Classic Poem

In picture, they which truly understand,
Require (besides the likeness of the thing)
Light, posture, heightening, shadow, colouring,
All which are parts commend the cunning hand;
And all your book (when it is th'roughly scanned)
Will well confess; presenting, limiting,
Each subtlest passion, with her source, and spring,
So bold, as shows your art you can command.
But now, your work is done, if they that view
The several figures, languish in suspense,
To judge which passion's false, and which is true,
Between the doubtful sway of reason, and sense;
'Tis not your fault, if they shall sense prefer,
Being told there, reason cannot, sense may err.