Cadmium Yellow

One more reason why it is important to know what products you are using! In 2010, the Office for Science and Society, separating Sense from Nonsense write an online article concerning a Cadmium Yellow Pigment Scare.

Cadmium was discovered in 1817 by Professor Friedrich Strohmeyer in Germany while looking into a problem encountered by apothecaries who were making calamine lotion for skin care. The process involved heating “calamine,” a natural ore of zinc carbonate, to produce zinc oxide, which is the active ingredient in calamine lotion. Sometimes the lotion would end up with a yellow discoloration which Strohmeyer determined was due to a mineral contaminant that he eventually identified as a compound of cadmium. Cadmium sulfide was prepared with an acid solution of cadmium salt (either chloride or sulfate) which was heated with hydrogen sulfide gas until a powder was formed. Hues ranging from lemon yellow to a deep orange were made this way.

It was this color of cadmium compounds that led to their first commercial use. Artists loved the bright yellow of cadmium sulphide and the reds and oranges resulting from a mixture of cadmium sulphide and cadmium selenide. Unfortunately, with time, cadmium sulphide oxidizes to cadmium sulphate, which is white, resulting in the original color of the painting being slowly altered. Claude Monet‘s famous yellow hues were also achieved with cadmium pigments.

Cadmium paints are still used today, although they are being phased out. Indeed, Sweden has submitted a report to the European Chemical Agency claiming that artists rinsing their brushes in the sink are responsible for spreading cadmium over agricultural land via sewage sludge.

Cadmium is a cumulative toxin and the World Health Organization has suggested 70 micrograms as the maximum daily safe intake. Ingesting some cadmium is unavoidable because it shows up in crops. How does it get there? Sewage sludge and phosphate rock, both used as fertilizer, can harbor cadmium. As a result, a hamburger can contain about 30 micrograms of cadmium that can be traced to the grass or hay the cow ate, and ultimately to the soil in which the feed was grown. Coal also contains cadmium compounds that can end up in the atmosphere from where they find their way into soil via rain. Other cadmium compounds may also be released from the nickel-cadmium battery industry, although modern pollution control methods minimize such losses. Cadmium can be also be found in significant amounts as a contaminant in zinc ores and some is released into the environment when the ore is mined as well as when it is smelted into zinc.

A modern example of when NOT to use Cadmium Yellow in merchandise: As a cross promotional feature, the company introduced a set of glasses decorated with images of Shrek and other characters from the film. After millions of the glasses had been sold, a problem cropped up that led to a large-scale recall. The yellow pigment used on the cups turned out to be cadmium sulphide, a substance toxic even in small amounts. The concern was that the pigment might rub off on children’s hands and end up being ingested if they then put their hands into their mouth. Nobody actually carried out a study to determine how much cadmium pigment can rub off onto little hands when gripping a Shrek glass, but it could well be less than what is found in the hamburger those hands are clutching.

Shrek glasses are not the only items aimed at children that have caused a concern about cadmium. With lead being non-grata, cadmium has been turning up in jewelry aimed at young girls, mostly originating in China. If pieces are accidentally swallowed, or if the jewelry comes into frequent contact with the mouth, enough cadmium may enter the circulation to cause harm. Jewelry made with cadmium should to go the way of the Shrek glasses. Eliminating any avoidable source of cadmium is desirable, especially since there is suspicion that cadmium compounds may be carcinogenic. Cadmium can also build up in joints and the spine causing a disease that the Japanese have named “Itai-Itai,” which translates as “ouch-ouch,” due to the painful sounds made by victims as cadmium accumulates.

A classic case of environmental cadmium toxicity can be traced back to the early 1900s, although its cause was not identified until the 1960s. It was obvious that something was going on in the vicinity of the Jinzu River and its tributaries in China. People were getting sick, screaming in pain and dying prematurely. Suspicion fell on the river and the mining companies that for years and years had been disgorging their wastes into the water. The mountains upstream were rich in minerals that contained silver, lead, copper and zinc, and mines had been operating there for centuries. As demand for these metals increased in the twentieth century, more and more mining wastes found their way into the river, including increased amounts of cadmium ores.

