During the Renaissance period, which spanned from the 14th to the 17th century, the use of glues was widespread and played an important role in various artistic and craft activities. The most common types of glues used during this time were made from natural substances such as flour, cheese, animal hide, bones, and fish. These glues were commonly used in the production of paintings, sculptures, bookbinding, and woodworking.
The quality of the glue was crucial to the durability and longevity of the artworks, as well as their appearance. Therefore, artisans and craftsmen paid close attention to the preparation and application of these glues.
Flour-Paste Glue | Hide Glue | Fish Glue | Casein | Gum Arabic | Egg Glair
Flour-paste glue for paper
Materials & Tools
Flour-paste (also known as wheatpaste or flour-glue) is a simple adhesive made from wheat flour (or similar vegetable flours or starches) and water, often heated. It has been used since antiquity for paper-based arts and supports. When whole flour is used, the glueing action involves both starch and gluten proteins. Pure starch paste (without gluten) is more reversible, less prone for insect infestations and is widely preferred in conservation, printmaking and bookbinding today.
HOW YOU MAKE BATTER OR FLOUR PASTE. CHAPTER CV
The craftsman’s handbook by Cennini, Cennino, active 15th century; translated by Thompson, Daniel Varney, 1902- ed
[…] There is one size which is made of cooked batter, and it is good for paper workers and masters who make books; and it is good for pasting paper together, and also for fastening tin to paper. We sometimes need it for pasting up papers to make stencils. […]
Because of its reversibility, low acidity (when properly made), and compatibility with paper fibers, vegetal-paste is often the first choice among paper and book conservators. Its common uses include: adhering paper pieces, collage, chine-collé, mounting paper onto canvas or panels, papier-mâché, and sizing or priming supports.
As Vasari recounts in Lives of the Artists, artists in the Renaissance fastened together sheets of paper with flour-and-water paste, affixed them to walls (spreading the paste around the edges), damped them to stretch out creases, and then when dry used them for transferring designs (“cartoons”) to walls or panels:
§ 77. Sketches, Drawings, and Cartoons of different kinds.
The cartoons are made thus: sheets of paper, I mean square sheets, are fastened together with paste made of flour and water cooked on the fire. They are attached to the wall by this paste, which is spread two fingers’ breadth all round on the side next the wall, and are damped all over by sprinkling cold water on them. In this moist state they are stretched so that the creases are smoothed out in the drying.
Giorgio Vasari (1511-1574), Vasari on technique; being the introduction to the three arts of design, architecture, sculpture and painting, prefixed to the Lives of the most excellent painters, sculptors, and architects
Making the Wheat Flour Paste
Medieval and Renaissance recipes for this paste are often imprecise, likely because it was a common household material whose preparation was widely known and required little explanation.
HOW YOU MAKE BATTER OR FLOUR PASTE. CHAPTER CV
The craftsman’s handbook by Cennini, Cennino, active 15th century; translated by Thompson, Daniel Varney, 1902- ed
This size is made as follows. Take a pipkin almost full of clear water; get it quite hot. When it is about to boil, take some well-sifted flour; put it into the pipkin little by little, stirring constantly with a stick or a spoon. Let it boil, and do not get it too thick. Take it out; put it into a porringer. If you want to keep it from going bad, put in some salt; and so use it when you need it.
33. Cement for joining parchment is thus made
Manuscripts of Jean Le Bègue, 1368–1457, Mary P. Merrifield, Medieval and Renaissance treatises on the arts of painting : original texts with English translations
[…] But if you wish to join paper only and not parchment, wheat-flour or powdered bread-crumbs mixed with pure water and slightly boiled is very good for paper. But if you mix a little gum-arabic or whipped white of egg with it, it will do for parchment.
