Art Spectrum Colourfix Primers allows you to work in several layers with little to no fixing and allows the use of wet media such as oils, watercolor and acrylics colors for mixed media works. Colourfix primer is avaiable separetely and is the same used for priming the sheets. Use them to prime any paper or board or to cover unwanted passages or to "touch up" smudges or for reverse painting effects. Primers may be mixed to create unique hues. Clear primer makes virtually any surface, even glass, a pastel surface and is excellent for experimenting allowing you to add pastels into your watercolors, acrylics or oil colors.