Gel Medium 4 oz. Jar. Gesso is an artist quality primer, ideal for preparing all types of surfaces. It provides a subtle texture for paint and mediums to grab and ensure smooth application. This opaque, quick-drying Gesso remains flexible after drying. Dina Wakley’s Gel Medium is a soft gel with a matte finish. Gel Medium is ideal for extending acrylic paints and can be used to dilute paint without breaking down the pigments. Dina Wakley’s Gel Medium can be used as a heavy duty adhesive, perfect for adhering collage and mixed-media ephemera. Other applications include resist techniques, glazing and can be used as a sealant.