Gesso's formula consists of different materials. Some gesso contains glue, plaster, and zinc. Other types of gesso are created from mineral calcium, acrylic latex, and chemicals that allow the gesso to be painted over. While gesso reacts the same when dry, how it is formulated seems to depend on the manufacturer.
Black gesso has often been compared to thick syrup. Unlike white gesso's consistencies, which are typically thin, black gesso is very thick and often needs to be thinned down with water. Liquitex flow improver is also a good choice for thinning down black gesso that is too thick to manage.
Many mixed media artists use black gesso in their art journals, altered book projects and mixed media paintings. Because the black gesso takes so well to white ink and white acrylic paint, it is possible to create very dramatic pieces of art in comparison to using standard acrylic black paints.
Usually one coat of gesso is enough when working on art projects. However, if artists are using black gesso in book arts, they may choose to use more than one coat to create a sturdier page. This is all based on preference. If you choose to use more than one coat of gesso, it is important to allow the first coat to dry completely before applying the next.
Black gesso is easy to use, but it can be very messy. If you are the type of artist that likes to apply the gesso and start working with it before it dries completely, you will create more of a mess. Cover your work surface with newspapers or cardboard, and wear plastic gloves to prevent staining on your hands. Either or sponge brush or a standard bristle brush can be used to apply black gesso. Rinse brushes immediately after use.
You will find black gesso is more expensive than white. When making your selections, choose the highest quality black gesso you can find. If you buy a low quality black gesso to save money, you will see a notable difference in your art piece. Lower-grade black gesso is fine for practicing, but finished pieces should really be completed with a higher-grade.
Some black gesso comes very thick and, when dry, can be sanded down. This is very useful for book artists looking for a sturdy medium to use on book covers. This heavier thickness, however, is more difficult to work with on the book's interior pages. You will need to thin it down considerably, or use a thinner type of black gesso.