Coloured ink writing using pens - uses colours which can be changed after writing by application of special bleaching fluid

摘要

A method of achieving a wide range of writing ink colours from a relatively small number of pens uses a special bleaching fluid. Each pen, which can be of the fibre up variety, is filled with a special ink which writes in one of the following four colours, violet, brown, black or red. A pen filled with the bleaching fluid may then be used to go over the written words. The bleach causes the violet to change to blue, brown to change to green, black to change to orange, and red to change to yellow. Thus only five pens are required for writing in eight different colours. Formulae are included for the recommended proportions of dyestuffs, bleach, water, etc. for each ink.