USING CENNINI's GESSO /PREPERATION PROCESS
CHEMICALLY SOUND METHOD FOR PREPARING CENNINI's FORMULA FOR RAISED GILDING
TECHNIQUE OF RAISED GILDING BY JERRY TRESSER
fruitflies1@bellsouth.net   954 227 3967
Part 1   Part 2 (see below)

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                                       The Techniques of Raised Gilding an Addendum


Here is a synopsis of Part 1 & 2 of the formula from page 30 on the CD in a simplified form. Please don’t hesitate to contact me if you have any questions or are uncertain about any procedure.
JERRY TRESSER, fruitflies1@bellsouth.net or (954) 227-3967.

The Formula
8 Parts slaked plaster of Paris      
3 parts white lead                         
4 parts water                             
1 part sugar                                
1 part hide glue
Armenian Bole, pinch for color

Part 1   (GESSO SOTTILE)
8 parts slaked plaster
2 parts water                     
1 part hide glue
Armenian Bole, pinch for color

Part 2
3 parts white lead
*1 part sugar
2 parts water

Allow Part 1 to dry totally before adding Part 2 once dry, the foundation is set. Prepare the sugar water solution by dissolving one part sugar into two parts warm water. Then pour the sugar water solution into part one to soften it. You can add a little more water if necessary. I then add the white lead.

Once Part I & 2 have been mixed (I use a blender to mix) allow the whole mixture to dry. See the photo below. You have now completed the preparation process for Cennini’s recipe for Raised Gilding.

When preparing the mix I use a tablespoon as my measuring guide. The formula is based on volume, not weight. Therefore, if the ingredients call for 8 parts, its 8 tablespoons, and one part is equal to a tablespoon. The exception would be the Armenian bole as it’s used as a coloring agent. Only a small amount is needed to turn the mix a pink color which will make it easier to see when working with the gesso. Additional water can be added to either part 1 or 2 to help the chemicals dissolve more easily. In both parts the water will evaporate so it’s not a critical component in the preparation other than a vehicle for mixing.

Once Part 2 has dried the gesso can then be broken into pieces and stored in a glass container. It does not matter what shape the pieces are in (buttons, pie wedges, etc.). Once we are ready to reconstitute the gesso for use, I would strongly recommend breaking the gesso pieces up into a powder and weighing it with a gram scale prior to use.  I use a level 1/8 teaspoon of the gesso powder, weigh it and reconstitute the gesso with a known quantity of water by drop. I weigh & count the drops of water so
that I can duplicate the resulting mix. I suggest working with a small amount of gesso with a known weight for ease of handling.


                  













                           

                  


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Photo #  1 plastic Template for gesso, baster & glass bottle containing the gesso part I and 2 mixed .
Photo # 2 gesso poured into the button templates using the baister.
Photo # 3 once dried the gesso buttons are pushed out of the plastic template and kept for use at a later time . Store in a clean container.
Photo # 4 when ready for use the gesso buttons are ground into a powder, weighed and ready to be reconstituted. Once you set the weight, the mix can be duplicated with accuracy.
These photos were not in the original book published in 1992. We have added 10 additional pages in the CD . Jerry Tresser
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Part 2 in the application stage