How Soon Can You Spray Varnish An Alkyd Oil Painting?

Oil pigment is the most complicated of all paints from a materials indicate of view when information technology comes to the eventual durability of the painting. The construction can exist roughly divided into:

1. Preparing the ground
2. Applying the pigment
3. Applying the varnish

ane. PREPARING THE GROUND

The quality of the preparation largely determines the eventual durability of the artwork. Paper, cardboard, wood, cotton and linen can be used every bit grounds for oil pigment, but not without prior treatment. An untreated or insufficiently treated footing will suck the oil out of the paint and volition eventually be damaged by the oil. A paint layer must contain sufficient oil in order to surround the pigments and form a good film. Merely and so will the pigments be sufficiently bonded and premature splitting and cracking avoided.

Gesso is used to ensure a proficient preparation
Talens Gesso is fabricated using a pure acrylic resin and is of superlative quality. Produced co-ordinate to a special formula, gesso performs the functions of the diverse layers. The layer, however, must exist thick enough, and so information technology is best to apply this in two goes. For the first layer the gesso tin can be thinned with water to an easily spreadable thickness. Next a second layer is applied, pure or slightly thinned with h2o.

For highly absorptive grounds the ground first tin can be treated with a layer of Amsterdam Acrylic binder, a pure unpigmented acrylic resin. The gesso tin then exist applied, preferably criss-cross in ii (somewhat thinned) layers.
Talens stretched canvases, roll sheet and sail boards take already been prepared.

2. APPLYING THE PAINT

There are in theory two oil painting techniques: 'alla prima' and 'layered painting'.

Alla prima
Alla prima refers to the painting being painted 'wet-into-moisture'. With this technique the colours are mixed not only on the palette, only too in the painting itself, applied wet aslope and over one another. The painting, which is ultimately congenital upward of a single layer, must be completed while the pigment is still wet. The paint tin can be applied pure or combined with always the aforementioned medium or solvent.

Layered painting
With layered painting the painting is built upward of various layers. A next layer can only exist applied one time the previous layer is dry out enough to ensure that it will definitely non dissolve. With layered painting a technique has to exist followed that is known as 'fat over lean'; every subsequent layer has to contain more oil.

You cannot e'er foresee exactly how many layers are needed to come up to a satisfactory event. Ensure, therefore, that the pigment is never too fatty and so that whatever subsequent pigment layer is nonetheless able to bond. Pure oil as a medium is certainly not advisable; the paint can then become too sealed resulting in a subsequent layer not being able to bail well. What's more than, with besides much oil there is a greater risk of wrinkling of the paint film during the drying procedure.

Fat over lean
Ensure the showtime layer is applied lean. To this finish the paint has to be thinned with white spirit or turpentine. While this layer dries it will non produce a sealed paint film, simply a porous one. Oil from a subsequent layer volition be absorbed by the underlying lean layer and secure itself in the numerous pores while drying. This volition produce adept adhesion between the two layers. As an underlying (lean) layer draws oil from the layer higher up, yous have to ensure during painting that the layer above contains relatively more oil. If this is not the case, quality problems can ascend.

The adhesion of the paint layers and the 'fat over lean' principle together too ensure that the tension between the various pigment layers is absorbed. A painting is constantly exposed to movement – on the one hand by the flexibility of the grounds such as stretched canvass, and due to fluctuations in temperature and humidity on the other. To ensure the durability of the painting it is therefore important that all paint layers tin can absorb these movements.

The more oil a paint layer contains, the more elastic it will be one time it is dry. If a painting were to consist of various layers whereby the lower layers contain more oil than the terminal layers, therefore against the 'fatty over lean' rule, the less rubberband superlative layers would and so in due course be torn autonomously by the moving layers underneath When this becomes visible, it is referred to as swell. Cracking can exist avoided by making every subsequent layer a little fatter. 'Fat over lean' can therefore likewise be interpreted equally 'rubberband over less elastic'. This makes it immediately clear why a paint layer needs to dry sufficiently earlier applying the next layer. A layer that has not dried sufficiently is often besides elastic for a adjacent layer. And that can also cause cracks to course.

It is of course up to the artist how many layers are applied when building up a painting. It is advisable though to thin the pigment with white spirit or turpentine for the outset layer. The more solvent, the leaner the paint layer. When the first layer is dry enough the second paint layer can exist applied. From this point in that location are several means forward:

Thin every subsequent layer with a decreasing amount of solvent; each subsequent layer therefore has to contain relatively more oil. This procedure tin somewhen be finished with pure pigment.
Mix the paint for the subsequent layer with a painting medium. A proficient medium consists of three components: oil, resin and solvent. The oil makes the paint fatter, whilst the solvent ensures that the paint does not become too fat. The resin every bit third ingredient increases the durability of the paint layer.
If a painting is congenital up in more two layers, the medium can exist mixed proportionally with white spirit or turpentine from lean to increasingly fatter. The larger the relative amount of medium, the fatter the mixture. For the final layer the pigment can be mixed with pure medium.

Besides the pigments used, the folder ensures for some of import properties. Linseed oil has throughout the centuries shown itself to have the best combination of properties. Every bit linseed oil shows some yellowing in time, it is sometimes replaced by safflower oil specially for white paint. This oil yellows less, but it also has some disadvantages: information technology dries more slowly. Safflower oil is therefore not suitable for pasty use and lower paint layers.

