Luminous Glazes in Oil
Create works that radiate light with multiple layers of transparent paint.
By Arleta Pech
Do you love the luminosity of stained glass? Then you’ll be happy to know that you can achieve clear, glowing colors in your oil paintings with multiple transparent glazes. These radiant layers give objects depth and form, so they seem to lift off the painting surface.
I created Summer Splendor (above) and Red Wine Decanter (at bottom) with thin applications of oil paint mixed with glazing medium in a process called optical glazing. The term describes how the eye perceives light moving through layers of transparent colors, translating those colors into a final hue.
The key to this technique is knowing when to use transparent, semitransparent, semiopaque and opaque paints. Each has a different effect on the luminosity of your subject. But first, you need to determine the opacity or transparency (coverage) of your colors. Here’s how: Paint a black stripe on a scrap piece of board. After the paint dries, use a glazing medium to thin your favorite colors into a medium value and then glaze each one over the black stripe onto the white board. If the color disappears or is very light on the black, it has some level of transparency. On the other hand, the more the color shows on top of the black, the more opaque it is. (See Coverage Test, below.) Be aware that from paint brand to paint brand, colors with the same names have different covering powers.
Once you’re familiar with the coverage of your colors, you’re ready to start glazing. The following demonstration explains how I used this technique on Red Wine Decanter.
1. Start with the lightest values
Looking at the finished roses closely, you can see the layers of colors that make their red hue. Glazing those colors in the right order is key. Because you work from light to dark in oil, I looked for the lightest color that I could see in the roses—a pink glow under the red and near the highlights. I chose permanent rose for my first glaze. If the roses had shown a warm orange glow, I’d have chosen a yellow glaze to start. Once the first glaze was dry, I could apply the second. The color of the second layer should be the next value up in the subject; I chose quinacridone red. The same process and colors were used for the wine.
I started the leaves with sap green and Indian yellow in a blended glaze. For the glass and silver, I started with the lightest value of gray, which I mixed from transparent colors of ultramarine blue (green shade), burnt sienna and a tiny touch of alizarin blue lake. The white areas of canvas were left for the whites in each object. I knew that if, toward the end of the painting, these areas seemed too bright, I could tone them down with a glaze.
2. Add warm and cool areas
It’s fun to add cool or warm glazes to deepen values or create special areas that glow. I used semi-transparent Winsor orange to add a warm glow to the lower right corner of the wine and a glaze of alizarin blue lake on top of the wine for a reflected color bounce from the white wall. Notice that in these two areas, there are still parts of the first two glazes showing. If you totally cover the previous glazes each time you add a glaze, you’ll flatten the object, but letting some of the previous glaze show builds form and deepens value.
3. Build deeper values
To build deeper values, select transparent colors with more power, such as the permanent alizarin crimson I used on the roses. This cooler color, which deepened the value of the flower’s crevices, was actually glaze number five on the roses, and each glaze slightly affected the flowers’ hue. Before they’re finished, the roses will have acquired 10 glazes. The value structure that each glaze creates and the luminosity those glazes achieve result in a very different, more realistic look than that of a work painted with an impressionistic opaque process.
For the wine decanter and the leaves, alizarin blue lake is the more powerful and cooler color that adds value and depth.
4. Apply reflected colors
There are no set glazing mixtures for painting silver because reflected objects around the silver alter its color. Accordingly, I had started the silver with a transparent gray glaze to establish its form. I then chose subsequent glazes based on surrounding reflected objects, giving the silver sparkle and color bounce. When I was ready to place the darks, I mixed a transparent black with alizarin crimson, sap green and alizarin blue lake. With those three colors I can create red black, green black or blue black simply by adjusting the mixture.
5. Take care with semitransparents
There are times when you need to alter an object or pull it together with a large glaze. I wanted the rose highlights to have an orange-red glow, and the shadow side of the roses needed more depth. I knew I would have to give up most of the pink glaze that I had worked to save. I chose a semitransparent bright red for a thin glaze across most of the rose petals.
Be careful with semitransparent glazes; too heavy a layer will destroy the glow you’ve been building. Hold off on this glaze until you have good values in three to four other glazes, so that the form of your subject (in my case, the roses) holds. Once you bring a semitransparent color into your painting, place it in at least three areas to move the eye through the painting. For this reason, I also added my semitransparent color to the wine and as a very thin glaze in tiny areas on the silver.
6. Make adjustments
The semitransparent glaze dulled the darks in my roses, so I used a mixture of alizarin crimson and sap green with a touch of alizarin blue lake for a very dark red black to place the darkest darks in the roses. The leaves underwent many alternating glazes, but the final glaze was a transparent dark green mixture of sap green, alizarin crimson and alizarin blue lake.
7. Touch up with opaque white
Can you use opaque color in a painting created with transparent glazes? The only absolute rule in art is to paint your vision and use whatever you need to do so. I prefer to leave out mixed opaque colors because they tend to look like adhesive bandages over transparent glazes. But in Red Wine Decanter, I did use titanium white to clean up the edges of my whitest highlights and to add a few tiny sparkles that I had lost in the wine. Also, the background cast shadow looked too deep, so I toned it to a softer hue with a very thin glaze of milky titanium white.
Painter and workshop instructor Arleta Pech (www.arletapech.com) is the author of the North Light book Radiant Oils: Glazing Techniques for Paintings that Glow.
This article appeared in the June 2009 issue of The Artist’s Magazine, which is available for order as a digital download. Click here to learn more.
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