Oil paint varnishes

No, unless the paint layer is very thin, it cannot be done earlier. An oil painting can be varnished after about a year for normal layer thickness, a few months earlier for very thin layers, and several years for thicker layers. CAUTION: If a varnish is applied too early, there is a risk that the solvent of the varnish will dissolve the oil in the paint that has not yet fully dried and bring it to the surface. If this happens, the painting may remain sticky for many months or even years, and dust adhesion is difficult to prevent.

Damar varnish is a natural tree resin dissolved in turpentine and, of the traditional varnishes, is virtually the only one still used. Damar varnish gives a high gloss. May show signs of ageing over time, such as yellowing and cracking. Dries within a few hours.

Applying a provisional final varnish is not necessary but may be desirable if the painting has gloss differences and is exhibited before the final varnish is applied. In addition, the paint is then protected from dirt.

CAUTION: If a painting has been varnished before the paint has had time to dry completely, the paint under the varnish will remain soft for quite some time because the varnish layer seals the paint from oxygen, making it difficult to continue drying. In this case, when removing the varnish, the paint may also (partially) dissolve.

When removing old varnish layers, proceed with care and pay close attention to ensure that no problems occur during cleaning.

1. Take a flat brush a few cm wide, dip it in white spirit (use only white spirit 090 for this purpose) and brush an area of about 15 x 15 cm.
2. Wait until the varnish starts to swell, meanwhile rinse out the brush and repeat the operation over the swollen varnish. It will now partially dissolve in the white spirit contained in the brush.
3. Keep repeating the operation with a rinsed-out brush until all the varnish on this spot is removed.
4. Then treat the next piece.

NOTE: When the varnish is removed, there appears to be a white haze on the painting. This will disappear when a new coat of varnish is eventually applied.

Our Amsterdam acrylic varnishes are also suitable as a final varnish for oil paint but have slightly different properties.

• They have a different gloss
• They are more thermoplastic
• They are more flexible

Differences between Talens Acrylic Varnishes and Painting Varnishes

• The Acrylic Varnish (gloss 114 and matt 115, for both oil and acrylic paint) is a final varnish, but does not have the same properties as the Painting Varnish (gloss 002 and matt 003).
• The Acrylic Varnish is a solution of acrylic resin in turpentine, the Painting Varnish a solution of low molecular weight resin in turpentine (in the spray can turpentine).
• Both resins do not yellow.
• The 002 is glossier than the 114, the 115 more matt than the 003 (glossy and matt varnishes of the same type can be mixed together to a desired degree of gloss).
• The matting agent in the 003 consists of waxes dissolved in the turpentine; the varnish appears crystal-clear in the bottle, but shows an egg gloss when dry.
• The matting agent in the 115 consists of silicas (compare pulverised glass); this varnish must be shaken well before use as the matting agent sinks to the bottom of the bottle. In the spray can, the matting agent for both varnishes is silicas.
• For an even (matt) sheen, a varnish containing a matting agent and applied with a brush should be spread in one direction. The Acrylic Varnish forms a more flexible film than the Painting Varnish. This is particularly important when used on acrylic paints, as these paints also form a flexible film.

Before applying a final varnish, a very thin layer of oil paint should have dried for at least six months, a normal layer one year, thick to very thick layers up to several years. If a dry oil paint layer contains a lot of oil, it is advisable to wipe the painting with white spirit before varnishing to ensure good adherence.

The matting agent in Talens Picture Varnish matt is a type of wax that is dissolved in the solvent and can 'flocculate' at low temperatures. Heating the varnish ('au bain-marie' or under a jet of hot water) dissolves the matting agent evenly and the varnish can be used again.

Provisional final varnish may be applied after about 2 - 3 months.

A common mistake when applying retouching varnish is that the varnish is applied too quickly and excessively.

The solvent of the varnish, if applied on an oil paint that is just hand-dry, will still dissolve some of the oil in the paint, causing the oil to lie on top of the paint and form a sticky layer. If the retouching varnish is used as an intermediate varnish that is then painted over again, there is nothing wrong.

However, if the retouching varnish is applied too quickly as a provisional final varnish, the same phenomenon will occur, resulting in the exterior of the paint film consisting of a mixture of oil and resin. This layer will remain sticky for months and patience is the only solution here.

As this is not the intention, it is advisable to wait a few months before applying the varnish until the paint has dried a little more, at least a month in the case of a very thin paint layer.

Furthermore, it is very important to apply retouching varnish sparingly in all cases. The more varnish, the more solvent is applied and the stronger the problem will be. Moreover, only thin layers of retouching varnish possess sufficient porosity, which is important for the adhesion of subsequent paint layers (intermediate varnish) and for the passage of oxygen for further drying of the paint (provisional final varnish).

This cannot be avoided and is caused by a combination of the colour used, the type and amount of thinner added and the absorption of the substrate. During painting, "sunken-in" spots may appear: the paint dulls, the intensity of the colour diminishes. Gloss differences can be adjusted with retouching varnish.