Oil Art

 

Painting Surfaces

 

Surface (also known as support) it's any physical material like paper, canvas, wood, fiberboards, PVC, copper, aluminum, paperboard, glass, wall, gypsum… All the different surfaces can be separated in two main groups:

  1. Flexible – canvases, papers...
  2. Rigid – wood, fiberboards, PVC, copper, aluminum, paperboard, glass, wall, gypsum...

In our time the most popular and usable surface is the canvas, but his status as a painting surface is relatively small. The old masters performed their masterpieces on wooden panels. In that period the most popular wood was oak and birch in the northern Europe, poplar was used in Italy (The famous portrait of Mona Lisa by Leonardo da Vinci 1503 was painted on poplar). Metal mainly copper was the second choice of the painters; it wasn't so popular as wood. The paintings on the rigid surface have several advantages:
* It is easier to paint on rigid surface.
* The most important thing is that the surface will serve as a good "guard" of the painting film. It will protect the painting from casual damage that can be caused by bend of the canvas. That bend can lead to cracks in the painting film or the "ground". The canvas can be easy ruptured, and it can't happen with a rigid surface. But rigid surfaces have disadvantages too, therefore you'll need to learn more about the existing surfaces and find which one is best for you.

Flexible Surfaces: | Canvas | Cannabis, Hemp | Linen, Flax | A little more about the Cannabis and Flax
| Cotton | Jute, Hessian | Synthetic Fibers | Paper

Rigid surfaces: | Wood Panels | Plywood | Fiberboards | Particleboard | Metals | PVC, polyvinyl chloride
| Other Surfaces (Supports)

 

Flexible Surfaces:

Canvas

Canvas is a term applied to tightly woven fabrics that are used for sails, tents, awnings and paintings. Canvas comes in a wide variety of textures, qualities and dimensions. It can be chosen for a specific effect desired in a given painting such as: an extra smooth surface for detailed portraiture, a bold texture for impasto, or an abrasive “toothy” surface to enhance adhesion for collage.

The Structure of Canvas - the weave of canvas goes in two directions. The yarns running the length of the canvas are referred to as the “warp”. The yarns running across the width of the canvas are referred to as the “weft or filling”. The strength of the canvas is based on yarn thickness, closeness of construction, and fiber quality as indicated by its tensile strength.

There is an important difference between the regular materials and the ones that are designed for painting. Before I'll explain that difference I want to remind you what happens with natural materials after they get wet: they shrink! Take for example the jeans, after washing they become smaller and tighter, that is because they shrink. So what is so special about the artist grade canvases? During the spinning and weaving of artist canvas production, stresses are placed on the canvas fibers that stretch them beyond their natural dimensions. When wet (during sizing or priming), the canvas reverts to its natural state by pulling back to the relaxed fiber dimension (it shrinks). The term “shrink” in a woven canvas refers to the ability of the fibers to return to their normal relaxed state when subjected to moisture. It is the potential shrink in an artist canvas that keeps it taut on the stretcher frame through constant changes in temperature and humidity. A canvas that has been pre-shrunk is normally unsuitable as an artist canvas, because it has lost the ability to shrink. Pre-shrunk or chemically treated canvas tends to sag during periods of high humidity.

There is a small test that you can do, if you want to distinguish between the artist grade canvas and the regular one.
The test is very simple you can do it without harming the material. If you will stretch the material with two fingers of your hands, it will live a stretched stripe; you'll see even the places were your fingers was holding the material. That stretched stripe is what you are looking for; this will tell you if the canvas is an artistic grade.
Here is a test that I did with two different linen materials (fig.1): one of them I bought in a regular material store and the second one in a special store for artists (it is Belgian linen known as one of the best canvases).

belgium artistic grade linennon artistic grade linen
Fig 1 At the left side you can see artistic grade Belgian linen with a bright brown color, and at the right side is non artistic grade linen with a beige color.

