Renata is the Elf-Directress-of-Colors-and-Dyes at the North Pole. She uses sunflowers for soft yellow, goldenrod for yellow/beige, wild rose hips for oatmeal brown, blue lupine for green, wild holly berries for pink, and on it goes. This letter has a very 'Waldorian' feel to it.
When a new elf apprentice assigned to the teddy bear department accidentally skids on an onion skin (used to make pale yellow), he sends cans of dye flying everywhere...and Rainbow Bear is created. Maybe you'll find one and make it part of your child's special Christmas morning discovery?