Many of Jo Nin's works are based on gouache, watercolour chalk, chinese ink and pastel. Over the past decades, however, Jo Nin has repeatedly refined a special painting technique, the monotype. In this technique he mainly uses his nude sketches, which he previously sketched with watercolour pencil, graphite pencil or ink brush.
The monotype is a painting technique of the fine arts invented by Giovanni Benedetto Castiglione, who came from Genoa, in the 17th century. The monotype is a combined process in which first an oil paint of the desired shade and ideal viscosity is mixed and applied to a metal plate. Then the laterally reversed drawing, painting and pressing process takes place from the back of the base material, for example on paper or cardboard, which creates the work of art on the front.
The monotype ("a single image") is an original, it is not possible to produce a second identical image as would be possible with a conventional print.
Jo Nin uses highly viscous and translucent oil paints and mixes them herself. If the colour tone and viscosity are correct, the paint is applied to the metal plate with a spatula and rolled out as evenly as possible with a rubber roller. He then lays the painting ground on the coloured plate. Jo Nin uses either letterpress paper with a rough surface or a light cardboard as a painting base. Then he paints the actual motif of the painting. The pressure exerted on the painting tool, such as graphite pencil or paste crayon, creates the final motif in oil paint on the back of the painting ground. Sharp lines are painted with a fine or blunt graphite pencil, while soft gradients are created by pressing gently over the surface with the ball of the hand or textile. The painting is signed either laterally reversed during the painting process, or afterwards laterally correct on the front.
Multi-coloured monotypes are created by repeated painting and pressing processes on differently coloured metal plates. In this case, the additional colour mixture of the translucent oil colours, which add up in colour, must be taken into account.
The general difficulty is that Jo Nin only sees his painted lines and areas in the original when the work is finished and he picks up the painting ground from the last metal plate. The viscosity of the oil paint, the surface structure of the cardboard or paper and the type of drawing itself have a decisive influence. They lead to unique pictures - in the truest sense of the word, because they are unique.