You can feel the difference between the materials when touching them; the Belgian one is very strong and stretched, when the second one is like cotton material. I took the corner of the material and stretched it with the fingers (fig.2 the arrows on the picture shows in what direction to pull the material and the head of the arrows is the place where the fingers should be placed).

belgium artistic grade linenbelgium artistic grade linen
Fig 2

The materials after I stretched them:
belgium artistic grade linenbelgium artistic grade linen
Fig 3

From the fig.3 of the materials after the stretch, you can see the difference: the material that was purchase in a regular material store didn't changed much, compared with the Belgium one that did changed. You can see a stretched stripe, and in the circles you can see very clearly the place where the fingers were. You can remove that stripe by stretching the material with the directions of the running yarns.

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What fibers are used for canvases?

 

Cannabis, Hemp

cannabis sativa
HEMP
Cannabis Sativa

The first use of the cannabis was in 8000 B.C. in China, the earliest known fabric is woven from hemp for cloth. In the 14-15th century Renaissance artists perform their masterpieces on hemp canvas. In 1537 hemp receives the name Cannabis Sativa, the scientific name that stands today. In 17th Century Dutch Masters, such as Van Gogh and Rembrandt, painted on hemp canvas. In fact the word canvas derives from the word "cannabis", in our days that word describes each of the coarse fabric. 16th-18th Century: Hemp was a major fiber crop in Russia, Europe and North America.

Ropes and sails were made of hemp because of its great strength and its resistance to rotting.  Hemp paper does not turn yellow and disintegrate, as wood pulp paper does. The Library of Congress reports that 300-400 year old hemp paper is still in good shape. However, 97 percent of the non-fiction books printed between 1900 and 1939 on wood-based paper will be soon unreadable.

Hemp was a major crop until the 1920's, supplying the world with its main supply of food and fiber (80% of clothing was made from Hemp). The material that is made out of hemp is very strong and stable. This durable canvas was used by the great masters whose works we can see today. Hemp canvases are the best from the existing naturally canvases, the only problem is to find it and the good one.

 

 

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Linen, Flax

linum usitaaissimum
FLAX
Linum Usitatissimum

This plant is known about 10,000 years, may be even more. It was cultivated in the glossary iconDelta, that land is placed at the mouth of the Nile River ( Egypt ). In the period of the middle Ages (10-14th century), paintings were done on wood surfaces for churches; the wood was prepared by gluing it with linen strips. In 15th century Venetians used large linen canvases as a support for their paintings. The first paintings on that kind of support were done with Tempera paint (made of pigment and egg yolk). In that period the paintings that were executed on canvases were cheaper that theglossary icon"Fresco" ones, but that was right till the Venetians started to use the oil colors instead of the Tempera.

The quality of flax varies according to soil and weather conditions. Ireland , Poland , Hungary , Romania and Russia produce linen of varying qualities. However, Belgium is the leader, in growing and producing the finest quality flax and artist grade linen.

The hemp and the linen come from the same genus of plants; they have the same "bamboo" body. The fibers (that are used in fabrics) are joined to the hollow woody core. The transition from hemp to linen painting canvases had occurred smoothly, because the painters accepted two of them. The fabrics woven from linen, is good as well as the hemp ones, they have pretty much the same characters.
Linen and hemp have often been confused as the two fibers can only be properly identified by examining them under the microscope. The coarser linen fibers, look and feel just like hemp fibers when spun and woven into cloth. Hemp can even be refined and bleached whitish, to resemble high-quality linen; but this takes painstaking efforts, and hemp is most often found in its coarser state.
There is a chance that the transition from hemp to linen occurred smoothly not only because the good quality of the two kinds, probably the painters simply didn't know with which one they work. Linen canvas is the most popular and expensive in our days.

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A little more about the Cannabis and Flax

stalk cross section
Hemp and Flax stalk cross section

Two of the plants have the same "bamboo" structure, therefore the main steps in production of the fibers is identical.

Harvesting
To preserve the full potential of each plant, it is pulled out of the ground. In this way, the maximum length of fiber is obtained.

