I have made a quadrature encoder using IR reflective sensors by printing a strip on a laser printer (Generate encoder strip) and wrapping it around a cylinder. I would like to protect the paper surface and keep it clean while not upsetting the IR reflectivity.

What would be the best method of protection - cling film, stickyback plastic, or some kind of varnish?

 

Protect it from what?

 

I might consider printing it on the reverse of clear film and using a double-sided tape to attach it so the toner is not on the surface.

 

A couple of ideas, sellotape or clear nail lacquer.

 

I have used spray-on circuit board lacquer for similar tasks, always have a can of it just in case, is useful stuff. Not super shiny, probably won't affect operation of your encoder.

 

An art supply store will have a clear acrylic spray used for that purpose.