An artist's workshop in which the canvas can be painted in any colour, and where painterly names for pigments ("cerulean") are accepted alongside everyday ones ("blue").

There are hundreds of traditional pigments, from lampblack to burnt sienna, so we will confine ourselves to just two:

"Palette"
The Atelier is a room. "The floridly untidy loft space used by a moderately unsuccessful artist (you, that is)." The canvas, palette and paint brush are here. Understand "painting" as the canvas.
Colour is a kind of value. The colours are white, red, blue and green.
The canvas has a colour. The canvas is white. The printed name of the canvas is "largely [colour] canvas".
Painting is an action applying to one thing and one colour. Check painting: if the noun is not the canvas, say "Centuries of tradition suggest that canvas is the natural home of paint." instead. Carry out painting: now the colour of the canvas is the colour understood. Report painting: say "You splash away at the now [canvas]."
Understand "paint [something] [a colour]" as painting.
Understand "calico" as white. Understand "cerulean" or "cerulean blue" as blue.
Test me with "examine canvas / paint canvas red / examine canvas / paint canvas cerulean / examine canvas".
Test me with "examine canvas / paint canvas red / examine canvas / paint canvas cerulean / examine canvas".
Atelier
The floridly untidy loft space used by a moderately unsuccessful artist (you, that is).

You can see a largely white canvas, palette and paint brush here.

>(Testing.)

>[1] examine canvas
You see nothing special about the largely white canvas.

>[2] paint canvas red
You splash away at the now largely red canvas.

>[3] examine canvas
You see nothing special about the largely red canvas.

>[4] paint canvas cerulean
You splash away at the now largely blue canvas.

>[5] examine canvas
You see nothing special about the largely blue canvas.