A Word About Varnish

Varnish is a clear, colorless solution containing a solvent and either a natural or synthetic resin that has been used for centuries on oil paintings and more recently on acrylic paintings.

Varnishing your paintings adds a layer of protection and can measurably affect its appearance.

Air contains a variety of pollutants that in time will cling to the surface of a painting and will alter the colors. Besides the air, your painting will be susceptible to moisture, including humidity, liquids, dust, and other contaminants. Most conservators recommend varnishing paintings because environmental pollutants are more easily removed from the varnish layer than from paint layers. Some prefer varnishes containing synthetic resins, which allow for the most reversible, least invasive conservation treatments. Some artists prefer more traditional varnishes containing natural resins such as damar and mastic, which are slower to dry than synthetic resin varnishes and, therefore, are more easily applied with a brush. But there are drawbacks to using traditional varnishes.

Color and Surface Unification 

 When you apply varnish, you will notice the color intensifies. A gloss varnish will deepen the color, while a satin finish will slightly strengthen the appearance.

Applying varnish also helps to create a unified surface. Sometimes a finished painting will have both shiny and dull areas. This variation can happen for several reasons.

Mixing paint brands-Different brands of paint use different ratios of ingredients (binder/pigment) and the types of fillers may differ. This inconsistency results in different levels of sheen.

Using Medium-Some oil painters use medium to control the viscosity of their paint. Some mediums, like Liquin, are glossy. If you have a different amount of medium in each stroke, you are likely to end up with an uneven surface.

Glazing - A glazed layer of paint will dry glossy. If you glaze only parts of your painting you should varnish it to even out the surface sheen.

When to Varnish

How to decide when it is safe to varnish is tricky. Drying rates vary greatly based on the thickness of the paint and on the temperature and humidity levels they are exposed to.

There’s no hard and fast rule. Thicker paint will dry slower while thin layers of paint will dry faster. The fingernail test is one way to determine if your painting is dry enough to varnish. Press a fingernail on the paint. If it can leave a mark, the paint is not dry enough to varnish. If it doesn’t leave a mark, like a dent, then you can varnish it. If your style of painting is impasto, you may have to wait a year to varnish.

Types of Varnish

There are several types of varnishes on the market. They include traditional natural varnishes both hard and soft, and synthetic varnishes.

Traditional Natural Varnishes

Traditional natural varnishes include Dammar, Copal, Amber and Mastic.

Copal and Amber varnishes, referred to as hard varnishes, were used by the Old Masters.

They are a golden in color and give a rich glossy and enamel-like appearance. However, they are susceptible to cracking, extensive yellowing and become increasingly difficult to remove from painting over time.

True hard Copal and Amber varnishes are rare in the world today, though some specialist manufacturers still offer unique historically-accurate painting varnishes.

Dammar (can be spelled Damar) and Mastic varnishes are referred to as soft varnishes because they dissolve in solvents such as turpentine and mineral spirits. They can be removed from an oil painting surface without greatly affecting the paint layers below.

Dammar varnish comes from tree resin and is paler than Copal but has great viscosity and is still used commonly in oil painting today. However, Dammar (because it’s a natural resin) has a tendency to yellow over time. It also becomes more brittle as it dries, leaving your canvas more likely to crack if the canvas is disturbed.

Synthetic Varnishes

Some examples of synthetic varnishes are MSA, Gamvar, and Alkyd Synthetic Resins.

Synthetic varnishes offer a lot of advantages over the traditional natural varnishes including:

• A clear coat on the first application that stays clear over time, therefore non-yellowing and more flexible.
• Are available in liquid or aerosol form, are readily available and cost-effective and they come in a variety of sheens, such as matte, satin or gloss.
• They allow for relatively easy removal with less risk to underlying paint layers.

Alkyd Synthetic Resins such as Schmincke Picture Varnish provide a glossy, non-yellowing, colorless, highly resistant topcoat. but they must be applied after eight to twelve months.

Mineral Spirit Acrylic varnishes (MSAs) have a high molecular weight and tend to offer a better protective surface, have greater elasticity and more resistance to blooming. Must be applied after eight to twelve months.

If You Can’t Wait

If you need to show or sell a painting before it is completely dry, you can use retouch varnish. Retouch varnish offers some protection and unification of color, though it’s not as strong a coating as a regular varnish. Some recent varnishes also have the great advantage of being able to be applied when the painting is just touch dry – rather than waiting for the painting to be fully cured.

Gamblin makes a varnish called Gamvar which has been developed specifically for this purpose.

