Before, sorry for my english, i hope you understand
The patent of 1908 to 1910 (3 patents an 10 pages) of Joseph Sury and Bastyns of Wijnegen Antwerpen in Belgium is to obtain 3 layers color with the cyanotype and the gum.
It is the same principe of Sam Wang and Christina Z. Anderson with little difference.
Sury is no a photograph, it work in the chemical industry.
Gustave Marissiaux is a very good Belgian photograph and he test the process of Sury.
All the colour picture of Gustave Marissiaux is made with the process of Sury of 1908
It is a picture of Marissiaux with the process of Sury.
Sorry the scan of the book is no good but it is a idea, it is a reproduction
It is on my web site a few days.