1. Place 2 slides between the rollers and adjust pressure.
2. Remove the slides, decrease the gap with dials.
3. Place the fish scale between the sides, run it through.
4. Increase or decrease pressure as needed.
6. Reuse the slide covering the scale over and over again.
“In our experimental work with the roller press, we sought to obtain a light impression in which the finest features of the scale, including the thin outer margin, were replicated. We are confident of having produced an impression which casts a projected image with features as fine and accurate as those from the scale itself and, in some instances, with less objectionable light refraction.”
From Smith, Stanford H., Method of Producing Plastic Impressions of Fish Scales Without Using Heat.