Question

1. Why is blue or purple toner added to white paint?

Answer 1

Blue or purple toner is added to white paint to achieve deep tones and create subtle gradations in oil paintings.

Step-by-step explanation:

Blue or purple toner is added to white paint to achieve deep tones and create subtle gradations in oil paintings. Venetian painters would prepare a panel with a smooth white ground and build up layers of oil paint. Since oil paint dries slowly and stays somewhat translucent, the thin layers reflect light and create a shining surface. Additionally, some painters, like Bellini, Giorgione, and Titian, would add ground-up glass to their pigments to better reflect light.

Answer 2

Step-by-step explanation:

Defining whiteness is one thing, popularising the white so defined is another thing. There are different shades of white, which become popular at different times and in different regions. There is almost no such thing as a pure white paint, the whiteness of which is universally accepted as true!

For some time, a blued white was considered desirable, when white garments used to be blued, since the bluing camouflaged the yellowness that most whites tend to acquire on aging.

Adding a specific shade of pink was considered the whiter white for some time. Then came the violet toners which reigned as whiteners.

The so called optical whitening agents do make surfaces treated with it emit extra light making the surface appear whiter than before, at least for some time.

Similarly, adding an extremely small amount of black / grey colour, may make the surface appear devoid of other conraminating hues, to some viewers.

Any and every such additive works on paint only for some time - weeks or months - after which such whites look dirtier than when without it. In other words, the effect of optical illusion wears off!