Here is the formula: Purchase some ALUM (Aluminum Potassium Sulphate) Using a 1/2 teaspoon of the Alum, create a bath in a large tray , and soak the vellum in it for several hours. The amount of water in the bath should be enough to cover the skin that is going to be dyed. You can put some river rocks on each side of the vellum to prevent curling of the corners. This step does NOT have to be done if you are dying watercolor paper.
While the vellum is soaking, get a pot with a cover, and fill it with 40 oz of water. Add 4 oz. of the Brazilwood chips, and simmer for 3 hours. Avoid any boiling, you can simmer the water first for about a half an hour before adding the chips. The water will turn a deep burgundy. The more chips the deeper the color. But 4 oz seems to work well. In order to alter the color toward the blue, you can add some Logwood chips or Potash (Potassium carbonate (harmless) in very small quantities.
the Alum acts as a mordant which makes the dye attach itself to the vellum easier. Also, if you have to wait, take the soaked vellum out of the Alum bath and place it between 2 sheets of glass. Dont worry about its wetness. It will reamin flat, and moist.
I have used the outlined procedure below with very good results in dying vellum and 140lb CP Arches water color paper. Heavier weights of water color paper can also be used with excellent results.
Once the brew has cooled down, the liquid is placed in large jars for storage in my refrig. When ready for use. I use a large photo tray (which is shallow) pour the dye liquid into the tray and place the vellum or w.c. paper in it. Make sure the skin is completely covered with the dye liquid. To avoid curling, I use large river rocks on all 4 corners of the skin. After the vellum has fully absorbed the liquid, I take a sheet of glass larger than the tray and cover the top of the tray to avoid any evaporation. Sometimes it may be necesaary to add a little more brew into the tray. After 2 or 3 days the vellum is flipped over on the other side and allowed to soak for a few additional days. You can check the skin to see if the stain has covered the entire front and back The curling usually stops after the first day, because the skin is so oversaturated, The rocks are no longer needed. The skin stays submerged and the tray is covered again with the glass plate.
Both liquids can be saved. The Alum solution can be poured back into containers and stored for future use. The Dye liquid can be poured back and stored as well. You can also make a new batch with fresh chips and add it to the existing batch. Just keep it refrigerated. It will stay indefinitly.
I am sure their are many ways to stretch and dry the skin. Here is how I do it. The skin , once removed from the tray is placed on a sheet of glass, and a second sheet of glass is placed over it. I keep it this way until I am ready to stretch it. I may want to delay the use of the vellum. It stays moist and flat underneath the sheet of glass.
When I am ready to stretch it, I go to an art store and purchase 4 stretcher strips. I make a frame (which is easy because the strips are interlocking). I remove the skin from the glass plates and place it on the frame and staple (using an electric staple gun) each side down , The skin is tort, and dries easily (which usually takes about an hour or so. After it has dried, I place it back between 2 sheets of clean glass and it remains flat, and retains the beautiful color of deep burgandy . Its now ready for use.
PHOTOS WILL BE FORTHCOMING
