Are you looking for new ways to make your
colors more intense and eye-catching? In that case, glazing might very well be the
technique for you and it’s definitely something you should have in your repertoire. Glazing is a technique that consists in applying
a thin layer of transparent paint over the surface. Paints can be mixed together to obtain new
colours, this is sometimes called direct mixing, but they can also be applied in layers, wet
on dry, and this is the case with the glaze technique. I already have an video about glazing on my
channel but it’s kind of old now and I wanted to have a fresh look at this fascinating technique
and investigate it more in-depth. I will try to avoid repeating myself so if
there’s something I didn’t cover in this video, it might be in the first one, so make
sure to check it out as well. History
Glazing is a very well-known technique in oil painting, in fact, it appeared at the
same time as oil painting, right when it was invented. Pioneers of oil, like Van Eyck and most of
the Northern Renaissance relied heavily on glazes for their colors, it also became very
popular in Italian Renaissance with artists like Da Vinci and Titian, who used glazes
as an essential part of their process. How come glazing imposed itself so early during
the pioneering days of oil painting ? Well, you have to realize that, back in the days,
pigments were extremely expensive. Weight per weight, the most expensive colors
were worth more than gold. And, by the way, during the Renaissance, people
were moving away from gilded background and were looking for more realistic scenes. Instead of gilding the background, artists
were asked to paint big blue skies and luxurious red robes. So, to do that, you couldn’t only use the
inexpensive earth pigments like Burnt Sienna, Yellow ochre etc. highly chromatic pigments
were required. The economy was not globalized back in the
days and the rarest pigments, like Lapis Lazuli, had to be shipped from Afghanistan at a very
high cost. So, you couldn’t waste a single ounce of
it. Now, let’s imagine that you have a small
quantity of very expensive lapis lazuli paint, or ultramarine blue as it was called (because
it had to be shipped by boat and because it was blue), and needed to paint a big blue
robe a large painting of the Virgin Mary. You had two option : 1- direct mix with the
ultramarine blue so that the entire thickness of the painted layer is made out of ultramarine
blue pigments. 2- work indirectly and start with a grisaille
to build up the bulk and the volume of the drapery, so that the thickest part would be
made only of inexpensive pigments, then let it dry and apply a very thin layer of transparent
ultramarine blue. In the end, you get a blue drapery in both
cases, but the second option drastically reduces the quantity of blue needed. Keep this in mind as this element of the cost
might explain why, when modern chemistry was invented in Europe in the nineteenth century,
when much cheaper alternatives and new alternatives could be produced, glazes started to become
less relevant for painters. For example this PB29 is a synthetic ultramarine
blue, which can be produced synthetically and doesn’t have to be mined and shipped,
since it’s much cheaper, it makes for sense to mix directly with it, and why not start
playing with thick brushstrokes, heavy impastos, just because it’s fun and it looks great
as well. This explains why artists, following the Impressionists,
like Monet, Van Gogh or Sargent didn’t use much glazing at all and were advocating for
direct mixing and for the alla prima approach. Glazing is a structural, indirect way of mixing
colors whereas the alla prima approach relies on a direct, spontaneous use of colors and
brushstrokes. Before we go further, if you want to learn
everything there is to know about color and painting, you can check my courses, you’ll
find a link in the description box. The first one, “the Practical guide to oil
painting techniques and materials” focuses on oil painting, it covers everything oil
painting related, starting with the fundamentals and exploring the more advanced techniques. My second course is heavily focused on color
theory and its applications for artists, it deals with all the complexities of color and
how to understand the more advanced techniques. Both courses got great reviews so if you want
to improve your painting skills, I’m sure they can help you a lot. Alright, let’s go back to the video. So what it glazing ?
