How to Mix Oil Colors – Optical Mixing Effects

Art Lesson 21, Part 2

Discover How to Mix Oil Colors – Optical Mixing Effects

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How to Mix Oil Colors – Optical Mixing Effects

Let’s proceed with the next section of Mixing methods – Optical mixing methods. This is the more sophisticated technique, therefore creating even more interesting results.

We have already covered some of the Optical mixing methods, like transparent Glazing and semi-transparent Velaturas, in previous Video Lessons.

When we apply Glazes and Velaturas layers, the underneath layers of paint show through, creating a complex and completely different Hue and tone.

For that exercise, we already applied a first layer of Red Paint. It will play a role of an Underpainting. Note that it is absolutely dry, as it should be in multi-layered painting.

In this first cell, we will apply classical transparent Glazes. When applied over a white background, we see the Color of the thinned Paint as it is. While over-painted the Red Underpainting, these Glazes fall under the influence of the underlying layer. When we do Glazes, we obligatorily need to add an appropriate Medium (Stand Linseed Oil, for example) to the Paint to make it transparent.

When we choose for Glazing purposes such Paints that are lighter than the Paint which we are going to glaze over – we will get another kind of Glaze – that creates a turbid, cloudy effect and makes the Tone lighter. We call such Glazes with a special, more precise term “Velaturas” – that means “Veiling” in Italian. Needless to say, we also have to thin the Paint with a Glaze Medium, as in the case of transparent Glazing.

Just note the differences that Glazings make in this example. Apart from changing the Color, it also changed the Tone, making it darker. But coming back to opaque Glazings, or Velaturas, as you can call them – the tonality becomes lighter. Velaturas are mostly appropriate in the painting of flesh.

Now, one more Optical Mixing method – Scumbling. The very process of applying Scumbling layers, as well as the final visual result, differs from Velaturas. First of all, the Scumbling method requires a stiff-hair Brush, like a Hog Brush, for example. Needless to say, but I’ll remind you just in case – the previous layer should be well-dried before applying the Scumbling layer. With a stiff, rigid brush, we need to rub the Paint into the Canvas. You see that we used a “Dry Brush” technique, which means we had very little paint on the Brush. This is a key-point of Scumbling. If you take too much Paint with the Brush, just remove the excess Paint with a piece of cloth; the Brush should be almost dry. And, of course, no Mediums or Diluents are added. Use pure Oil Paint from the tube.

This method is ideal when Scumbling layers are done with Lighter Colors over a Darker Under-Painting. We see here how the Red Color shows through the Scumbling, creating an Optical effect, which is exactly what we wanted.

The last method is Sgraffito. The name is borrowed from a monumental wall decoration method. The word itself translates from Italian as “to scratch”. In Oil Painting, this method is especially impressive when Sgraffitos are applied over an Underpainting made as Impasto. When our Red Underpainting becomes dry, we apply a new layer of Paint of a different Color. With this method, you can thin or dilute the Paint however you want, or apply the tube Paint. Then, while the upper layer of Paint is wet, you can use the handle of the Brush to scrape across the wet Paint, laying open the Color of a previous layer. A Palette Knife can also be used.

As an alternative, you can sandpaper the upper layer of Paint when it’s dried to reveal the Colors underneath. Both ways end up in an Optical effect that can’t be created Mechanically.

Let’s summarize what we have discussed here and what conclusions we can make looking at these exercises.

Both Mechanical and Optical mixing of Colors are equally important in the Old Masters’ paintings.

This upper part of Mechanically/Physically Mixed Paints represents the methods that could be used by us. They very effective in the preliminary stages of the painting process, up to the Underpainting or Underglazing stages. In other words, the whole painting should be completed by Mechanical painting, till we proceed with finishing layers using Optical methods, which are more flexible and rich in visual language, in visual effects. This Mechanical stage could be compared to a constructed building that later needs to be decorated.

Old Masters are known for their multi-layered painting methods. They mix Paints on a Palette before applying them to a Canvas. But within their complex, multi-layered artwork they could insert a passages created exactly in this Wet on Wet method, mixing Paints right on the Canvas. For example, the hair of a model could be done in such a way, while the model itself could be created by an elaborate combination of Glazes and Velaturas painted over a Mechanical Underglazing.

Contemporary Painting techniques rarely go beyond Mechanical Mixing. I tell you more – after the 17th century, the Golden era of Old Masters, with their brilliantly executed masterpieces, were replaced with a less sophisticated mechanical approach.

With time, the culture of dual importance of the physical and visual quality of an artwork and its meaningful contents shifted towards the domination of Idea over the visual quality of the painted surface. Today WHAT is more important than HOW.

Let’s return to the Mechanical Mixing examples. Why did we include Pointillism here, despite the fact that it has all the characteristics of Optical layer? First of all, it doesn’t require any cooperation with the underlying layers, and it doesn’t depend on the Underpainting. It could be done in Alla Prima. This diagram illustrates what I’m talking about: in Mechanically Mixed Paint, we create one dense layer, containing particles of Pigment of different Colors. Here, we have Blue and Yellow Color particles intermixed into Green Color.

The Optical method requires the layering of different types of transparency over a specially prepared Underglazing. On the diagram, we see the Blue Underglazing and a thin layer of Yellow Glazing on the top.

The Optical effect can’t be achieved by Mechanically Mixed Paint. This sophisticated, rich, polyphonic effect was highly appreciated by the Old Masters, and they paid much attention to creating it. It’s a mistake to think that the Masters achieved those visual results accidentally. It was a carefully calculated system of layering a complex surface texture, formed by the Underpainting and following Optical layers. Glazings are highly dependent on the Underglazing you prepared for them. An Underglazing should always be lighter and colder, as upper Glazings will make lower layers darker and warmer, anyway.

To summarize what Optical Mixing requires: it is not an independent coat of paint. It works only in collaboration with an appropriate Background. You have to have prepared the Underpainting and let it dry completely. In case you apply the Glazings over an Underpainting that is freshly painted, or half-dried, your Paint will just mix with the Underpainting – that, first of all, violates the technical requirements of multi-layered painting, which state that each layer should be thoroughly dried before applying next one. And secondly, there will no be any Optical effect achieved. The glaze layer and the Underpainting will just be physically mixed together.

Optical effects created by Glazing affect the color perception of the painting surface. They play a bigger role than you might suppose. For example, let’s take some of Rembrandt’s masterpieces, “the Jewish Bride,” for instance. What we see on a painting – those emotions we are immersed into, the characters’ poses and facial expressions, the position of the hands – everything fascinates us enormously. I have seen the painting many times, and every time, I felt that I was in contact with something Huge, Noble and Magnificent; something not real, and definitely not done by human hand. But, just believe me, we wouldn’t feel half of those emotions if the painting had been painted in a Direct, Mechanical manner, by Physically mixed Colors.

Rembrandt’s ability to render the Color optically made the painting surface rich and deep; that makes “the Jewish Bride” a masterpiece. Without that polyphonic music of glazed layers, this painting would be average. This superb quality of the surface, it’s fantastic complexity, even can excuse an awkward anatomy in the woman’s arms and shoulders. It’s so secondary, so unimportant; what is really making us exited – is Rembrandt’s light that comes from inside of the painting. And this light could be done only through Optical Mixing.

So, we have to learn how to master this knowledge and turn it to the good in our art, as the Old Masters did in their painting.

What you need for the task:

• Worksheet #11
• Prepared Support – Canvas, Canvas Board or Oil Painting Paper A3
• Masking Tape
• Some Colors, for example any Red and any Yellow
• Hog or/and Synthetic Brushes
• Palette Knife
• Liquin Original