Varnishes for oil painting according to their purpose are divided into 4 main groups. These include: coating varnishes intended for processing the surfaces of ready-made paintings, binders - to strengthen the painting layer, thinning - used to dilute the paint mass, and universal, with a multifunctional purpose. Let us dwell in more detail on the features of the top-coat dammar varnish, one of the most popular and widespread.
Burnout in the sun
It is known that the disadvantage of most dyes, both used in everyday life and used in industrial production, is their poor resistance to sunlight. The result is faded and faded clothing fabrics, room wallpapers, street banners, and many other things around us. They are usually spoken of: "Burnt out in the sun."
A similar fate will befall oil paintings on canvas, if the artist does not take care of the safety of their original appearance. The traditional method used since time immemorial is to coat ready-made paintings with special varnishes that can protect them from exposure to sunlight. They were invented for a long time, and their composition over the centuries has changed and improved many times.
What is dammar varnish for?
Nowadays, the chemical industry offers painters a wide range of means of protecting their works. One of the most common among them, as mentioned above, is dammar varnish. Applied in a thin layer, it after drying not only creates a protective film that protects the painting layer from the undesirable effects of ultraviolet rays of the solar spectrum, but also gives the overall color of the picture greater brightness and depth. In addition, thanks to him, the small details depicted on the canvas look more clearly and textured.
Another important feature of dammar varnish is its ability to withstand moisture. If the picture will be stored in a room where its content in the air is increased, then the paint may begin to peel off the canvas and fall off. No less harmful effect on the unprotected painting layer and the excessively low humidity of the premises. In this case, it may crack and begin to crumble. Especially this danger is exposed to the canvas, on which the paint is applied in a thick, thick layer.
In addition to all of the above, oil paintings on canvas can be exposed to such negative effects as a sharp temperature drop, dust settling, as well as liquids and gases getting on their surface. Thus, the coating of a finished painting with dummy or some other protective varnish is an integral part of the overall process of creating a picture.
The legacy of past centuries
The main component that is part of the dammar varnish is a resin of plant origin, which gave it its name. It belongs to the group of soft, alcohol-soluble resins, on the basis of which the manufacture of varnishes was mastered in the XVII century. It is known that artists often used them not only to cover finished works, but also added to oils, thereby achieving the speediest drying of paints.
From the history of art it is known that many masters of past centuries used balms and essential oils (gum) made on the basis of soft resins (including dammar). The most famous among them are the Venetian, as well as the Strasbourg terpine and Kopay balm. All of them gave a positive effect when used with conventional drying oils.
The effect achieved with resin ingredients
It has long been noticed that resinous ingredients with high transparency and reflective properties are able to give paintings extra brightness and depth. In addition, they significantly improved the performance of oil paints, opening up new possibilities for creating spectacular classifications on the canvas.
By this term we mean a technique in which due to the application of translucent paints over the main color, the effect of deep color overflows is achieved. Among the masters of the past, such luminaries of painting as Velazquez, Titian, Rembrandt and Leonardo da Vinci achieved the greatest perfection in it.
DIY nail polish
Dammar varnish can be purchased in stores specializing in products of this profile. One of its indisputable advantages is accessibility and low cost. However, many artists prefer to make it themselves, introducing their own innovations into the standard technology. Without touching on their professional secrets, we consider only the generally accepted version of this process.
The main component of the varnish is dammara resin, supplied to Russia from Singapore. Outwardly, it is a small transparent straw-colored granules coated on the outside with a thin layer of crushed powdery substance.
A recipe available to everyone
After preliminary grinding the resin, it is placed in a small bag of thin cotton fabric (for example, an old stocking is quite suitable), and then immersed in a solution of artistic turpentine for several hours. It is important to consider that the container with turpentine should be tightly closed during this entire period.
Being in turpentine, previously crushed granules dissolve, and all solid impurities settle on the bottom of the bag. The result is a solution of dammar resin, which should then be carefully filtered through a muslin or cotton cloth.
An important role is played by the ratio of the amount of soluble resin to the volume of turpentine, since the concentration of the finished product depends on this. According to generally accepted standards, it is 600 ml of turpentine per 300 g of resin, but many of those who prefer to prepare a solution with their own hands create proportions of components based on personal experience. In the future, if during the application of varnish on the surface of the painting it turns out to be excessively thick, it can be diluted with alcohol.
When can a painting be painted with dammar varnish?
This issue is extremely important, because technology disruptions caused by ignorance or negligence can lead to damage, and in some cases to the death of a painting. First of all, after completing the painting, you should not rush, because the linseed oil contained in the paints must have time to polymerize, that is, when it has completely dried, turn into a solid polymer. How long does it take?
In the recent past, it was customary to cover paintings with dammar, and equally any other varnish, not earlier than a year after their completion. During all this long time, the canvases had to be carefully protected not only from dust and dirt, but even from tobacco smoke.
Nowadays , artists use paints made on the basis of modern technologies, which provide them with great strength and shorten the drying time. In view of this, the minimum time interval between the end of work on a painting and its varnishing has been reduced and ranges from one to one and a half months.
How to cover the picture with dammar varnish?
The basic rule is that when applying the varnish layer one should not rush, because with rapid movements the brush inevitably captures the air, its micro-bubbles remain on the canvas, forming muddy whitish stripes. If this still happened, it is recommended to remove the unsuccessfully applied varnish with a thinner and then try again.
After varnishing is completed, the picture should be put on a flat horizontal surface and for 10-15 minutes. Allow more liquid varnish to spread evenly and harden slightly. Then they hang it in a room with good ventilation. Drying time of dammar varnish is 12 hours. Accordingly, during this period it is better not to touch the picture and protect it from dust.
Some more tips
There is another important detail that can slip away from the attention of a novice artist - this is the expiration date of dammar varnish. If you do not make it with your own hands, as described in one of the previous sections of our article, but buy it in a store, then it should be noted that after 3 years from the date of release, it loses its properties to a large extent.
As a result, the varnish layer may not completely dry and the surface will remain sticky for a long time. Dust will settle on it, which cannot be removed. To avoid this problem, it is necessary to ensure that the purchased varnish is fresh, because in the art salon it could stand indefinitely. Old varnish can be added to the paint to achieve picturesque effects, one of which was mentioned above.
At the end of the article, it should be mentioned, firstly, that dammar varnish is fire and explosion hazard, therefore, it should be handled in compliance with the necessary safety precautions. And secondly, it has a very negative property to turn yellow over time. In view of this, they are not recommended to cover paintings made in cold colors. This effect is shown in the last photo.