Glazing
Whether a painting is fabricated using the wet-into-wet technique or painting in layers, a glazing tin can be practical as a final layer. This is a transparent paint layer which has roughly the same event as placing a coloured canvass of glass over a picture. The moving picture doesn't change, but the colours do. A glazing tin can be applied, for example, if the artist is not quite happy nearly the colours and wants to change them somewhat without having to paint over unabridged areas. Also, the creative person may wish to achieve the visual consequence of glazing layers; an enamel-like superlative layer and deep colours. An underpainting would then exist used as a starting point to alter the colour of the entire painting with one or several layers of glazing.

Castor strokes must non be visible in a glazing every bit you lot will go along to see the brush stroke of the underlying layers through the transparent pigment; a glazing medium therefore has to period. Thanks to this property you lot tin can also brand flowing colour transitions in a glazing.

A layer of glazing has to be more than rubberband than the underlying pigment film as here, likewise, the 'fatty over lean' dominion has to be followed. Various mediums are suitable for this purpose.

Storing and drying freshly-created paintings
The drying of the oil is a chemical process that occurs under the influence of air and light. Oxygen is captivated past the oil, causing the molecules to cross link into a network. Energy is required for this oxidation process, which is supplied mainly by ultraviolet light. This entire process takes some time, which is the reason why oil pigment takes so long to dry. The greater the ventilation and calorie-free, the faster the drying. A low ambient temperature and loftier humidity adversely affects the drying process.

This is whyfreshly-created paintings take to dry in a room with plenty lite (not direct lord's day), at around room temperature and depression air humidity.

A painting has to be completely dry out throughout before information technology is varnished!

3. APPLYING THE VARNISH

Varnishes for oil paints generally consist of resin dissolved in a solvent. They protect the paint layer and determine the gloss of the work. A adept varnish must be reversible. That is to say that, for example, in the case of a restoration it should e'er be possible to remove it with a solvent without dissentious the pigment layer, also subsequently many years.

Retouching varnish
During painting sunken-in areas tin can arise. This can occur if in a detail area too much oil is absorbed by an underlying layer; the paint becomes matt and the colour loses intensity. Due to the strong suction of these areas, besides much oil would be sucked away when a next layer is applied. One time the sunken-in areas are hand-dry, utilize a thin layer of retouching varnish in gild to render gloss and colour to the area, and consequently also the harmony of the work. What'south more, this ensures that too much oil is also not sucked away from a following layer. In a thin layer after drying the varnish leaves a porous film into which a subsequent paint film tin attach. When used for this application retouching varnish can sometimes besides be referred to as 'intermediate varnish'.

In addition, retouching varnish can be used as a temporary protective varnish on paintings that are not notwithstanding completely dry. This gives the painting an fifty-fifty gloss and protects information technology against dirt. Every bit the varnish is porous (in a sparse layer), oxygen absorption and consequently besides the drying process of the paint can continue. Once the paint is completely dry a final varnish can be applied over the retouching varnish.

It is very important that the retouching varnish is always applied in very thin layers. If used every bit an intermediate varnish too much varnish will impair a good adhesion of any subsequent layer. With excessive apply as a temporary protective varnish the solvent of the varnish can dissolve the oil from the lower paint layers (that are not yet dry) and bring it to the surface. If this happens the painting may remain mucilaginous for many months or even years, and will arrive difficult to stop dust adhering to it. With normal layer thicknesses it is therefore important to wait at least 2 to three months before applying it.

Final varnish
Oil pigment dries under the influence of oxygen and lite. This is a chemic procedure. Once the paint is dry out this oxidation process does non stop only continues in an ageing process. Eventually this can be visible as corking. In one case the paint is sufficiently dry out (with layers of normal thickness this takes approximately one year, with very thin layers several months less, and with thicker layers several years) it is therefore appropriate to apply a final varnish. This final varnish slows down the oxygen absorption and consequently the ageing process. This as well determines the eventual caste of gloss and the paint is protected against atmospheric contamination.

When varnishing ensure that everything (painting, varnish, castor and trays) are at room temperature. If a painting is taken out of a cold room into a warm room in order to be varnished condensation can form on the common cold painting. Moisture would therefore exist sealed within the varnish resulting in a white brume inside the pic. What'due south more, the moisture on the painting tin can cause the varnish to dewdrop and decrease the adhesion.

Beading tin can as well occur if the paint layer is very sealed, for example when this contains a bully bargain of folder (medium, oil). In order to forestall this it is advisable to first wipe the painting with a cloth with some white spirit. In one case the white spirit has evaporated the varnish can be applied.

Glossy movie varnishes consist mainly of a resin in a solvent. In the example of matt varnishes a matting agent has been added. When using a brush to apply a varnish with a matting agent (therefore also with mixtures of glossy and matt varnish), it is important that the varnish is applied at the end in brush strokes in ane direction. This helps to ensure a uniform caste of gloss.

What'due south more, it is important that a varnish with a matting agent is applied in i layer. This helps to prevent differences in gloss and stripe germination. If, yet, matt varnish is applied with a spray can, this can exist done in several layers.

The matting agent in Talens Picture show varnish matt is a combination of waxes that flocculate nether low temperatures. By heating up the varnish ('au bain marie' or nether trickling hot h2o) the waxes are dissolved and the varnish tin be used over again.