Sizing the silk

It seems there is a solution to the silk bleed problem. People who paint with dyes on silk first 'size' the silk with various chemicals. These agents fill the gaps between the fibres and stop the spread of ink. After it has been steam set, the sizing is then washed out if the silk. Also the silk should be stretched on a frame.

I'm not sure on the traditional Japanese sizing recipe, there was mention of a specific ratio of alum and glue but I'll be happy if I can find some commercially available solution.