River water was used for irrigation of rice fields, and since rice absorbs cadmium effectively, the metal accumulated in the food supply and consequently in the bodies of the population. The result was ouch-ouch disease. Although cadmium was only identified as the cause around 1965, by the late 1940s it had become obvious that the disease was linked to the water supply and mining companies began to store their wastes instead of releasing them into the river. This prevented more people from contracting cadmium poisoning, but nobody really knows how many victims the mining operations had since they began to pollute the Jinzu River back in the sixteenth century.

In 1966 in England a construction worker died and several others were sickened as a result of inhaling cadmium fumes. The men were using a welding torch to remove bolts as they were dismantling a construction tower used in the building of a bridge. It is common practice to electroplate steel bolts with cadmium, particularly those exposed to water. This is especially useful when there is contact with sea water since cadmium reacts with salt to form an impervious layer of cadmium chloride. In this case the men inhaled the cadmium vaporized by the heat of the welding torch and suffered an acute reaction.

These are just a few examples of why we need to be aware as painters of what we use, the consequences of inhaling airborne particles, and why we should avoid getting some paints on our hands.  Just because it is water-based and easy to purchase from a store, doesn’t mean that it is a safe product.

Much of the information above can be found in it’s original format: Yellow






Dye Vats in Morocco

I mentioned Fez (also spelled as Fès or Fes) Morocco yesterday in the post on Madder Lake. Unfamiliar with Moroccan tanneries, the color vats intrigued me. Here is an interesting side note and some visuals on the tanning of leather that uses an 11th century technique that is still in use today. Barbara Weibel posted a nice article and photos on tanneries in 2013. Here is the actual link for much of the information below:

Many of the images available online depict the Chouara Tannery. Various article note that is the largest of the three tanneries in Fez, Morocco. Built in the 11th century, leather goods have been produced there using the exact same method for more than a thousand years.

The dying process: skins are first placed into the white vats, which contain a mixture of water, limestone, and pigeon droppings. The limestone helps to remove hair from the skins while the acid in the pigeon droppings softens the hides. Three days later the skins are removed and washed, after which they are placed in the dying pits.

Dye colors are all derived from natural products: red from the poppy flower, orange from henna, blue from indigo, and yellow from saffron, but because saffron is so expensive yellows are produced by hand-rubbing a small amount of the spice mixed with oil into the hides. The colors in the dye pits vary from day to day.

Men in skimpy shorts, many with bare feet and legs, stand thigh-high in the dye solutions to agitate the hides. They basically function as human washing machines. Camel, sheep, cow, and goat hides are placed in the dye vats. Then, the skins are pulled out of the pits once the desired colors are achieved, then trimmed and laid out to dry on in the sun. Next, they dry hides are moved inside for cutting and sewing. Often design and color will appear the same, but the feel may be very different due to the type of skin used for production. Touch will identify whether they had been made from camel, sheep, cow, or goat hides.

What I find interesting is the used of pigeon droppings. I believed that this particular type of bird excrement is considered toxic waste in the United States and needs men in haz mat suits to remove it from roof tops when either restoring or repairing some buildings. If I am not mistaken, this was a problem when repairing the Minneapolis Scottish Rite roof years ago. It would be interesting to see the repercussions of handling pigeon droppings and what the average life expectancy of a tannery worker is today, versus in the 11th century.

Here is the official word from one business selling a product called Germ Clear Bird Droppings Cleaner: “Although some commercial contractors will offer the client cleaning works on the basis that guano can be a health hazard, in reality cleaning is for aesthetic and practical reasons rather than to control disease. Much is made of the potential to contract a disease from contact with pigeon droppings, but this is often over exaggerated and the likelihood of a human being contracting a disease from contact with pigeons or their excrement is very low and certainly no higher than having contact with your cat. In the main it is the media that have perpetuated this hype for profit. The media needs to sell newspapers and the pest control industry needs to sell its services. In both cases the public is sometimes misled. Most experts are of the opinion that human contact with pigeons and/or their excrement is no more harmful than contact with a caged bird or any other family pet. The only way in which pigeon guano can usually have a detrimental effect on human health is where an individual who has a pre-existing respiratory condition comes into contact with very well dried guano. In these cases it is possible that the inhalation of dust, created when well-dried guano are disturbed, may irritate the bronchial passages. In almost every situation “dampening down” the droppings with water before the commencement of cleaning will prevent the creation of dust.” Here’s the link

I wonder if the individual picking up pigeon droppings is wearing gloves and a mask.














