Some years ago I attended a workshop with Timothy Noad, an English calligrapher/illuminator who is an expert in raised gesso gilding techniques. I then made this application in my sketchbook: a nearly-square shape with alternating parts in gold leaf and gouache. You can see on the photo that some of the square blocks have been raised. At these places the gold has been applied onto gesso. Gesso is a mixture of slaked plaster, white lead, sugar and fish glue. This is a a labor-intensive work that I'm not going to explain here but you can easily find information on the internet. In the middle I put the word 'or'. The gold on the background is not laid on gesso but on a base of flat mixion. Afterwards I have pricked holes in it.
"Kalligrafie & Ornament" / Timothy Noad & Patricia Seligman
In the following book you can find the recipe of the gesso, but also a lot of information and examples of different writing styles and illumination techniques:
"The Art of Illuminated Letters" / Timothy Noad & Patricia Seligman