Primer for the preparation of paints and colored plasters with very high penetrating ability that is diluted with water and offers an ideal substrate for colored, acrylic plasters and elastic coatings such as Kapalux, Monokapa, Granulato, and Plaster fin. It is suitable for porous substrates such as first coat plasters, concrete, bricks, aerated concrete, cementitious adhesive coatings, cement mortars, etc.