Madder Lake


As posted yesterday: a lake pigment is a pigment manufactured by precipitating (creating a solid from a solution) a dye with an inert binder or mordant, usually a metallic salt. Unlike vermillion or ultramarine and other pigments made from ground minerals, lake pigments are organic. Manufacturers and suppliers to artists and industry frequently omit the lake designation in the name. Many lake pigments are fugitive because the dyes involved are unstable when exposed to light. Red lakes were particularly important in Renaissance and Baroque paintings; they were often used as translucent glazes to portray the colors of rich fabrics and draperies.

I decided to delve into Madder Lake and Lake Pigments.

The production of a lake pigment from madder seems to have been first invented by the ancient Egyptians. Several techniques and recipes developed over time. The ideal color was said to come from plants 18 to 28 months old that had been grown in calcareous soil , or soil that is full of lime and typically chalky. Most lake pigments were considered relatively weak and extremely fugitive until 1804, when the English dye maker George Field (1777?-1854) refined the technique of making a lake from madder by treating it with alum and an alkali!  The resulting madder lake had a less fugitive color and could be used more efficaciously, for example by blending it into a paint. Over the following years, other metal salts, including those containing chromium, iron, and tin were found to be usable in place of alum to give madder-based pigments of various other colors.

In 1827, the French chemist Pierre Robiquet (1780-1840) began producing garancine, the concentrated version of natural madder. He then found that madder lake contained two colorants, the red alizarin and the more rapidly fading purpurin (mentioned in yesterday’s blog). Again, purpurin is only present in the natural form of madder and gives a distinctive orange/red generally warmer tone that pure synthetic alizarin does not. Purpurin fluoresces yellow to red under ultraviolet light, while synthetic alizarin slightly shows blue or violet under ultraviolet lights. Alizarin was discovered before purpurin too, by heating the ground madder with acid and potash. A yellow vapor crystallized into bright red needles: alizarin. This alizarin concentrate comprises only 1% of the madder root.

As noted in yesterday’s post, natural rose madder supplied half the world with red, until 1868, when its alizarin component became the first natural dye to be synthetically duplicated by Carl Gräbe (1841-1927) and Carl Liebermann (1842-1914). However, their recipe was not feasible for large-scale production; it required expensive and volatile substances, specifically bromine.

William Perkin (1838-1907), the inventor of mauve, filed a patent in June 1869 for a new way to produce alizarin without bromine. Gräbe, Liebermann, and Heinrich Caro (1834-1910) filed a patent for a similar process just one day before Perkin did – yet both patents were granted, as Perkin’s had been sealed first. They divided the market in half: Perkin sold to the English market, and the scientists from Berlin to the United States and mainland Europe.

Because this synthetic alizarin dye could be produced for a fraction of the cost of the natural madder dye, it quickly replaced all madder-based colorants then in use (in, for instance, British army red coats that had been a shade of madder from the late 17th century to 1870, and French military cloth, often called “Turkey Red.” In turn, alizarin itself has now been largely replaced by the more light-resistant quinacridone pigments originally developed at DuPont in 1958. Quinacridones are considered “high performance” pigments because they have exceptional color and weather fastness (major uses for quinacridones include automobile coatings as well as other industrial coatings).

