Incorporating the ground tone into the finish.
For this portrait vignette artist Samuel Edmund Oppenheim employs the tone of the ground as the highlights of both face and hair. Here marked in blue~
In the following landscape Daniel Garber uses a coloured ground as the home tone for his colour scheme.
Note just how generously the ground is left bare. Again, here marked in blue~
Nearly every canvas by illustrator J. C. Leyendecker incorporates the ground tone.
In this detail the ground tone is left as the collars local and used as a neutral within others (locals).