According to all the rules of law and logic, you are committing a breach of contract already.

Stop! let's have a look at your paints.

Are they the best quality?
If not, I warn you, sir, there's a second breach of contract! Brushes, too?
Why, they're old brushes, by the Lord Harry! The Town Council pays you well, Mr.Artist; why don't you work for them with new brushes?
What?
you work best with old?
I contend, sir, that you can't.

Does my housemaid clean best with an old broom?
Do my clerks write best with old pens?
Don't color up, and don't look as if you were going to quarrel with me! You can't quarrel with me.

If you were fifty times as irritable a man as you look, you couldn't quarrel with me.