To preserve the colours fresh and clean in painting ; it must be done by laying in more colours, and not by rubbing them in when they are once laid ; and if it can be done they should be laid just in their proper places first, and not be touched again because the freshness of the colours is tarnished and lost, by mixing and jumbling them together ; for there are certain colours which destroy each other by the motion of the pencil when mixed to excess.
For it may be observed that not only is the brilliancy as well as freshness of tints considerably impaired by indiscriminate mixing and softening ; but if colours be too much worked about with the brush, the oil will always rise to the surface and the performance will turn comparatively yellow in consequence.
Endeavour to look at the subject or sitter before you, as if it was a picture ; this will in some degree render it more easy to be copied.
In painting, consider the object before you, whatever it may be, as made out more by light and shadow, than by lines.
Avoid also those outlines and lines which are equal, which make parallels, triangles, &c.
Squareness has grandeur; it gives firmness to the forms, a serpentine line in comparison appears feeble and tottering.
- Sir Joshua Reynolds, Underpaintings
