Gouache tubes and a "Chinese white" tube was added to boxes for this purpose. Later that century, for decorative uses "poster paint" was mass-produced, based on the much cheaper dextrin binder. It was sold in cans or as a powder to be mixed with water. The dextrin replaced older paint types based on hide glue or size. During the twentieth century, gouache began to be specially manufactured in tubes for more refined artistic purposes. Initially, gum arabic was used as a binder but soon cheaper brands were based on dextrin, as is most paint for children. A relatively new variation in
Hand-colouring of photographs finish. Before the paint can be applied, the surface of the print must be primed so that the colours are not repelled. This often includes prepping the print with a thin coating of shellac, then adding grit before colouring. Watercolour paint used in photographic hand-colouring consists of four ingredients: pigments (natural or synthetic), a binder (traditionally arabic gum), additives to improve plasticity (such as glycerine), and a solvent to dilute the paint (i.e. water) that evaporates when the paint dries. The paint is typically applied to prints using a soft brush. Watercolours often "leave a darker edge of color at