Spray mounting adhesive onto the back of your photographic print. Lay it onto a wooden board of exactly the same dimensions as your photograph. The wooden board gives strength to your print, which is necessary because the encaustic is heavy.
Roll the entire photograph with a brayer, starting from the center and working outward, to remove air bubbles. It also helps the print adhere to the wood backing.
Melt beeswax with damar resin, which is a hardening agent, in a small pot over the stove. Dip a stiff bristle brush into the melted wax mixture. Apply the wax to a small area on the photograph that you want to encaustic paint.
Add oil paint mixed with glaze -- made from linseed oil -- where the melted wax was brushed, using another paintbrush. Brush more wax over the area, if necessary, and apply more oil paint mixed with glaze.
Brush on the wax mixture to another area of your photograph. Apply a mixture of oil paint and glaze. Continue this process until you are satisfied with the results.