Retting
The seeds are removed, and plants are left on the field to be exposed to the elements. Dew Retting decomposes the adhesion of the fiber within the woody core through bacteria. It is a controlled rotting of the plant stalk. If left undisturbed, the plant would start to rot and it would become useless. Another way known as Water Retting was most used in the past, plant fibers were submerged in the river or in water tanks. Today this technique is rarely used because of cost and pollution. These techniques were the "mechanical" ones. Modern methods are being developed which rely upon chemical rather than mechanical processes because they are faster, less labor-intensive and therefore less expensive.

Braking
The woody central core is broken into small pieces that are between the long plant fibers. Egyptians laid the retted plant stalk on a stone and beat it with a mallet. Variations of this method were used up until the industrial revolution.

Scotching
This removes broken fragments of the woody core that remain after Braking, and at the same time the long fibers are separated from the shorter ones. In the middle Ages this was done by passing the fibers thru a "comb" (wood plate with a lot of nails). Today there are another ways to do that.

Spinning and Weaving
The fibers are twisted together to obtain a yarn. Finer yarns are generally spun with water (wet spun) and the coarser yarns are dry spun. The fine ones are used for voiles; laces… and the less noble grade are made into cleaning rags, dish towels, sacks, and canvases. Hemp canvases are made from "Cannabis Sativa" species and flax canvases from "Linum Usitatissimum" species.

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Cotton

gossypium barbadense
COTTON
Gossypium Barbadense

Cotton has been cultivated for over 8,000 years. It is generally believed that the first cultivation of cotton was in India , though it grew wild in several locations around the world.  People living in Egypt's Nile Valley and across the world in Peru were also familiar with cotton.

Cotton is a natural fiber of vegetable origin, like linen, jute or hemp. Mostly composed of cellulose (a carbohydrate plant substance) and formed by twisted, ribbon-like shaped fibers, cotton is the fruit of a shrubby plant commonly referred to as the "cotton plant".

After the cotton plant blooms the pod enlarges into a cotton boll. Approximately two months later it is ready to harvest. After cleaning and removing the seeds the yarn is obtained.

Today cotton it's the most saleable material not only for clothing industry, it's as well saleable for art. Most of the canvases in the art magazines are cotton canvases with a layer of acrylic glossary icon"Gesso".
As compared with linen and hemp, cotton yarn is thinner and flat, the material is smoother, and it doesn't have such an interesting texture.
Cotton fabrics are basically unprotected cellulose, which is easily attacked by acidity. The exposure to the acidity from air pollution and ultraviolet light over several decades will substantially weaken a cotton canvas. This can be somewhat compensated for through proper sizing with acrylic mediums.

French artists did not adopt cotton canvases as readily as they had linen ones. But even at the beginning of the 19th century, the Industrial Revolution and the large production of cotton in the United States started to erode away the popularity of linen, more time consuming and costly to produce. French painters had traditionally painted on strong and durable fabrics—hemp and linen, and the transition from hemp to linen painting canvases had occurred smoothly. The artists were aware that cotton fabrics are not that good as the hemp and linen, that's why it was not well adapted as hemp and linen for art supports.

Cotton is weaker than the two other fibers and much weaker when wet; it will also not resist bacterial growth as well. Only starting at the turn of this century did painters begin to paint on cotton canvases, because linen fabrics had by then become much more expensive. Even today, artists who are concerned with the durability of their works still favor linen over cotton when it is available and affordable. At a study of French painting canvases, no cotton was found before the end of the 19th century.
Another disadvantage of the cotton materials is the fact that they are thin especially factory prepared canvases. If you decide to paint on cotton canvas, it is always better to find heavy weight cotton 340-430 gr/m². It is recommended to purchase material from art store.
There are canvases that are woven from linen and cotton together, any mixtures of different fibers are not recommended; their unequal absorption and discharge of atmospheric moisture will cause variations in tension.

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Jute, Hessian

corchorus capsularis
JUTE
Corchorus Capsularis

For centuries, Jute has been an integral part of Bengali culture, which is shared by Both Bangladesh and West Bengal of India .

