To ensure his image was as accurate as possible, Maclise undertook extensive research into uniforms, weapons and portraits. His sketches, and those that were sent to him by others including Prince Albert, survive in a large sketchbook.
Before starting to paint, Maclise produced a full-size preparatory drawing known as a cartoon, which was widely praised for its beautiful draughtsmanship and fine detail. But when he came to transfer the image to the walls of the Royal Gallery he ran into trouble.
At the FAC's insistence, Maclise began by painting in fresco (using 'fresh' or wet plaster), a rigorous technique that limited his ability to paint the level of detail needed for 'Waterloo'.
To solve this problem, Prince Albert sent Maclise to Germany to learn a newly invented technique, which involved applying pigments to dry plaster and fixing with ‘waterglass’ (potassium silicate). Armed with this knowledge, Maclise completed the vast painting in under two years.