Glazing consists in applying a thin layer of transparent paint on top of the dry painted
surface, resulting in rich, intense colors, almost like stain glass. The glaze technique requires special semi-transparent
or transparent paints. Glazes can create a unique visual impression:
they seem to appear closer than regular paint. Therefore, it is recommended to avoid them
for objects in the distance and backgrounds, on the other hand, they are very useful to
highlight a prominent subject. A glaze has a depth that makes the colors
feel more intense than direct blends. Let's take an opaque pigment, yellow ochre
(PY42) and a transparent pigment, quinacridone rose (PV19). If these two paints are mixed directly together
to form a single paste, the color of the rose dominates but the opacity of the yellow ochre
cancels out the transparency of the paste. If, on the other hand, the yellow is allowed
to dry and the rose is glazed on top, a very different optical mixture is obtained. Light goes through both layers, resulting
in a subtractive blend, much like when you place a colored filter over an image. Let's take the example of these colored filters. As you can see, they let light through, but
they filter certain wavelengths. A glaze works exactly like that. Thus, a white object glazed with red appears
red, but a blue or green object appears black (or at least very dark). Indeed, the light reflected by a green or
blue object contains no red wavelength. As a result, if blue and green wavelengths
are absorbed by the filter, no light can go through. Any filter reduces the amount of light and
therefore reduces the value. The more filters you stack on top of each
other, the less wavelengths can pass through and the closer you get to black. All this is in theory of course… it’s
important to understand how filters work, but the result of a glaze is more subtle and
more complex. No pigment can be perfectly transparent, a
small part of the light will be diffused by the upper layer, and therefore, yellow glazed
over blue has a different appearance than blue glazed over yellow. It can be seen that the order of the layers
is not interchangeable. Predicting the result of a glaze is not easy:
there are so many differences between pigments that it is impossible to predict with certainty
the final result of a glaze. The best technique is to do small tests on
small scraps of canvas or on areas of the painting that can be easily corrected. Another trick is to use a piece of glass : first
apply the glaze on the piece of glass and place it over the part of the painting you
want to glaze. This should reveal the effect of the glaze. In this example, I’m using phthalo turquoise
to glaze this red dress, the idea is to get rid of this red. A glaze can be removed, here's how to do it:
apply it to a discreet area that you are not afraid to mess up and observe the result. If the color is not what you were looking
for, use a clean, lint-free cloth to absorb the paint. Traces will surely remain visible, they will
be covered once you have found the glaze that suits you, otherwise retouch with normal opaque
paint to undo the damage. Different types of glazes
I like to differentiate two types of glazes : flat glaze and transitional glaze. First let’s talk about flat glazes. Basically, a flat glaze, like it’s name
implies, is applying a flat, uniform color layer over an relatively large surface to
modify the color significantly, for example, change a yellow dress into a green dress or
applying a red glaze over a grisaille. It can be used as a structural part of the
color construction or as a retouching technique. For example, if the color you have painted
initially is too cool for your liking, you can always apply a slightly warmer tone to
it – or, if it is too warm, apply a cool glaze. If the painting is already finished but the
contrasts seem to be too stark, a thin glaze can still be applied in order to harmonize
the colours, without covering up what you have painted. It can also be used a color boost, for example
you have an already strong blue drapery but want to make it pop even more, you can glaze
with a transparent blue. Transitional glazing is something different,
it’s much closer to the famous sfumato made famous by Leonardo Da Vinci. In this case, the function of the glaze is
not to cover the entire area but to make the transitions smoother and blend with color. In this case, the glaze is usually made of
less chromatic transparent pigments, closer to skin tones for example, like transparent
burnt umber, transparent red oxide or transparent yellow ochre. The point of this type of glaze is to boost
the chromatic presence of the object by emphasizing the soft gradation between lights and shadows. Applied over the transition, a thin glaze
reinforces the chroma very efficiently, without making the entire form too saturated. Hybrid glazes
Glazing is mostly an oil painting technique, of course, but it’s not limited to this
medium. Note that an oil glaze made can be applied
over an undercoat made of egg tempera, alkyd paints or even acrylic paints. These options will take a matter of minutes
to dry, rather than days. You can therefore start your underpainting
with acrylic and only finish with oil glazes (given that you won’t add acrylic on top
of the glaze) and with this technique, like the old masters of the past, you save on more
expansive oil paint and still have some pretty intense colors. Make sure to apply the acrylic paint in a
thin layer and wait for it to dry out completely, otherwise the oil glaze won’t work. Remember, the process doesn’t work the other
way around: you can’t apply acrylics on top of oil paints. This hybrid technique can help you mix oil
and acrylic in coherent way and will extend the appearance of the acrylic, which is normally
very mat and dry. Glazing with oil on top of acrylic is a great
option with a real sheen and depth that acrylic alone cannot allow. Application technique
You don’t need a special glazing medium to glaze successfully, I suggest that you
use the medium you normally use. However, if you want a really shiny surface
to reveal the gloss of the glaze, you can try this one: 2 parts Venice turpentine +
4 parts linseed stand oil + 9 parts dammar varnish + 9 parts turpentine
Again, I still suggest to use a regular medium to glaze, the most important part is not the
medium but the transparent pigment. Not all paints can be glazed, opaque paints
will not work, even with a glazing medium. The glaze technique requires a careful approach
and it cannot always be applied. It is a method that really makes the colours
stand out. Semi-opaque glaze
If you replace transparent pigments with semi-opaque or opaque pigments, you don’t technically
get a glaze but what I call a “velatura”. This technique is applied exactly like a glaze
but gives a less intense result. Due to the fact that it’s not perfectly
transparent it’s similar to what could be achieved by direct mixing. It is a technique that can be interesting
to modify shadows on a portrait, or create very smooth transitions between shadows and
lights, in the same way as the sfumato, introduced by Leonardo da Vinci. Thank you very for watching this video, again
a huge thank you to my Patreon members, this video wouldn’t be possible without your
support. If you want to join the community, you will
find a link in the description below. You will also find the link to both my courses,
my oil painting course and my color course. Glazing is covered in depth in both and demonstrated
in multiple painting situations, portrait, still life and landscape.
