Gesso Sottile Cakes

 The Art of making Gesso Sottile cakes; Stage One.

 

In this Art of making, we look at Gesso. Gesso is used as a base for canvas, linen or wood. I am explicitly talking about Gesso Sottile. Know and used by Cennino as “thin Gesso”.

What you will need.

  • Plaster of Paris
    Water
    Scales
    Bucket with lid (or similar)
    Stick or long wooden spoon for stirring
    Tray
    Airtight container
    Time
    Write the date you start making it on the bucket

Method.

Fill your bucket with one gallon of water.
Measure of one pound of Plaster of Paris (455 grams).
Sprinkle the Plaster of Paris over the water stirring as you add the Plaster.
IMPORTANT; Stir for 15 minutes continually. If this is not done, you risk the Plaster of Paris setting. If this happens, you will have to start again.
Stir every 15 minutes for two hours after the initial 15 minutes of stirring.
Cover the bucket to keep dust out.
Leave the mixture of Plaster of Paris and water for ONE MONTH.
Stir the mixture every day of the month (Thirty One days).

After the month is up, the mixture is ready.
Pour all the water out of the bucket, take care, and not lose the Plaster of Paris in the bottom.
Get the weighing scales. Weigh out 20g of the mixture (I just used my hands to get the mix out)
(NB. You can weigh the cakes out to whatever size you would like; however, I find 20g is a good size for making small batches of Gesso Sottile)
Form a mini cake with the Plaster of Paris and place it on a tray to dry out.
Continue this process till all the Plaster of Paris has been weighted and made into mini cakes.
Leave the mini Plaster of Paris cakes to dry out on the tray, around two days.
When they are dehydrated, pack into the airtight container.
These are now ready for you to use.

Congratulations on completing your first stage in making the Gesso Sottile.
The cakes are now ready to be added to rabbit hide glue or a gelatine solution to make the Gesso Sottile.

 

Have you had a go at making the Gesso? Show your work on Instagram and mention me in your post or story on @Gancarz.Art I would love to see your handcrafted Gesso Sottile.

 

Further Reading.

The Practise of Tempera Painting.  Materials and Methods. 1936 (Thompson, D.V) p37