Often we need to use transparent colours for one of Bob's creations or one of our own, mostly they are to be used over black gesso.
In search of a list of oil transparent colours, I stumbled upon two versions. One is Bob's own list, as you can find here:
The other information comes from a general article of an oil paint manufacturer that informs his clients the following:
"All paint tubes contain an indication, on the tube itself, in the form of a little square. Is that square open or blank, the colour is considered transparent. Is it open yet has a slash/backslash running through it or is it semi coloured, it is considered semi-transparent. Is the square black or filled up, it is non transparent".
See the example below:
As Bob mentioned several times in his episodes, you will know if it is transparent enough when you put some paint over black gesso and it does not clearly show. It will be there, but not clearly visible.
In general, the most frequent transparent colours are:
Phtalo blue, Prussian blue, Phtalo green, Sap green, Indian yellow, Alazarin crimson, midnight black.
All the rest that Bob uses are semi-transparent, opaque (Titanium white) or semi-opaque (Van Dyke brown).
If any comments or errors, please drop me a message!