The most common and most likely answer to this crossword clue is the 9 letter word REMBRANDT
I've seen this crossword clue in The Times
R
E
M
B
R
A
N
D
T
More clues leading to the result REMBRANDT
- Sword beginning to tarnish beneath rising sea in French painting
- Art master’s responsibility, taking class for one
- Artist to overhaul image — time to grasp medium
- Artist using eye movement to mark conclusion of portrait
- Canvasser’s terms of reference: to place an indelible mark for one
- Note to Frenchman, former German chancellor and artist
- Involuntary behaviour leading sometime chancellor to painter
- American rockers make time for artist
- Dutch superstar band leader Willy
- Artist runs line through space and time
Buddy explains!
The straight part
We know that "Canvasser" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case canvasser = rembrandt.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.