Jute is often found in rough fabrics, such as burlap sacking. It is inexpensive and sometimes used by students for sketches.

Jute becomes extremely weak and brittle with age and should not be used for permanent painting. It will most often deteriorate before a good cotton canvas, linen or hemp will last even longer. Jute is easily rotted by water compared to other materials.

Those artists, who are fond of its rough and heavy surfaces, should be able to find a heavy linen or hemp textile of comparable weave to use in its place.

 

 

 

 

 

 

 

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Synthetic Fibers

There are canvases made from nylon sailcloth, acrylic fiber, polyester, and other synthetic textiles that can be used. More people are discovering the strength and durability of using a polyester fabric. This material is the modern solution to create a totally chemically compatible environment. Polyester is almost flawless, and it has a real fine surface. It isn't affected by moisture at all, and heat or cold causes it to expand and contract much less than natural fibers. Because this polyester fabric moves the least, it is a very stable fabric to paint on.
But don't forget that unlike linen, for example, the synthetic fibers hasn't been subjected to the test of time.

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Paper

paper stack
Paper stack

Oil painting on paper is not recommended, it is not professional and not archival. How far back in history paper was used as a combined ground and support nobody knows, because so few examples have survived. Plain paper, paper sized with gelatin (to minimize or retard the inevitable embrittling effect of aging oil paint), and parchment paper which will take oil colors nicely have always served the artist for small sketches, color notes, and other purposes where longevity of results is secondary. No major works by great painters have come down to us; because of disastrous failures no concerted group revival of the practice lasts very long.

Paper and oil paint do not seem to go well together, mechanically or optically; they are not sympathetic or "naturals" like oil on canvas, tempera on gesso panels, and watercolor on paper. It doesn't have structural strength and stability and the resulting works are usually very fragile. Works on paper must undergo extreme restorative and conservative treatments, usually within 35 years, even when painted on 100% rag paper mounted to wood panel.
Anyway what is a good paper?
Paper used by artists, for drawing, sketching, or other techniques, should not become brittle, should be strong enough to resist erasure or scrubbing, and should discolor as little as possible as it ages.
Paper is made of pulp that is mostly glossary iconcellulose. The cellulose is usually derived from various vegetable fibers, chiefly cotton and linen, or from wood pulp. If manufacturers use wood pulp, they must separate the cellulose from other undesirable glossary iconlignin components in the wood by cooking and chemical processing. If this is not done, the lignin causes the paper to darken. Cotton or linen pulp requires less refining and usually yields a stronger paper.

Several different designations are used to describe the quality of cellulose in paper, and these can be somewhat misleading.
"100% cotton" - top of the quality scale, the paper is made entirely of cotton (usually from both lint and rag) and includes no linen or wood cellulose.
"Rag paper" - some rag content is included in the paper, often mixed with linters or wood cellulose. (The label can also refer to papers made with a cotton, hemp and linen mix.)
"Wood free paper" or "High alpha cellulose" or "Wood sulfite paper" - the highest grade of wood pulp paper (which may contain as much as 93% cellulose).
Cotton cellulose is up to 10 times stronger than wood cellulose and naturally lignin free and acid free. Some residual lignin and chemicals remain in chemically extracted wood cellulose, which cause embrittlement and acidification over time. For this reason, wood pulp ("alpha cellulose") papers should generally be avoided for archival or museum quality artwork. Papers made from 100% cotton, 100% linen, 100% hemp or pure cotton/linen/hemp rag, are all suitable for artistic use.
The ideal paper should last for centuries under normal storage conditions, and papers that can meet this standard are referred to as archival quality.
Manufacturers treat most papers with a sizing material to make the paper less absorbent.
The acidity of the paper is an important indicator of its potential longevity. Paper with a high acid content will age badly, darkening and becoming brittle with time. To be acceptably neutral or acid free, artist's paper should have a glossary iconpH reading between 6 and 8. This requires that the cellulose pulp be neutral and that the sizing be free of ingredients that cause acidity.