There is a wonderful article on the artist Johannes Vermeer (1632-1675) and his use Madder Lake. One of the topics discussed in this article is Vermeer’s technique of applying a madder lake glaze over vermillion, especially for drapery. Also, the mouth of “Girl with a Pearl Earring” (ca. 1665) was painted with madder lake! The author surmises that some of the rather monochrome flesh tones seen in Vermeer’s faces might be explained by the madder lake’s tendency to fade is used in minimum proportions. Vermeer may also have used a mixture of red madder and black to make preliminary drawing on the canvas and in shadowed areas of the flesh tones as other Dutch painters. Madder lake has been detected as an admixture with other pigments in Vermeer’s paintings. Check out this great article:

Vermeer’s “Girl with a Pearl Earring” (ca. 1665)

Detail of mouth painted with Madder Lake paint

Madder Lake pigment suspended in linseed oil

Dye vats at leather factory in Fez, Morocco

Madder Root Reds

Of the many colors that scenic artists used were pigments that derived from Madder Root. In 1916, Frank Atkinson listed the following Madders in his color palette for his “Scene Painting and Bulletin Art.”

“Madder Lake: ranges from pink to the deepest rose color, under the names of pink madder, rose madder, madder lake and madder carmine. They are the only permanent transparent reds know. Rose madder is mostly used and is very rich and transparent.

Rose Madder: Most popular of the madder group, permanent; dries slowly

Brown Madder: One of the madder family; affords the richest shadows and the most delicate pink tints. With ultramarine or cobalt and a white, a series of fine warm or cold grays will result; with blues and bright yellows it gives fine autumnal russet greens.

Scarlet madder: deep and rich; permanent; dries slow

Pink Madder: excellent; permanent; dries slowly

Madder Carmine: the carmine par excellence; very rich and permanent; slow drier

Crimson Madder: another of the madder group; bright; permanent; dries slow”

I decided to do a little research on the variations as I was curious. Here is a basic explanation to explain the production and division of reds. Robert Chencier wrote a book on the color, titled “Madder Red, A history of luxury and trade.” His madder variation tied into the creation and production of Turkey Red.

Madder red, extracted from the root of the madder plant (Rubia tinctorum), grows in many countries around the world. It was commonly incorporated into most of the maroon and ruby reds. To produce the pigment, the madder plant was uprooted and left to dry in the fields in small piles and then eventually dried in warm airdrying houses. The roots were then initially crushed and separated from the bark by sifting. Finally the roots were crushed with stones and sifted into a fine powder. Some madder could not be used immediately and was left to ferment in barrels for a few years (eg. Alsatian or Dutch Madder). But it was this beginning that became the start for a variety of red pigments.

Cloth dyed with madder root dye was found in the tomb of the Pharoah Tutankhamun. Egyptian tomb painting (from the Graeco-Roman period) often depicts the color diluted with gypsum, producing a pink color.  Oriental dyeing process of this root became the origin for “Turkey Red,” a color avidly sought after by Europeans. One story places the introduction of Madder into Italy during the time of the Crusaders in the thirteenth century. The French finally deciphered this foreign process about 1760 and were then able to dye wool, silk and cotton bright red. The quest for Turkey Red went hand in hand with an avalanche of scientific research, which not only improved the yield of dyestuff from the roots but led to its chemical synthesis and the collapse of the world-wide madder industry.

Natural rose madder supplied half the world with red, until 1868, when its alizarin component became the first natural dye to be synthetically duplicated.   Many of the nascent dye companies grew into chemical giants of our time.

Advances in the understanding of chemistry, such as chemical structures, chemical formulas, and elemental formulas, aided these scientists in discovering that alizarin had ananthracene base. Anthracene is a component of coal tar and used in the production of the red dye alizarin and other reds. It is colorless, but exhibits a blue fluorescence under the ultraviolet radiation (400-500 peak).   Madder lake contains two red dyes: alizarin and purprin. As a paint, it has been described as fugitive and transparent.

On a final note today, a lake pigment is a pigment manufactured by precipitating (creating a solid from a solution) a dye with an inert binder or mordant, usually a metallic salt. Unlike vermillion or ultramarine and other pigments made from ground minerals, lake pigments are organic. Manufacturers and suppliers to artists and industry frequently omit the lake designation in the name. Many lake pigments are fugitive because the dyes involved are unstable when exposed to light. Red lakes were often used as translucent glazes to portray the colors of rich fabrics and draperies, especially in Renaissance and Baroque paintings.

Here is an example of the madder root plucked from the ground

The brilliant ruby color derived from madder root.