Chapter 52. Applying the Solder to Gold
Theophili, qui et Rugerus, presbyteri et monachi, libri III. De Diversis Artibus: seu, Diversarum artium schedulaWolfenbüttel, archive.org | Herzog-August Bibliothek cod. Guelph Gudianus, lat. 2°69, fol. 86r: incipit
[…] You should also have some fine flour of wheat or winter wheat, which you should mix with water in a small vessel and put on the fire to heat a little. Into this dip lightly the underside of each of the settings and so fix them firmly in place. […]
A cartoon for the fresco of the same name in Vatican is assembled from about 210 sheets used by Raphael that were glued to a support with flour paste.
The main steps to prepare the glue:
Ingredients:
- Distilled water (500ml)
- Flour (100gr)
- Additives (optional, see the list of additional ingredients)
Step 1: heat the water
It should almost boil
Step 2: Mix flour and warm water.
Proportions are nearly 1 to 5, but this was usually done by eye, depending on the desired density of the paste. You can sift the flour directly into the pot, or add sifted flour little by little.
Step 3: Condense it a little more
Continue heating gently and stirring until it gets quite dense.
Step 4: Add the additives if necessary
If you want to store it, add a preservative, if you want to change viscosity or adhesive properties you can add glycerin, gum, alum or whipped egg white (the last one would be better to add when the paste is already cold).
Additional ingredients:
- Preservative: Cennini suggest to use salt, but you can also try vinegar, wine or today you could use a chemically produced biocide such as Nipagina (Methylparaben), phenol or formaldehyde. If you do not intend to store the glue it is not necessary.
- Alum (Aluminum Ammonium Sulfate and Aluminum Potassium Sulfate), number of modern sources recommend adding alum as a hardener (around 1 teaspoon for 500ml of water will do).
To learn more about glues and adhesives used during the Renaissance and Middle ages, check out A Practical Guide to Medieval Adhesives by Maya Heath
Animal Skin Glue
Materials & Tools
Hide glue, also known as animal glue or rabbit skin glue, is general term for a range of adhesives made from animal collagen, usually from the hides of rabbits, cattle or horses. It has been used for centuries in painting, woodworking, musical instrument making, and bookbinding. Here are some key points about hide glue:
- Preparation: Hide glue is sold as a dry powder or in granular form. It is mixed with water to create a liquid glue that can be applied to surfaces.
- Application: Hide glue is applied while it is warm and liquid, usually with a brush. It sets quickly as it cools, so it is important to work efficiently. Some people prefer to keep the glue warm while working by using a glue pot or other heating device.
- Strength: Hide glue creates a very strong bond, but it is not waterproof. It is also susceptible to damage from high humidity or extreme temperatures. However, it can be easily repaired by reheating the glue and reapplying it. It is important to follow the instructions for mixing the glue, as too much or too little water can affect its strength.
- Shelf life: Dry powder or granular hide glue can be stored for extended periods if kept in a cool and dry place. However, once the hide glue is mixed with water, its shelf life is relatively short, and it can begin to spoil or become less effective after just a few days. To increase the shelf life of mixed hide glue, it’s recommended to prepare a strong glue mixture with a concentration of 20% or more and store it in the refrigerator. Additionally, preservatives can be added to the glue to extend its shelf life and prevent the growth of mold.
- Clean-up: Any spills or excess glue can be cleaned up with warm water while the glue is still wet. Once it has dried, it can be scraped or sanded away. It is important to keep tools and surfaces clean while working with hide glue, as it can be difficult to remove once it has dried.
Preparing the Hide Glue
CHAPTER XVI. HOW THE GREEN TINT IS MADE ON PAPER FOR DRAWING; AND THE WAY TO TEMPER IT.
Then temper the aforementioned substances with size of the following quality and strength: Get a leaf of druggists’ glue (not fish glue) and soak it in a pipkin for six hours in enough clear, clean water to fill two common goblets. After soaking, put the pipkin on the fire to temper it, and skim it when it boils. Once it has boiled and the glue is fully dissolved, strain it twice.
