Ferrous sulphate is a mordant and a modifier. Known since ancient times as copperas and as green vitriol. It will improve wash- and light fastness on any fabric. Use in low percentages so not to damage the fibres, more than 2%WOF can make protein fibres brittle.
 
Ferrous Sulphate is called 'the sad mordant' because it tends to darken the colours. Use with weld for moss greens, with cochineal for dark purples, and with madder for burgundy reds.
 
Ferrous Sulphate will create blacks and grays when used with Black Tannin.
 
It is recommended to have a look at the different dye instruction modules available here.
 
Pay attention; this is Ferrous Sulfate Heptahydrate with a purity of 99%, not the stuff you can get in the regular shops, which makes it more expensive but in my opinion; worth it.
 
-Securely packed in a re-sealable zip bag for easy use and storage
-Comes with dye recipe.
 
View safety data sheet here