Madder roots and one possible outcome.  This reminds me of the many variations when grinding lapis lazuli.  Madder root extract varies from a light pink to a deep red depending on the final processing of the root.

A contemporary version of brown madder to depict the richness of the hue for visual reference.

General Hints on Scenic Colors – Shadows

“For shadow, use Van Dyke brown with brown ochre; this can be warmed with burnt sienna, which will also raise the value a trifle. Mix a purple [shadow] from ultramarine blue, rose lake, and a trifle white.”

The above text written by Frank Atkinson in his “Scene Painting and Bulletin Art” (1916, page 165). It provides a recipe for two shadow glazes – both a warm shadow and a cool shadow. The mixture of browns and sienna was intended to be a warm glaze for many cast shadows, but not all. Often a cool cast shadow was desired in the composition. A cool purple glaze was created from ultramarine, rose lake, and a little white. Note that purple dry pigment is not used in the purple shadow glaze!

On the following page, Atkinson warns against the use purple on stage, writing:

Caution: – All purple, regardless of value, are prone to appear too red under artificial light, and to counteract this tendency, the quality of all purples should be rather too cool when viewed in daylight.”

I found this fascinating for two reasons. The first being that there is the acknowledgement that a paint color will shift under light and become something that the artist never intended for the composition – destroying the painted illusion. Secondly, he directs the painters to mix a cooler version of what they see under natural light in the studio. It is important to remember that the early twentieth scenic studios primarily used huge windows and skylights to light the space. So the majority of drop painting was occurring in natural light conditions and not artificial light conditions.

Below are some painted details from my scenery collection (Peoria Scottish Rite, ca 1902 and enlarged for the Scottish Rite Cathedral in 1920s).  They provide examples for both warm and cool shadows:










General Hints on Scenic Colors – Reflected Lights

“The reflected lights in the shadows will require orange, with a trifle of pale English Vermillion and Dutch Pink with a little burnt sienna.”

From Frank Atkinson’s “Scene Painting and Bulletin Art” (1916, page 165)

Below are some examples of an orange reflected light:

Santa Fe Scottish Rite treasury detail (1912)

Statue from Treasure Scene at St. Paul Scottish Rite (1911)

Winona Scottish Rite treasure chamber detail (1909)

Another Winona Scottish Rite treasure scene detail (1909)

Pasadena Scottish Rite Egyptian scene column detail (1904)

And for theatre context: an 18th Century scenic art example on historic flat stored in Swedish Royal Opera workshops.


General Hints on Scenic Colors – Highlights

“For highlights use flake white added to lemon or orange chrome, lemon chrome straight, or orange chrome with lemon chrome and dutch pink.”

From Frank Atkinson’s “Scene Painting and Bulletin Art” (1916, page 165)

Here is an example from Fargo Scottish Rite Treasure Chamber (15th degree) that has coin highlights illustrating the addition of white flake to lemon chrome.

This example from the Winona Scottish Rite Treasure scene shows the use of lemon chrome straight as the final highlight.

The third example depicts the use of orange chrome with the addition of both Dutch Pink and Lemon as a highlight.

To jog your memory, here are the colors that we are talking about:

1.) Lemon Chrome (my dry pigment, ca. 1980s and paste from Cobalt Studio):

2.) Orange Chrome (my dry pigment, ca. 1980s)


3.) Dutch Pink (dry, ca. 1980s)

The one color that is not mentioned is what I have come to know as Chrome Yellow and is frequently utilized in treasure scenes post-1920s. Prior to this time, the mid tone and highlights mainly derive from a lemon yellow that is warmed with an orange or dutch pink.  Chrome yellow was available in light, medium, or dark.  It is very different from the lemon chrome version, which is similar to a primrose yellow (where there is a lighter value and cool hue)

This is from my stock (medium chrome yellow, ca. 1980s)


The Brotherhood of Painters, Decorators and Paperhangers of America


Over the years, I have stumbled across stencils from the Brotherhood of Painters, Decorators and Paperhangers of America.  I have included their standard stencil from the early twentieth century and an image of their official journal.  The 1905 journal is available as a free ebook and packed full of wonderful advertisements!