The craftsman’s handbook by Cennini, Cennino, active 15th century; translated by Thompson, Daniel Varney, 1902- ed
Recipe:
Preparing rabbit skin glue with a double boiler is a common method used by artists and craftsmen. Here are the steps involved:
Ingredients:
- 1 part glue (by volume)
- 4 parts distilled water (by volume)
Concentration (Strength):
To create different concentrations of glue, you can start with a 20% concentration and dilute it accordingly. For example, you can achieve a 10% concentration by diluting the 20% concentration by half, and a 5% concentration by diluting it by half again. If you need a 15% concentration, you can mix equal parts of the 20% and 10% concentrations etc. This allows for greater flexibility in creating the desired consistency for your specific project.
Preparation:
- Soak the rabbit skin glue in cold water overnight or at least for several hours until it softens.
- Transfer the glue and the water to a double boiler. If you don’t have a double boiler, you can use two pots or a heatproof bowl placed over a pot of simmering water.
- Gently heat the water in the bottom pot of the double boiler until it reaches a temperature between 120-140°F (49-60°C).
- Stir the glue mixture until it dissolves completely and becomes smooth.
- Once the glue is fully dissolved, remove it from the heat source. Never allow the glue to boil – overheating will compromise its adhesive properties.
- Use the glue while it is still warm and fluid, as it will start to gel and solidify as it cools.
It’s worth noting that some artists may add additional ingredients, such as vinegar or glycerin, to modify the properties of the rabbit skin glue. The exact ratios and ingredients used can vary depending on the artist’s preferences and intended use of the glue.
Additional ingredients:
- Salt: Adding a small amount of salt to hide glue can help to extend its shelf life by inhibiting the growth of microorganisms that can cause spoilage
- Glycerin: Adding glycerin to hide glue can improve its flexibility and reduce its brittleness, making it more durable and less likely to crack over time.
- Acetic acid: Adding acetic acid to hide glue can increase its water resistance and help to prevent the glue from becoming brittle over time. However, this should be done with caution, as too much acid can weaken the glue and cause it to fail.
- Preservative: Cennini suggest to use salt, but you can also try vinegar as a natural preservative. Nowadays, commonly used preservatives for hide glue include: phenol, formaldehyde, and sodium benzoate. Nipagina (Methylparaben) is also commonly used by Italian restorers. If you do not intend to store the glue, preservative is not necessary.
- Alum (Aluminum Ammonium Sulfate and Aluminum Potassium Sulfate), number of modern sources recommend adding alum (around 1 teaspoon for 500ml of water will do) that can improve tack and adhesion, making the glue more effective for difficult-to-glue surfaces.
Overall, hide glue is a versatile and reliable adhesive that has been used for centuries in various crafts and trades. It requires some care and attention during preparation and application, but it can create very strong bonds that are easily repairable.
Fish Glue
Materials & Tools
Fish glue has been used since antiquity and was already mentioned by Dioscorides nearly 2000 years ago under its Greek name Ichthyokolla. This glue was produced from bones and guts of big fish, but the highest quality variety, known as isinglass, was obtained from the swim bladder of the sturgeon. It is very transparent, delicate, very durable, resistant to water and has a longer drying time than hide glues. Painters employed it primarily for gold-leaf applications on ivory, stone and other surfaces, but it was also valued by luthiers and woodworkers.
385. To make fish-glue.
Secrets for Colors (Bolognese Manuscript), 1400-1425, Mary P. Merrifield, Medieval and Renaissance treatises on the arts of painting : original texts with English translations
Take the bones of a pike or of any other large fish, dry them, and reduce them to powder in a bronze mortar; then put the powder into a new pipkin, with as much water as you think sufficient for the bones or dust, and make the water boil until the bones are liquefied; then touch the water with your fingers, and if they stick together it is good and perfect. Then take it from the fire, and strain it through a linen cloth, let it cool, then cut it into pieces, and dry it in the wind without dust.
