lite off after your done a papper box that close to a 100w bulb could start a fire if left for a while.