Aluminium potassium sulphate (or 'alum') is a mordant used to treat paper prior to marbling. This ingredient is key for making the paint stick!
Mix 10.5g alum with 120 mL freshly boiled water and use a paintbrush or sponge to coat the paper you wish to marble. Apply 15-20 minutes before marbling for best results. You don't need your paper to be completely dry to marble it.
You might also be interested in these items
Beginner's Complete Marbling Kit
Sign up for our newsletter
Sign up for our mailing list to receive new product alerts, special offers, and coupon codes.