The watercolour monotype process is complex and lengthy. It involves applying water colour paint and/or water colour crayon in layers to a sanded Plexiglass printing plate. Each layer of colour must be dry before subsequent layers are added. On average, at least 8 layers of colour are applied to a printing plate before it can be printed.

The paint can be applied to the Plexiglass plate in many ways. The most common methods of paint application are by brush, splattering, or applying it directly from the tube and then manipulating it with various plastic scrapers. Objects such as feathers, string or netting are sometimes added to the plates to help create an image. Sometimes decorative papers are added during the printing process to produce a print with collage features. This type of print is called “Chine-Collé.” Additionally, stencils can be made from mat board and used during printing to produce embossed prints.

Once the plate it ready, damp printing paper is placed on it, and the plate and paper are run through the press. The press consists of two rollers (similar to an old-style wringer washer) with a metal sheet, called the press bed, which moves between the rollers. Specialized felt blankets are placed between the paper, which is resting on the printing plate, and the rollers. As the plate and paper pass between the rollers, the moisture in the paper reactivates the paint and several layers of the paint adhere to the paper. Unlike conventional print making, not all the medium is removed from the plate, which allows several prints to be made from one plate.

Once the plate and paper have gone through the press, the paper is carefully peeled off the plate to reveal the image. Each print will be different from the preceding one depending on how much paint is transferred to each new piece of paper. The differences can be subtle or striking. Once the print is dry, the artist sometimes adds to it through the application of paint or collage elements, or by drawing into it.

Because no print produced using this method can be accurately recreated, prints using this method are considered monotypes, and as such each is an original. Unlike an etching, where the artist endeavours to produce a series of identical images from one plate, monotypes are truly one-of-a-kind.