Often artists will create a drawing or sketch on paper, and then want to adhere it to a stretched canvas to create a stronger support, or continue adding subsequent layers of paint. Here below is a method I learned from painter/instructor David True, who taught a workshop I attended years ago at Anderson Ranch.
Start with a canvas that is stretched and primed with gesso so it isn’t too absorbent. It should be the same size as the paper drawing, and the paper drawing should have extra border room so about 1/2″ of its edges all around can be chopped off later. Apply a new layer of gesso (not diluted with water) onto the canvas. While the gesso is still wet place the paper over it. Put a piece of tissue or clean sheet of paper over the drawing so you can smooth it out without smearing the drawing. Using your hands smooth the paper into the wet gesso starting from the center and moving outwards towards the edges. The paper will stretch as it gets wet from the gesso, and will move over the edges, so you end up losing about 1/2″ of the drawing along the borders. When it is all smooth, let it dry. After it’s dry you can easily trim the excess paper by running a single edge blade along the outside edges. This technique gives a very clean edge so you can’t tell the paper has been glued.
Extra Tips: place masonite or something under the canvas to prop it up and give it some stability so that when you rub the paper to smooth it out it won’t sink down in the center with the canvas. Another tip: the most important thing is that the gesso is still wet everywhere when you put the paper drawing over it. If the gesso dries in spots you will get wrinkles there. When you are working with a large size, or in a dry or hot climate, and you have difficulty doing this technique keeping the gesso wet, you can first apply a gloss medium or gel to the primed canvas. When the gloss layer dries, the surface is less absorbent, and then when the gesso is applied it will stay wet longer.