Here is a brief history of the organization and some links of available collections containing various local records.

The Brotherhood of Painters, Decorators and Paperhangers of America was organized at Baltimore, Maryland, in 1887, and incorporated in December, 1894, with its general offices located at Lafayette, Indiana. Local unions belonged to District Councils. By 1913 the Brotherhood was affiliated with the American Federation of Labor but resisted all advances and intrusions of the rival Congress of Industrial Organizations until the AFL and the CIO merged in 1955. There are a few Unions that can trace its roots to the BPDPA, including the International Union of Painters and Allied Trades (a union representing about 100,000 painters, glaziers, wall coverers, flooring installers, convention and trade show decorators, glassworkers, sign and display workers, asbestos/hazmat technicians, and drywall finishers in the United States and Canada).

Here are a few collections containing records for the BPDPA.

Kent State – Local 438

Scope and Contents: BPDPA records covering the years 1898-1918 and 1930-1967, with the majority of material from late 1930s through the 1940s.

Ohio – Western Reserve Historical Society, Locals 128,129,219 and 867

Scope and Contents: The Brotherhood of Painters, Decorators and Paperhangers of America had several Cleveland, Ohio, locals of this national labor union. Local 128 is composed of paperhangers and was founded in 1897. Local 129 represented fresco painters and included a large German membership. It was absorbed into Local 428 in 1985. In 1969 the name of the union was changed to the International Brotherhood of Painters and Allied Trades. The collection consists of union minutes, dues books and records, apprentice dues books, sick and death benefit records, financial records, correspondence and miscellaneous materials.


Georgia State University – Atlanta, Local 193

Scope and Contents: The records of the Brotherhood of Painters, Decorators and Paperhangers of America, Local 193, 1905-1972 contain four minute books (1905-1911, 1927-1932, 1937-1940, and 1952-1957) that describe primarily routine internal union business, especially finances, meetings, and legal affairs. Also included is information on notable occurrences on the Atlanta labor scene such as the strike of Retail Clerks Union, Local 1063, against Kessler’s Department Store, 1937-1938. The correspondence, 1946-1965, describes membership and organizational matters as well as national labor affairs and there are also financial and membership records detailing the workings of the organization.


University of Texas – Arlington, Local 342

Scope and Contents: Correspondence, 1926-1965; minutes, 1925-1972 (1941-1972 are on microfilm); financial records, 1925-1966 (dues deduction ledgers, 1940-1956 are on microfilm); and agreements, 1945-1963. Includes minutes of the Lubbock Building & Construction Trades Council, 1952-1953.


Brotherhood of Painter, Decorators and Paperhangers of America Stencil on Minneapolis Scottish Rite Drop

Minneapolis Scottish Rite Drop created by Twin City Scenic Co. with BPDPA stencil on back.

Fargo Scottish Rite Drop with BPDPA stencil on back, similar to Minneapolis Scottish Rite drop

BPDPA stencil on back of Fargo Scottish Rite drop, similar to Minneapolis Scottish Rite drop

Here is the official Journal from 1905, available as a free ebook

A page from the 1905 Official BPDPA Journal

Glue Types – Nikawa

Nikawa is made from the skins, bones, tendons and intestines of animals or fish skins and bones, which are boiled in water to extract gelatin. This is the Japanese version of natural glue and is primarily available in a solid form – a pack of sticks (traditional), beads, or a block.  As with many other natural glue types previously discussed, it must be heated up to liquefy and use for binding and adhesion.
Here is a recipe for Sizing Japanese. The Nikawa glue strengthens the paper, constricting the fibers, the addition of alum that is combined with the glue make it less absorbent:
1. Place beads or cut the Nikawa stick into tiny pieces and place into a  qt. container. Add 200cc (approx. 1 cup) of water. Soak at least 6 hours or overnight.
2. Heat the Nikawa mixture on low heat, mixing constantly to dissolve Nikawa pieces, making sure it does NOT boil, until it melts away and the color is light brown.
3. Pour Mixture into a large bucket, add an additional 4 cups of water.
4. Add about 1/8 teaspoon of Myoban (Alum) into the mixture and mix well until Myoban dissolves. Now you have the Dosa mixture and it is ready to be applied to the paper.
5. Dip the brush into the mixture and tap the brush to remove excess.
6. Brush on both sides of the paper slowly and evenly from side to side in the same direction. If you want a stronger sizing, you can repeat this process two or three times. Allow to dry after each application.
Let this dry completely and follow same instructions for other side. Do not use a blow dryer or fan.