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Rigid surfaces:

Till now we've spoke about flexible supports, let's describe some of the rigid ones. There is a difference when working with panels or with flexible support. First of all the paintings that are done on panels have smaller size, as compared with canvases that can be huge. The panels create a very stable, durable and strong support; it creates a "trusty" support. The primary disadvantage of plywood or wooden panels as supports for painting is their tendency to emit acidic vapors. This out-gassing phenomenon is extremely dangerous to the paint film. The only reason why old paintings on wooden panels survived is, properly applied glue gesso ground which contains calcium carbonate (Chalk, Marble, Whiting = CCaO3) effectively acting as buffer agent against those acid vapors. The painters always were seeking for a well aged panel, because it emits less acid gases. There a porous supports like the wooden panels and nonporous aluminum, PVC, glass metals.

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Wood Panels

wood
Wood log

Wood panels as supports for painting have been used from the earliest beginnings of painting. Wood types that have been used by artists include: poplar, oak, linden, pine, cedar and various hardwoods, such as mahogany and walnut. The wood selected by the early Italians for their panels was mostly poplar; that used by the Northern painters was oak. Eighteenth- and nineteenth-century Northern panels are usually mahogany.

The best wood panels for painting are well seasoned, air-dried glossary iconquarter-sawn hardwoods to avoid warping, shrinking, and it holds paint better. The quarter-sawed wood is to be preferred since the grain on the front and back of the panel is more nearly the same. In England well-aged boards from old paneling or furniture were often used, and the painters prefer them to new boards where the reduction of the vapors was higher. It is very important for the wood panels to be well aged because of the content of water that can cause the board to shrink and wrap. The wood of young trees is less valuable than that of old ones. When the panel is prepared for painting, it should be given the same number of priming coats (size and ground) on front and back, so that the tension on both sides is equalized. Finally, a coat of oil paint should be applied to the back to correspond to the picture on the face of the panel and to protect the back of the panel from moisture.

Wood expands in dampness, and in warmth will shrink very considerable through loss of moisture. Even very old seasoned wood is still subject to these conditions. The dried paint on a wood panel cannot follow the movement of the wood and may easily chip off. To prevent the warping of the wood panels, glossary iconreinforcement strips are developed into the back.
In the case of coniferous woods resin which exudes must be removed by chiseling it out. Wood which is free from knots is preferable. Knots must likewise be chiseled out. The holes can be filled with glue and pieces of wood or saw-dust, or with gypsum and glue. The sides of the panel should have a little grain, because the priming coats needs to get a good grip on them.
glossary iconRembrandt for example used oak panels for his major paintings. He also used poplar, mahogany and walnut. Most of the panels consist of only single piece of wood; those are usually the smallest panels. Some of the panels have two and others three parts, the correlation between the number of parts and the format is not a regular one, but the largest usually consist of three pieces. The parts are joined with the edges of the boards that are glued against each other. The grain of the wood as a rule runs parallel to the length of the panel. The majority of the panels are beveled down at the back along all four sides to a thickness of a few millimeters at the edges, probably to allow the panel to be fixed into the shallow rabbet of a frame later. Practically all seventeenth-century Dutch panels correspond to this description. The thickest part of the panels - including the large-format ones made of more than one part - usually measures about one centimeter.

There are a lot of boards that are made of saw-dust; the difference is the process and the size of the dust. There are some boards that are made from fine layers of wood that are glued together.

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Plywood

plywood panel
Plywood panel

Plywood is made by gluing several layers of wood together. The center of the ply boards, the "core", is made of thicker piece of soft wood to witch have been glued on both sides thinner sheets of harder wood, the so-called veneer. There is a five-ply board used for doors and furniture witch is highly regarded. The veneer must be glued with glossary icon"alternating grain direction", it makes the plywood stronger.

