Every picture is a collection of units or items.
Every unit has a given value.
The value of a unit depends on its attraction; its attraction varies as to its placement.
An isolated unit near the edge has frequently more attraction than at the centre.
Every part of the picture space has some attraction.
Space having no detail may possess attraction by gradation and by association.
A unit of attraction in an otherwise empty space has more weight through isolation than the same when placed with other units.
A black unit on white or a white on black has more attraction than the same on gray.
The value of a black or white unit is proportioned to the size of space contrasting with it.
A unit in the foreground may have less weight than a like one in the distance.