Drying Time

Drying times of varnishes vary, depending on the absorbency of paint, ground and substrate layers. Paintings on panel supports, for instance, might absorb less varnish and therefore dry more slowly. At any rate, try to avoid any dust settling into the fresh varnish layer. Place your varnished painting away from drafts and if possible, keep it covered.

Varnish Need Not be Permanent

Varnishing a painting need not be permanent. After a varnished painting has lost its luster over time, the varnish layer can easily be removed, taking the built-up of pollutants and particles with it. (As a general rule, varnish should be removed and reapplied every fifty years or so.)

Workshop News

The first week of class went really well. The room is quite large and the supplies were well organized so that all of the students had everything they needed at their table. The door was open and the fans drew air to the outside. Everyone was careful and wore their masks. As I worked, my actions were taped and transmitted on a large screen. Here’s a photo of the first class at Artsplace. There are eight students, each with their own table.

Everyone seemed to be enjoying their time back in the classroom. It sure feels good to be teaching again!

Aerial Perspective in Landscapes

Aerial perspective or atmospheric perspective refers to the effect the atmosphere has on the appearance of an object as it is viewed from a distance, the appearance being its color and value.

In my last post, I talked about the curtains of water particles that inhabit the atmosphere and how these curtains change the color of the sky as it approaches the horizon. The same effect holds true for landscape subjects in the distance. As colors recede from the eye over terrain, they become cooler, with the exception of white. A cooler color means a color that tends to contain blue, while a warm color is made up of reds and yellows. In this picture, the trees in the distance appear cooler in color and change to blue in the far distance.

Color Changes

The greater the distance and the more atmosphere, the bluer the distant objects become. As your eye travels, you will notice that the color yellow disappears first, including all of the yellows that mix with other colors such as yellow green, browns, and oranges.

A warm yellow green in the foreground will transition to an emerald green and then a cool blue-green.

In this picture, the closest greens contain more yellow, and as we look further, the yellows dissipate, until the greens in the distance become a blue-green. The sky at the horizon is also lighter and changes to a gray-rose in color.

Reds will prevail slightly longer than yellow, before they too succumb to blue. That’s why mountains tend toward a warm purple before they change in their farthest distance to blue. Atmospheric particles affect the value of a color as well as the temperature in a landscape. You can see in this photo of a mountain range, the transition from green to blue-green, to purple-blue to blue.

Value Changes

All colors will become lighter as they recede, the lightness tempered by the prevailing sky color. As I said last week, whites tend to become slightly warmer and darker as they recede, due to the atmosphere.

 As you would expect, objects close by are deeper in color, their shapes are sharper and the values are more distinct.

It’s important to note that a flat ground plane is always going to be darker than the sky (except when snow is involved), but never as dark as the upright planes such as trees and buildings.

The Sky: A Rainbow of Color

It’s tempting to just pick a nice warm blue and cover the sky in your painting with it. The fact is, the sky is not just blue, but a whole rainbow of colors depending on which direction you are looking and the condition of the atmosphere on any given day.

 The Earth’s Atmosphere is Made of Curtains of Moisture

The earth’s atmosphere is a receiver of light, and it acts as a diffuser of light. It is composed of suspended moisture in the form of gases that veil our view like a series of thin curtains. The veil of moisture fluctuates from dense to light as the weather patterns and the moisture in the atmosphere changes.  Looking through the atmosphere from a close distance, the view is decidedly clear and sharp. It is for the most part colorless. As the distance increases and the atmosphere becomes thicker, it takes on an opaque blue cast. This blue affects the darks and near darks more than it does the lighter tones. However white or near-whites take on a slightly warmer, darker tone as they recede into the distance because of the particles in the atmosphere.

The Sky Rainbow

In this picture, viewing the sky from different angles on a long flat plain, you can see how the density of the atmosphere affects its color. At the zenith, which is approximately 100 miles straight up, the color is a true violet-blue, but as the angle lengthens, the color changes. It becomes warmer and lighter as the air becomes more veiled with the suspended gases. 

The color gradually shifts from violet blue, to true blue, to green-blue. At sixty degrees, it becomes a yellow-green, then orange-yellow, and near the horizon, it turns into a rose-gray hue. This rose-gray hue turns darker as it approaches the horizon, transforming to a hazy warm rose-gray. The reason that it turns darker at the horizon is that the atmosphere is at its densest, and any color or light seen through it has to penetrate a thicker veil of gases. For this reason, when the sun sets, it appears to turn into a red ball.