Pretreat materials in a vinegar/later soak To make natural dyes: Yellow– yellow onion skins, turmeric (1/2 tsp. per cup water) celery leaves Orange–any yellow dye plus beet juice Red–beets, paprika, red onion skins Pink–cranberry juice Blue–blackberries, grape juice concentrate, red cabbage Brown–black tea, white oak, juniper berry, coffee, barberry Light purple–blackberries, grapes, violets Green–alfalfa, spinach, kale, violet blossom plus 1/4 tsp. baking soda, tansy, nettle, chervil, sorrel, parsley, carrot tops, beet tops or dip yellow material in blue dye Place dying ingredients in non-aluminum pans, cover with water and boil 5 minutes to 1 hour until desired color is achieved. Use enough material to make at least 1 cup dye. Crush ingredients as they boil to extract as much dye as possible. Strain the dye. Most dyes should be used hot. Submerge material in hot dye preparation and stir occasionally as you let the material sit until it reaches the desired color. Some dyes will take longer than others to make the desired color. Remove and let dry.
Clarification please: Soak treated materials in vinegar later after dyeing or soak them later in something else ? OR Pretreat materials in a vinegar & "something else" soak ?
Sorry for this lack of clarity - Pretreat material with a vinegar and water soak, boil the dyeing agent in equal parts vinegar and water, strain the dye then boil the material in dying medium. Remove from dye bath and dry material. This is the method I used and had good luck but don't count on the intensity of the dye to remain. My experience has been that the dye fades with washing but then you have a new color or hue to enjoy