Coating paper by floating, rod or brush

The three most common ways of coating emulsion onto paper are floating the paper, using a coating rod, or brushing it on. An extract from the book Alternative Photography Processes (no longer available).

Writer and photography / Mark L. Eshbaugh

Floating Paper
 

1To float paper you will need a glass tray that will only be used for photographic chemistry. Pour your emulsion into the glass tray. Wear gloves at all times.

2Fold two sides of the paper so you can hold the paper flat.

3Hold the paper just above the chemistry and gently drop the paper so that it floats on the surface of the chemistry solution. Be careful that chemistry does not get on the side of the paper facing you.

4Gently lift the paper out of the chemistry. Hold it an angle so that any excess emulsion runs off the paper. Again, be careful that chemistry does not get on the side of the paper facing you.

5Gently lay your paper down emulsion side up. Allow coating to air dry in a dark place or blow dry as needed. Dry paper is ready for use.

Coating rod
 

1After mixing the chemistry coating for the chosen process, place rod in contact with the paper along one edge. Pour chemistry along the center of the rod.

2Without lifting the rod from the paper, gently move it back and forth to spread the chemistry along the rod.

3Then in a gentle glide, drag the chemistry across the page without lifting the rod from the paper, then once back again ending where you began.

4Coating is finished when you have a nice even coat with no puddles on the paper. If you have areas that are puddled and too thick it will stick to the negative and permanently ruin it.

Allow coating to air dry in a dark place or blow dry as needed. Dry paper is ready for use.
If you have trouble getting the chemistry to spread evenly along the coating rod, it can be helpful to use an oral syringe and dispense the chemistry evenly along the rod.

Brushing Chemistry: Cyanotype and Gum
 

1After mixing the chemistry coating for the chosen process, pour your emulsion mixture in the center of the page.

2Using a foam brush and swift even strokes, spread the chemistry out in all directions.

3The coating is done when the chemistry is spread evenly with no puddles.

Allow coating to air dry in a dark place or blow dry as needed. Dry paper is ready for use.

Brushing Chemistry: Platinum, Ziatype etc
 

Use a hake brush with no metal ferule so that the metal doesn’t interact with your emulsion.

1With a pencil mark the outside dimensions of the negative to be printed to indicate area to be coated with chemistry.

2Presoak your brush in distilled water. Remove brush from distilled water bath squeeze until damp (not dripping).

3After mixing the chemistry coating for the chosen process, pour coating mixture into the center of the image area to be coated. Paper can be held down on edges with a bit of tape to keep the page from sliding around.

4Use smooth strokes to spread the chemistry to the marks indicating the negative size. Try to keep the chemistry contained into that area. Some papers allow you to easily over spread the chemistry resulting in a weak print.

5The coating is done when the chemistry is spread evenly with no puddles.

Allow coating to air dry in a dark place or blow dry as needed. Dry paper is ready for use.