Here is a supplier link for information and the use of Myoban/Alum

A collection of Japanese sizing recipes can be found at . It is a Japanese blog published by Idaoy with fabulous information and illustrations of his process. He lists the ingredients and processes for various historic sizing recipes. Here are the

1926 ingredients by Mr. Urushibara’s recipe (in “The Technique of the Color Woodcut by Walter Phillips, 1926) to make enough Dosa to size 14 sheets of paper: 1/8 oz. Alum, ¼ oz (gelatin/nikawa), and 35 oz. water.


Glue Types: Fish Glue

Glue can be extracted from fish by heating the skin or bones in water. The purest form of fish glue, made from the membrane of the air bladder (swim bladder) of certain species of fish such as the sturgeon, is also called isinglass. Isinglass can be produced from various species of fish using diverse manufacturing processes.

Tatyana Petukhova, a paper conservator at Cornell University Library in Ithaca, New York. She wrote an article, The History of Fish Glue as an Artist’s Material: Applications in Paper and Parchment Artifacts. It was published in “The Book and Paper Group” (Annual Volume 19, 2000) and can be found in its entirety at

Here are two sections from her article that discuss the illumination of parchment manuscripts and experimentation with fish glue by 19th century artists.

“Illuminated Parchment Manuscripts

“In medieval Europe, parchment was the main material for writing. It was usually made from sheep or calf skin, but occasionally from the skins of such other animals as goat, antelope, and gazelle. Preparation of the parchment was a time-consuming procedure requiring special skills. One of the many steps in the process was sizing of the parchment, which enhanced its strength and prevented the writing medium from penetrating too deeply, allowing the parchment to be reused. When the parchment was to be used over again, the old ink or gouache-like medium was removed from the surface by rubbing pumice over it; the area was then softened so it could absorb new writing.

Two types of size application, coating and impregnation, were employed. The sizing solution was generally produced from scraps of parchment or trimmings of the whole skin of an animal. Small pieces were then soaked and boiled in fresh water. Fish glue was also used to size parchment.

Gouache on Paper and Board

In the nineteenth century some artists experimented with non-traditional techniques. The gouache paintings by M. Pierran, for example, which were coated heavily with glue in order to obtain a special effect, were exhibited in the 1834 Salon. These gouaches with their glossy surfaces resembled oil paintings. The technique involves application of the mixture of gouache with a large amount of gum and fish glue. These paintings over time have developed delamination and cracking.

Another method of painting with watercolor on specially prepared Bristol board was developed by C. J. Robertson, for which he received the Medal of Isis from the Society for Encouragement of the Arts, London. The process, from the backing of a Bristol board to the coating, was elaborate. When the picture was completed it was “varnished” with a solution of fish glue and then with a good quality picture varnish. “The advantages of the method are that the color, which stays very brilliant and transparent, may be worked over in a way impossible by any ordinary method. A similar method is described by Vibert.

Artists’ experiments with coating and glazing of paintings and drawings with fish glue were recorded as early as the seventeenth century. Fish glue produced by boiling of the swim bladders of sturgeons was experimentally used by Van Dyck in his tempera paintings. When fish glue was applied in many layers and in glazed coats, the film formed was easily chipped off.

These earlier attempts demonstrate that fish glue used alone forms a brittle film. As with any other adhesive, when and where it is appropriate to apply should be considered carefully. Perhaps the brittleness of the film formed by this glue motivated artists to introduce various plasticizers that are also used in conjunction with fish glue in restoration. Molasses in England and honey in Russia have often been used as natural plasticizers. For example, isinglass glue mixed with honey had been used for the consolidation of delaminated paint in Russian icons as early as the seventeenth century.”