There are two kinds of veneers: sawn and peeled.
The peeled veneers are the most used ones; they are made by soaking and steaming the logs and then putting them through a machine that peels the thin veneer from them with a knife blade in a rotary manner.
The sawn ones are less used, the disadvantage is that sawing will waste too much wood; more sawdust than veneer is produced, but they are better than peeled veneers. Peeled veneers usually curl up in trying to return to their original spiral position in relation to the core of the tree.
It is not recommended that any of this material be cut with a handsaw, as the outer plies are liable to be loosened and broken away at the edges, a circular saw or band-saw is better, because the teeth go in one direction only. But the better option is to go to carpenter; you'll get a board with straight edges and wanted size. If the size of the desired board is big (45cm and more), it is better to reinforceglossary icon it.

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Fiberboards

fiber board
Fiber Boards

Any of several types of engineered wood panels made from sawdust. The sawdust, with or without the addition of polymer resins, are formed into boards using heat and pressure. There are three categories of fiberboards; the difference is their density:
*Hardboard
*HDF
*MDF
But fiberboard manufacturers often blur, stretch, or interchange these terms. A useful distinction can be made between "wet-process" boards (most Hardboard) and "dry-process" boards (HDF and MDF). The fibers in wet-process boards are "glued" back together using the relatively unstable lignin resins found in the wood; dry-process boards substitute stable synthetic resins to bond the fibers together. The fibers in wet-process boards are interlocked in two dimensions, at best. These boards tend to separate in layers, distort when the fibers expand, and have very porous edges. Dry-process boards are made with fibers interlocked in three dimensions. This makes for a more cohesive board which minimizes de-lamination and edge porosity, and increases dimensional stability.

Dry-process fiberboards are very stable and make excellent art panels; choose them over wet-process boards for this purpose. MDF and HDF are very similar panels and share most of the same qualities; they tend to differ only by a small amount in density. The manufacturing process of these products usually results in the thinner panels having slightly higher densities. Panels of a half inch or more are generally MDF; panels of a quarter inch or less usually fall into the category of HDF, though these are generally called "thin MDF" (TMDF) since the public is more familiar with the term "MDF' than "HDF'. Fiberboard should not be confused with cheaper particleboard.
Masonite® is a registered trademark of the Masonite Corporation. The term is often and incorrectly used to refer to any brand of hardboard, which was invented by William H. Mason in 1924. The Masonite Company, which he founded, uses the name Duron® to refer to its current hardboard products (which are "wet-process" boards).
One of the problems that are common to fiberboards is their tendency to curve and bend by their own weight if left standing on edge. Another problem is: if the painting is dropped, there is a big chance that its edges will crumble especially the corners. These can be prevented by glossary iconreinforcement and framing. Fiberboard is prone to warping, particularly in humid climates, but this risk is reduced by priming the front, back and edges of the board. You can seal just the back and the ages of the prepared board with couple of coats of house paint, or polyurethane varnish, or shellac, or shellac and an oil urethane finish.

The panels are available in two forms: tempered and untempered. Both untempered (or standard) and tempered panels can be used by the artist. They are made by the same process, the only different is the final step of the tempered, in witch a small amount of oil (usually linseed)is applied on the panel surface and then baked. Most of this oil is flashed off when the boards are baked at temperatures about 400 degrees F. This "tempering" oil is invisible and does not leave an oil residue on the panel that can cause adhesion problems, as did the outdated hardboard. The purpose of this process is to make the board stronger and less prone to warping. Unfortunately, artists and conservators have incorrectly been led to believe that even today's tempered hardboard is impregnated with a lot of harmful oil.

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Particleboard

particle board
Particle board

Particleboard, sometimes called chipboard (Flakeboard® is the company name of an early maker of particleboard) is a panel made of waste wood that has been chipped into small splinter-sized bits, and then glued back together using synthetic resin polymers. It is inexpensive, and resists warping. It is commonly used to make low priced furniture, cabinets, and shelving. It fractures and crumbles easily. Its delicacy in that regard makes it largely unsuitable for use in artist panels. It should not be confused with the much higher quality fiberboard.

