
1) Painting technique
Found on
https://www.crosswordclues.com/clue/underpainting

In art, an underpainting is an initial layer of paint applied to a ground, which serves as a base for subsequent layers of paint. Underpaintings are often monochromatic and help to define colour values for later painting. There are several different types of underpainting, such as verdaccio and grisaille. Underpainting gets its name because it is ...
Found on
http://en.wikipedia.org/wiki/Underpainting

Layer of colour applied to the ground (painting surface) before the application of the overpainting, or final coat. Underpainting may be a simple tint to colour the ground, or a blocked-out image...
Found on
http://www.encyclo.co.uk/local/20688

The first, thin transparent laying in of colour in a painting.
Found on
http://www.encyclo.co.uk/local/21274

The first, thin transparent laying in of colour in a painting.
Found on
http://www.encyclo.co.uk/local/22428

The traditional stage in oil painting of using a monochrome or dead color as a base for composition. Also known as laying in.
Found on
http://www.modernsculpture.com/glossary.htm

The traditional stage in oil painting of using a monochrome or dead color as a base for composition. Also known as laying in.
Found on
http://www.rexart.com/glossary.html

The first, thin transparent laying in of color in a painting
Found on
http://www.watercolorpainting.com/glossary.htm

A preliminary toning of the surface to be painted, often somewhat more detailed than a toned ground.
Found on
https://pixel77.com/glossary-design-beginners-50-color-related-terms/

Layer of colour applied to the ground (painting surface) before the application of the overpainting, or final coat. Underpainting may be a simple tint to colour the ground, or a blocked-out image of the composition in diluted oil paints, often in monochrome (one colour). The artist uses the underpainting as a guide while developing the composit...
Found on
https://www.encyclo.co.uk/local/21221

the first coat of paint, esp. the initial painting on a canvas in which the major areas, tones, colors, and forms are indicated in mass.
Found on
https://www.infoplease.com/dictionary/underpainting
No exact match found.