Even if JYD is informing of only some shades of blue I still claim the possibility to use the color chips I found. All those chips have been issued by Acme White and Color Works, Detroit, MI. So, in my mind no doubt about where I have got the information and where it would be used (in USA).
F.ex. Fernandez Blue has this mixture:
16 parts Proxlin Basic Tinting Prussian Blue No. 810
7 1/1/4 parts (same type paint) Umber, No. 829
6 parts " " Black, No. 895
3 3/4 parts " " White, No. 556, 33 parts in all.