Chapter 28. Milling Gold for Books; and Casting the Mill
[…] Now take the bladder of the fish called sturgeon, wash it three
times in warm water, cut it up in pieces, put them into a very clean
pot with water, and let them soften overnight. On the next morning
cook them over the fire without letting them boil, and test with your fingers to see if they stick together. When they stick fast, the glue is good.Chapter 95. Carving Ivory
Theophili, qui et Rugerus, presbyteri et monachi, libri III. De Diversis Artibus: seu, Diversarum artium schedulaWolfenbüttel, archive.org | Herzog-August Bibliothek cod. Guelph Gudianus, lat. 2°69, fol. 86r: incipit
If you want to ornament your work with gold leaf, put an undercoat of glue from the bladder of the fish called the sturgeon, cut the leaf into pieces and lay them on as you wish.
IX. Of gold-leaf, how it is laid on ivory.
You will decorate carvings in ivory with gold-leaf. Now hear in what manner this thing is done. Seek to obtain the fish which is called “huso” [European sturegeon] and keep its air-bladder liquefied by being boiled in water, and with this mark over the place where you wish to lay the gold; and you will thus easily be able to fasten it to the ivory.318. To gild with gold leaf
Manuscripts of Jean Le Bègue, 1368–1457, Mary P. Merrifield, Medieval and Renaissance treatises on the arts of painting : original texts with English translations
Grind well some gypsum with pure clean water, dry it; then grind it with synople like rose, and with fish-glue dissolved in very good white wine, and with the pencil spread it where you please, covering well with it the part to be gilded. Then dry it, and make it smooth with the knife, apply the gold, fix it with the hematite and polish it, and if it does not succeed well, take the above-mentioned glue, spread it over the drawing, and over that the gold leaf.
HOW FISH GLUE IS USED, AND HOW IT IS TEMPERED. CHAPTER CVIII
The craftsman’s handbook by Cennini, Cennino, active 15th century; translated by Thompson, Daniel Varney, 1902- ed
There is a glue which is known as fish glue. This glue is made from various kinds of fish. If you put the little piece, or leaf, in your mouth, just as it is, until it gets a little wet, and rub it on sheep parchments or other parchments, this fastens them together very securely. To dissolve it, [you must put it on the fire] It is good and excellent for mending lutes and other fine paper, wooden, or bone objects. When you put it on the fire, put in half a goblet of clear water for each leaf.
Cennino does not describe its production process, but only its application, suggesting that it could already be purchased in shops during his time. Interestingly, in present-day Italy one still finds in supermarkets a product called colla di pesce (“fish glue”), a culinary gelatin sold as thin transparent sheets. Despite the name, this modern product is no longer derived from fish but from pork or bovine sources, yet it preserves both the form and the historical designation mentioned by Cennini.
Cheese (Casein) Glue
Materials & Tools
Casein glue is an adhesive derived from milk proteins, traditionally prepared by mixing well-seasoned and washed cheese with quicklime. This produced a strong, water-resistant glue widely used by woodworkers. In the context of painting, casein glue played an important role in the construction of wooden supports, particularly for joining the planks that formed panel paintings and altarpiece sections (scomparti).
Chapter 17. Panels for Altars and Doors; and Cheese Glue
The individual pieces for altar and door panels are first carefully fitted together with the shaping tool that is used by coopers and vatmakers. Then they should be stuck together with cheese glue, which is made in this way.
Theophili, qui et Rugerus, presbyteri et monachi, libri III. De Diversis Artibus: seu, Diversarum artium schedulaWolfenbüttel, archive.org | Herzog-August Bibliothek cod. Guelph Gudianus, lat. 2°69, fol. 86r: incipit
Cut soft cheese into small pieces and wash it with hot water in a mortar with a pestle, repeatedly pouring water over it until it comes out clear. Thin the cheese by hand and put it into cold water until it becomes hard. Then it should be rubbed into very small pieces on a smooth wooden board with another piece of wood, and put back into the mortar and pounded carefully with the pestle, and water mixed with quicklime should be added until it becomes as thick as lees. When panels have been glued together with this glue, they stick together so well when they are dry that they cannot be separated by dampness or by heat. Afterwards they should be smoothed with a planing tool [i.e., a drawknife] which is curved and sharp on the inside and has two handles so that it can be drawn with both hands.
