What is "to set the palette"

Palette \Pal"ette\, n. [See Pallet a thin board.]

1. (Paint.) A thin, oval or square board, or tablet, with a thumb hole at one end for holding it, on which a painter lays and mixes his pigments. Hence, any other object, usually one with a flat surface, used for the same purpose. [Written also pallet.]

2. Hence: The complete set of colors used by an artist or other person in creating an image, in any medium. The meaning of this term has been extended in modern times to include the set of colors used in a particular computer application, or the complete set of of colors available in computer displays or printing techniques.

3. Hence: The complete range of resources and techniques used in any art, such as music.

4. (Anc. Armor) One of the plates covering the points of junction at the bend of the shoulders and elbows.
   --Fairholt.

5. (Mech.) A breastplate for a breast drill.

   Palette knife, a knife with a very flexible steel blade and no cutting edge, rounded at the end, used by painters to mix colors on the grinding slab or palette.

   To set the palette (Paint.), to lay upon it the required pigments in a certain order, according to the intended use of them in a picture.
   --Fairholt.