On traditional gesso (gesso sottile)

So I’ve been preparing some panels with traditional gesso and due to the lack of credible information I’ve found on the internet I’ve decided to provide you, dear readers, with all the information I have on the preparation of panels in the traditional method.

As I see it, traditional gesso has some significant advantages over acrylic gesso:

a) an amazingly smooth surface

b) a more absorbent surface

c) an almost luminous quality

…the only drawback as far as I can see is that it is more brittle than acrylic gesso and as such it could potentially crack if it were to experience too much atmospheric change (especially if the panel is not properly sealed). This also means that it is unsuited for use on canvas (however, I did read that by using thin layers of gesso separated by thin layers of rabbit skin glue has been used to create pieces that can actually be rolled.

So, my method for doing this was taught to me by Greg Porcaro and supplemented with some independent research:

Ingredients:

1 part prepared rabbit skin glue (I’m using Gamblin brand, Greg used Daniel Smith brand)

1 part calcium carbonate (AKA marble dust AKA whiting) (I once read that sea shells were originally ground up for this purpose)

1/5 part titanium dioxide (this is an approximation, it just there to make the mixture more pure white. I just add a few dashes for each cup of calcium carbonate)

Method:

1) Mix rabbit skin glue according to package (mine involves soaking 3 tblsp. in 1 quart of water overnight and then slowly heating in a double boiler* until the gelled glue dissolves. Boiling or freezing the rabbit skin glue is bad-the point of the double boiler is to heat the solution evenly so the glue retains it’s stickiness). You will have to maintain the glue at a warm temperature throughout the process (I start to get mine up to temperature at the 2 setting on my stove but then lower it down to the lowest setting to maintain it).

2) Use the rabbit skin glue to seal the panel (I use birch plywood for my panel, by the way, with 1″x3″ #1 select pine boards for sides and braces). Do at least two coats, waiting for the glue to dry in between coats. Seal the sides as well as the front and back.

3) Mix the titanium dioxide into the calcium carbonate.

4) Slowly sift titanium dioxide/calcium carbonate mixture into rabbit skin glue and stir.

5) Apply to the panel evenly. The gesso will start drying fairly quickly once you start putting it on and you don’t want to go back over the partially dried parts (your brush will cause the partially dried gesso to clump). You will need to put on at least 7 layers (make sure each layer is completely dry before you put on another layer-the best way to check this is to feel if it is still cold-if it is…wait).

6) Sand surface. Start with a 80 or 100 grit sand paper and then use a superfine grit to finish. I do this by hand and it goes fairly quickly (you probably could use an orbital sander but the surface comes off pretty quickly so you could easily overdo it).

7) Some people put on a final layer of rabbit skin glue to impede absorption but I do not.

8 )Paint.

That’s it-easy and cheap and beautiful.

*You can easily make a double boiler by getting a medium sized pot and a metal container (another pot or a mixing bowl) that fits just inside the pot and using marbles to separate the two.