What's primer for?Why is it white?

Answer 1

In art:

Primer is used to make a surface where your paint will stick by itself. Painting on raw canvas needs some real work as it does not take the paint well.

Primer (Gesso) is a mixture of glue and chalk...well it has become a bit more complex but that is still the best way to describe it. It has the combination of two properties:
1) The glue sticks very good to the canvas (and any other surface you can think of)
2) The chalk gives a nice, smooth and perfectly paintable surface.

It is white because of the chalk. Many painters start by giving the whole thing a new under-painting (blue, siena, umber or even bright red) but white is a good place to start for any work.

In home painting:

Primers come in al kinds of colors. The use is still the same: To make an optimal bond between the surface and your top coat(s).

Answer 2

Primer is a base that you apply before you paint, that way the color you paint with comes out as the color you want and not mixed with the color that you painted over. Primer is white because white does not show through.

Answer 3

Primer is basically paint that sticks to anything and is used to prepare a surface ready for normal painting
it can be used on practically anything, except metal (you have to buy a special primer for that)
white is opaque and so will not show through whatever you put on top

Answer 4

Primer is an undercoat in painting. it's white so that it covers wherever colour was already there & leaves a "blank slate" for a new colour to be painted over with nothing bleeding through from below

Answer 5

its a nutral color and it is flat so it fills the pours and allows a base for the finish coat to adhear to

Answer 6

because white is a neutral colour and anything can be painted over it.