Ottosson Zinc Additive is a concentrated form of zinc and recommended for Linseed Oil Paint that is not already formulated with zinc, a natural fungicide that creates a slightly harder painted finish.
 
For Allback Linseed Oil Paint that is not formulated with zinc, add 5-10% of the Ottosson Zinc Additive to dark colors and 10% of the Ottosson Zinc Additive to light paint colors. 
 
Mix very well and mix with care as too much zinc can create a brittle Linseed Oil Paint - too little and it will not be effective.
 
Ottosson Linseed Oil Paint and Viking Linseed Oil Paint are both already formulated with zinc.
No additional zinc should be added.