A simple homemade silver-gelatin emulsion is typically based on silver nitrate plus a halide such as potassium bromide in a gelatin base. From the community replies, the most consistent references point toward potassium bromide/silver nitrate formulas, though exact mixing methods and lab technique vary.

Useful starting references mentioned were:

• Mark Osterman’s dry plate emulsion recipe
• silver gelatin unwashed emulsion formulas
• simple silver-based photographic emulsion methods for coating glass or film

Those kinds of recipes are appropriate if you want to coat your own surfaces rather than use standard photo paper. Expect the exact procedure to matter a lot: temperature control, order of mixing, cleanliness, and safe handling of silver chemistry all affect the result.

So yes, this is feasible in principle, and the best answer from the discussion is to start with established gelatin-silver recipes based on silver nitrate and potassium bromide, especially dry plate or unwashed emulsion references, then adapt them for your chosen coating surface.