Panels, doors, and shields are shaved with this until they become completely smooth. Then the panels should be covered with the raw hide of a horse or an ass or a cow which should have been soaked in water. As soon as the hairs have been scraped off, a little of the water should be wrung out and the hide while still damp laid on top of the panels with cheese glue.
TO MAKE A GLUE OUT OF LIME AND CHEESE. CHAPTER CXII
The craftsman’s handbook by Cennini, Cennino, active 15th century; translated by Thompson, Daniel Varney, 1902- ed
There is a glue used by workers in wood; this is made of cheese. After putting it to soak in water, work it over with a little quicklime, using a little board with both hands. Put it between the boards; it joins them and fastens them together well.
391. [To make cheese glue]
Secrets for Colors (Bolognese Manuscript), 1400-1425, Mary P. Merrifield, Medieval and Renaissance treatises on the arts of painting : original texts with English translations
Take cheese of any sort, tolerably old, and scrape it as thin as paper, or slice it very fine; and then take the scrapings and put them to soak in fresh water for a day. Strain off the water carefully, and then take warm water, as much or rather less than what you threw away, and put the scrapings into the warm water. Knead the whole well with your hands, just as dough is kneaded for bread, in the warm water until all the fat is extracted from the cheese. Continue changing the water, then make the cheese into a cake, and put it into a vase of fresh water, so that it may always be covered with water. And when you wish to use it, take whatever quantity you want of the cake, and mix it with a little quicklime upon a very smooth board, kneading it well with a wooden stick ; then add to it a little sifted gesso, and mix the whole up again for a considerable time, and it will become cheese-glue for cementing wood-work and vases, and it must be used as fresh as possible, because then it takes a better hold.
Casein Tempera:
Colors utilizing milk protein as a binding agent represent one of humanity’s oldest painting media, with archaeological evidence spanning 50,000 years and continued contemporary relevance.
The chemistry involves combining alkaline materials like borax or lime with casein, transforming the milk protein into a powerful adhesive binder that effectively suspends pigments. This fully natural medium provides excellent adhesion to porous surfaces, dries rapidly, and allows easy cleanup while wet.
Casein tempera excels for wall painting due to its compatibility with masonry and natural breathability. It offers versatile working properties from watercolor transparency to oil-paint opacity, making it valuable for both historical restoration and contemporary sustainable art practices.
Gum Arabic
Materials & Tools
Gum arabic is a natural tree exudate harvested from acacia trees (Acacia senegal and Acacia seyal), primarily from North Africa and the Arabian Peninsula. There are over a hundred different species of acacia that produce gum, but Acacia Verek better known as Acacia Senegal is especially prized. These trees must be 6-30 years old to produce quality gum. When dissolved in water, it forms a clear, pale solution that acts as an excellent binder for pigments or as a glue. The gum is composed of complex polysaccharides that create a flexible, water-soluble film when dry.
CHAPTER XVII. On gum arabic water.
Take white and clear gum arabic, break it into small crumbs or grind it, put it in a glazed vessel and pour over it enough common water to cover it by two fingers. Leave it for a day and a night, then place it for some time on hot ashes until it dissolves; and just as you already tasted the glue water, taste this too to see if it is of good tempera and neither too strong nor too sweet; then, having strained it through a small cloth, keep it in a bottle and use it.