 

 

 

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Metals

Metals requires oilier and not liquid (water base) primers. All metals will expand and contract with temperature.

Copper - a ductile malleable reddish-brown corrosion-resistant metallic element.
These plates have been used as supports for oil and oil resin paintings from early times, particularly in Holland. These have been most successful when the picture were small and consequently were preserved with more than normal care. Cooper is soft, is easy bent, and its coefficient of expansion is high. In the past, the flexibility of thin metal sheets and their susceptibility to denting by minor blows combined to cause frequent blistering and peeling of the paint film. But that's a very interesting support, because it gives an entirely new sense of dimension and depth to the work.

A cooper plate must be cleaned from colored iridescent oxide, it's very important to do it properly otherwise the painting will turn green. You can do it by scrubbing the surface with fine grit paper or otherwise roughened in circular motion .The sandpaper or the metallic wool will provide the copper with a "toothy" texture, the paint film that will be laid over can dig into by using the nooks and the crannies. After that wash the plate with dish soap and wipe the surface with rubbing alcohol, allowing the liquid to evaporate. It's very important not to touch the copper plate, since fingerprints will show up later.

All that will provide us with mechanical bond; you can make it even stronger by brushing some garlic fresh juice over the copper and let it dry. Garlic is acidic and the juice from the garlic will eat into the copper (it also used to degrease the surface). The chemical bond can be provided by using resin, it acts a lot like very strong glue; thinned mastic varnish which penetrates underneath the color skin will work just fine. The resin part is optional, but it will help if you use it.

White lead ground to as thick a consistency as possible in boiled linseed oil is then put on with an brush in a stippling manner, very thinly, like a veil, but several times, over the metal. Care must be taken to see that each coat is dry before putting on the next. The first coat must be thinnest and leanest.

On the layers of the lead paint brush a thinned transparent wash of raw umber. Let the panel sit two weeks or more. Carefully wet sand the surface by hand outdoors until the transparent raw umber wash is completely gone. Some recommend letting the primed panel sit for at least 3 months before painting on it. Never sand the dry surface, lead white is very poisonous. Another important thing is to do the same on the back side of the panel; it is still the same copper that needs to be sealed. Because of the fact that copper is easy bent it will always be a good decision to reinforce the panel with some kind of frame. Color usually will hold very well on copper plates if they have been correctly prepared.

Aluminum - The use of modern acrylic laquers or polyurethane automotive and aircraft industrial catings on honeycombed aluminum or fiberglass-coverd aluminum panels is one of the most permanent means of painting available today. The most known supports of aluminum is the honeycombed aluminum. They are light in weight, thus suitable for large paintings. Any of grounds can be applied, oil, gesso, alkyd, emulsion. Before the ground it is better to lightly roughen their surface with fine sandpaper. Aluminum panels are degreased with solvents such as mineral spirits, denatured alcohol, acetone or naphtha. Do not use any cleaner containing ammonia or other alkaline substances as aluminum will tend to react chemically.

There is another kind of support known as "DIBOND panel". It is a deluxe museum grade panel, and it is rated as a very archival product. DIBOND - is made of two lightweight sheets of aluminum with a Thermoplastic Core. It comes in large sheets but can easily be cut to size. Often used by Sign Manufacturers, it is gradually becoming popular as a Fine Art Painting Support. It will not warp, or deteriorate and will produce no '"out gassing" that can harm the painted surface. It is designed to stand the test of extreme weather conditions. It is coated with polyester paint to prevent oxidation. It is very light in weight and it is conservator recommended, definitely the first choice from the rigid supports.
go to step by step guide Gluing a canvas to a DIBOND (aluminum) panel with Beva 371 "Film

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PVC, polyvinyl chloride

It's a synthetic material, it looks like plastic and it has variety of colors. It can be a very good base, second choice after the aluminum DIBOND, since it will not react to humidity and temperature change.

 

Other Supports

There are other different supports like glass or marble or any other minerals that can be used. One can paint on such bases without applying a ground, or one can give them a coat of oil color, the same as with metals.

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