A thin clear varnish that goes on clear and stays clear. Usage A water soluble, self-levelling medium in either gloss, matt or satin that can be used to prepare surfaces. Gloss varnish can be used to prepare surfaces for decals and to improve the appearance of clear parts. Substrate Humbrol Enamel and Acrylic Paints. Application Shake well before use - some settlement may occur. Apply thinly with a brush or airbrush. To achieve a higher level of the desired finish, apply additional coats. Do not use in temperatures below 15ºC or in conditions of high humidity to avoid the appearance of a cloudy finish once dry. Drying Time Surface dry in 30 mins. Recoat once dry. Avoid temperature change during application and drying time. How to Clean Water.