De arte illuminandi (Libellus ad faciendum colores), 14th century, in Sui colori degli antichi, Introduzione, parte prima : Dalla remota antichità al secolo 14. ; De arte illuminandi by Guareschi, Icilio
Properties and Functions
Technical characteristics:
- Colloid-protective agent: Acts as an excellent protective colloid
- Emulsion stabilizer: Frequently used to stabilize emulsions or dispersions and as a thickening agent
- Water-soluble binder: Used in aqueous solution as a binder for watercolors and gouaches
- Adhesive properties: Serves as adhesive for paper and cardboard, and is commonly employed as sizing for envelope flaps and stamp adhesives
- Ink component: A fundamental component in the manufacture of writing inks, mixed with pigments
Medieval and Renaissance Applications
- Manuscript illumination: The principal binder for pigments used in illuminated manuscripts
- Tempera painting: Mixed with egg or used alone to bind colors on parchment and paper
- Gold and silver adhesive: Used to adhere gold leaf to manuscript pages
- Drawing and writing: Prepared colored inks and washes for drawing on paper, essential component of iron gall inks
Egg Glair
Materials & Tools
Glair (from the late Latin clarea, meaning “clear”) is the settled liquid obtained from egg white foam, used extensively as a binding medium in medieval and Renaissance manuscript illumination and panel painting. Unlike whole egg tempera, glair consists primarily of water (approximately 88%) and denatured proteins, creating a transparent, free-flowing medium ideal for delicate work on parchment. The preparation of glair was a delicate process requiring skill and attention—any failure could result in loss of adhesive power. Three methods existed for preparing glair: whipping with a wooden whisk, pressing with a sponge, and filtering through linen cloth. Each method aimed to denature the proteins completely, transforming the egg white into a workable binding medium. Interestingly, aged glair (three to four days old, even slightly putrefied) was often preferred over fresh, as it provided better shine and strength to pigments.
HOW TO GILD GLASS FOR RELIQUARY ORNAMENTS.
Then take the white of a fresh egg; beat it with a good clean whisk just as you do that for gilding, so that it is thoroughly beaten; and let it distil overnight.
The craftsman’s handbook by Cennini, Cennino, active 15th century; translated by Thompson, Daniel Varney, 1902- ed
CHAPTER XVI. On egg white and how it is prepared.
Chicken egg white, which is the best, is prepared thus: take fresh eggs, one, two or more, according to need; break them carefully, extract the white separating the chalaza without mixing in the yolk; put in a glazed bowl and with a fresh sea sponge because it is better, if you have it, and if you don’t have it, since there is not abundance of it, provided it is well washed, work it for a long time with your hands until all the white is absorbed by it. The sponge must be of such size as to be able to absorb all the aforementioned quantity of white that you have taken. Then finally squeeze it into the said bowl and take up again with the sponge until it no longer makes foam and runs like water; and then use it. If you want it to keep for a long time without stench and without putrefying, put in a glass bottle, together with the white, a little red realgar, in the quantity of one or two beans at most, or a little camphor or two clove buds, and it will keep. When you want to use it to fix gold, break it up with a bristle brush or a split reed, as was said above.
De arte illuminandi (Libellus ad faciendum colores), 14th century, in Sui colori degli antichi, Introduzione, parte prima : Dalla remota antichità al secolo 14. ; De arte illuminandi by Guareschi, Icilio
XXXI. [284] Of the manner of preparing white of egg for tempering colours.
Manuscripts of Jean Le Bègue, 1368–1457, Mary P. Merrifield, Medieval and Renaissance treatises on the arts of painting : original texts with English translations
When you are going to prepare white of egg, take a filter, and dip it in water, and wet it well, and afterwards receive the white of egg mixed with water in this filter, which must be folded up so as to be pointed at the bottom and open at the top; and so, squeezing it, make it pass through seven or eight times, or oftener or less frequently, if necessary, for you must do this until the white of egg becomes like water, and runs through without drawing into threads. Then take it and put it by; or, if you wish, write with it. Two vases are necessary for preparing it.
Properties and Functions
Technical characteristics:
- Primary composition: 88% water with denatured proteins containing hydrophilic and hydrophobic amino acids
- Transparency: Creates a clear, non-yellowing film when dry
- Fluidity: Free-flowing medium, excellent for pen work and detailed brush application
- Aging improvement: Old glair (3-4 days) often superior to fresh, providing varnish-like brilliance
Medieval and Renaissance Applications
- Manuscript illumination: Principal binding medium for pigments on parchment
- Gilding adhesive: Used to fix gold and silver leaf (mixed with water or used neat) in water gilding process.
- Panel painting: Occasional use in tempera painting
- Varnish: temporary varnish on panels, or with addition of honey water as permanent warnish on parchment.