Everything you need to know about soft pastels
In principle, any surface can be used, provided it has sufficient surface structure. Paper is usually used. In pastel painting, dry coloured powder is transferred from the pastel onto the paper. Unlike paint, pastel does not have the property of adhering to the surface through a binding agent. The pastel powder sticks to the fibres of the paper, as it were. To be able to apply a lot of colour, the paper must therefore have a certain surface structure. Drawing paper that is suitable for Siberian chalk, for instance, is too smooth and/or too hard to hold enough pastel. When using other flexible substrates such as textiles, it is important that the painting is framed so that the substrate cannot move. Vibrations can cause the pastel particles to come loose.
One of the specific characteristics of a pastel painting is its velvety appearance. Fixing the painting will change this appearance, depending on the amount of fixative. If too much fixative is applied, the colours darken from one moment to the next and even then the painting is not smudge-proof. For the sake of specific appearance, there are painters who do not fixate their work at all and therefore accept vulnerability. A safe way is to lightly fixate each layer of applied pastel in between with Talens concentrated fixative 064. Depending on requirements, the last layer can either not be fixed or also lightly fixed. There are also painters who do varnish their work heavily, taking into account the darkening of the colours. This, of course, requires experience.
Pastels cannot be framed directly against the glass. A passe-partout is needed to protect the work. Read more about "Framing pastels" here.
All Rembrandt soft pastels are acid-free.