5.1. Basic Principles
Shave the surface of the plywood board by the blades of the cutter for removing oil.
Do not use sandpaper: it would fill up the grain of wood.
Draw an image on the surface of the plywood board with the oil-based acid-resistant mediums.
Do not use any powder like talcum powder and resin:
it absorbs size, makes solid and sticks to image, as the case may be,
it would be hard to remove the image by solvents for making printing plate.
Size plentifully on the surface of the plywood board a few times.
It needs filling up the pores of wood with the wood-filling because the structure of wood is porous and lets water through too much.
Size soaks into the plywood and fills up the pores of the plywood board.
Apply the size 3 times for lauan (Philippine mahogany) and a time for tilia japonica.
Do not apply the size too many times: it would deaden the grain of wood.
Dry the size securely.
The starting temperature for gelation is 18-20°C (64-68°F) and the time required for completing gelation is 8-18 hours.
The size which coagulated once is not water-soluble.
Apply a weak acid solution of gum arabic in water plentifully on the surface of the plywood board after drying size.
It soaks into the plywood.
The fat of oil-based drawing mediums is resolved by arabic acid, and fatty acid floats.
It is lipophilic but still unstable and weak, and for filling in the pores of the wood, it needs replacing fatty acid with the lacquer.
It is better to put ink uniformity on solid interior image.
It is possible to use the silicon instead of the lacquer; cheap and easy parts the ink.
The surface of the blank space on the plywood board is hydrophilic and has the property of keeping water.
The porosity of wood is easily permeated with water.
Furthermore, it seems the fiber of plywood board is catching gum arabic still.