Griffin Dyeworks & Fiber Arts

Understanding Mordants and Modifiers

Oxalic Acid


Description: Acid modifier, white odorless crystalline powder found naturally in some plants; laboratory produced, 1.6 pH in solution, isolated in 1776. Found naturally in plants: wood-sorrels and that pesky lawn weed, oxalis.
Other Names: Acid of sugar, ethanedioic acid, oxalis, oxalique
Dye Use: Bleach for flax; discharge and oxidizing agent; alum and copper mordant fixative; precipitates yellow out of green to leave blue. Used in some indigo vats. Old dyer's notes say fiber mordanted with oxalic acid must be stored a month before dyeing with a blue dyestuff to get blue color; otherwise fiber will be brown if dyed before that time.
Best On: Wool, silk as a pre-mordant
Dye Recipe: Add 1 tbsp to 1 gal water, simmer fiber 1 hour
Safety: Poisonous acid; destructive to mucous membranes, eyes, can be absorbed through skin. Ingestion can cause death. Heating can cause toxic gas, so wear respirator and do not breathe fumes.
Disposal: Pour down toilet or sink
Alternative: Potash, plants that contain oxalic acid: oxalis, shamrock, wood sorrel (Oxalidaceaae), rhubarb, dock
Source: Griffin Dyeworks

CODES: c = cup; gal = gallon; lb = pound (weight); tbsp = Tablespoon; tsp = teaspoon / [AF] Anglo-French; [Ar] Arabic; [AS] Anglo-Saxon; [Dan] Danish; [Du] Dutch; [Fr] French; [Ger] German; [Gk] Greek; [It] Italian; [L] Classical Latin; [LL] Late Latin; [ME] Middle English; [ML] Modern Latin; [OE] Old English; [OF] Old French; [ON] Old Norse; [OS] Old Saxon; [Port] Portuguese; [Sp] Spanish; [Sw] Swedish / CE = Common Era; BCE = Before Common Era

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