Value = the Lightness or Darkness of a colour.

To Brighten a colour paint its complementary colour beside it.

Complementary Colour – Combining a shade, tint or tone of one colour and the colour opposite on the colour wheel.

When two tones far apart from each other on the value scale are selected for example dark brown and cream,  and these tones are painted right beside each other, sharing a common edge, then that pair of tones are said to be in HIGH CONTRAST.

High- Contrast  pairs of colours appear to come forward, while Low-Contrast pairs of colours appear to recede

In this photo below …

1) I have mixed a blue background, and painted the korus with Van Dyke Brown and Titan Buff.

2) When paint is dry I have made up the background colour and mixed this with a glazing liquid and painted over the Korus that I wanted to appear to recede into the background.

Contrast colours with values …