Spooner's game escapade is material for artists (9,5)
I believe the answer is:
cartridge paper
'spooner's game escapade' is the definition.
I can't tell whether this definition defines the answer.
'material for artists' is the wordplay.
I cannot quite understand how this works, but
'material' could be 'paper' (paper is a kind of material) and 'paper' is found within the answer.
The remaining letters 'cartridge' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'is' acts as a link.
Can you help me to learn more?
(Another definition for cartridge paper that I've seen is " Stiff material for drawing on".)