Alum ,Potassium Aluminium Sulfate is the principal mordant (fibre preparation) for bright colors with natural dyes. it is found in nature in crude form of varying purity, often relatively close to the earth's surface. this mineral salt was mined by many early civilizations and valued for it's role in dyeing, in medicine for it's astringent , antiseptic qualities and in agriculture as a treatment for alquiline desert soils.

alum is essentially an acid in solution which is easily absorbed and bonded with protein fibres, but it must be manipulated with chalk and soda towards a more basic nature to be useful for cellulose coloring. overnight soaking in alum mordant is followed by week-long airings of the fibre, during which the fibre/mineral complex 'cures'. this processis repeated, often in combination with tannin.

dung from sheep or cows contains calcium and sodium phosphates and is used as a fixing solution following alum mordanting. the dung is collected and dried before it is spoiled by rain, crushed, put shortly to boiling water, stirred and strained through a simple filter. this 'fixing solution' completes the chemic bond between alum and fibre and removes any excess minerals which would pollute the dyebath.

sheep dung

collecting cow patties