From mint media

Photolac photostencil emulsion with Dichromate sensitiser.

Add sensitiser to emulsion in 5% (1:20) proportions.

Here is some more detail about the process of applying photo emulsion.

Mix up the emulsion with the sensitiser.

Try to leave your sensitised emulsion for about 20 minutes to allow the bubbles to clear. The cooler the atmosphere the longer this will take.

Coating the screen with emulsion. I used a 45 degree angle. Note the bubbles.

Screen after coating.

Once you have a nice even coating on both sides of the screen you can set it aside in a dark place to dry. Always dry flat.