"I can readily believe," answered he gravely, "that reports may vary greatly with respect to me; and I could wish, Miss Bennet, that you were not to sketch my character at the present moment, as there is reason to fear that the performance would reflect no credit on either."
"But if I do not take your likeness now, I may never have another opportunity."

– Jane Austen

Pride and Prejudice, Chapter 18. Darcy knows that there are varying reports circulating about him and he is not being shown in the best light at the moment. Using a metaphor, he asks Elizabeth not to sketch his character right now as it may be an inaccurate sketch and reflect poorly on them both. Elizabeth has been hinting to Darcy that she heard reports of his alleged cruel treatment of George Wickham.