Gesso is a primer which acts as a barrier between the material you are painting on and the paint itself. Most Acrylic Gesso is useable for both acrylics and oils, but there is also a traditional gesso that many oils painters prefer.
There are many brands of gesso out there. I would like to discuss some of the brands I have worked with.
I'll explain a little bit about the properties and uses of each of them. I am not endorsing any particular brand, but just writing from my experience.
I'll focus on acrylic gesso to start since that is the one I am most familiar with.
Most of the brands on the market have a white gesso.
It is generally a flexible liquid which seals the material it is painted on whether it be canvas, paper, or wood, etc. Once dry, a canvas with several thin coats of acrylic gesso is flexible enough to be rolled up without cracking.
If thicker coats are applied, the chance of cracking increases.
If you check the label of the brand you use, it will state what media it can be used for. Most of the brands stated that they were good for acrylics and oils.
I don't do oils any more because of allergies and asthma which were bothered by the paint fumes and solvents of regular oils. I do use water soluble oils, however, and the acrylic gesso works very well under them.
Also on some, but not all of the labels, you will find information about how to dilute the gesso, temperature considerations and number of layers to apply.
When you have a question about a particular gesso, and the label does not answer your question, go to the manufacturer web sites. They frequently have really good information for you. This is not so with all brands, however.
If you go to the Golden Paints web site, it will tell you that you can tint the white gesso, but recommends that you use a small amount of heavy load acrylics since they closely resemble the gesso which also has a high pigment load.
It tells you that the white gesso is made from PW6. If you are not familiar with this coding, the "P" stands for pigment as opposed to "D" which stands for dye. The "W6" is the code for the white that is used. Generally pigment paints are better than paints using dye.
Golden also recommends that if you are using the gesso under oil paints, you should use three coats to prevent the oil from penetrating the surface you are painting on. You must let each layer dry completely before applying the next coat.
This brings up the question of how long it takes a layer to dry. According to Golden paints, their gesso, when put on as a very thin coat (10 mil), will dry in 2 hours if the temperature is above 65 degrees.
Factors which will increase drying time are:
I usually wait several hours in between or sometimes even wait until the next day.
They also recommend that you do not freeze acrylics.
If you feel the need to sand the gesso, check with the individual manufacturers. Golden Paints state that their white gesso can be sanded, but recommend that you use a wet sanding technique. This avoids excessive dust from sanding and stops the sandpaper from getting clogged up.
Pretty much everything about the black gesso is the same as the white, except that, in Golden's case, the coding is PBk11
The black gesso creates a very interesting background for certain paintings.
This painting was part of a monthly challenge I did on the Water Soluble Oils Forum which I am a member of.
It was based on a photograph by Steve Evans on Flickr called "Ginger"
Here is an other example of a painting I did on a black gesso background.
It was just a test on canvas paper to see if I liked working on black.
It also gave me a chance to see if I could do a transparent glass, something I had never done.
Excuse the brightness on the bottom. It was from a glare during the photographing process, not how I painted it.
I haven't done any real paintings using the black gesso, only practice ones, but I definitely like it and plan on doing a large painting with it soon.
In both of these paintings, I used water soluble oils and they adhered very well. The black does have a matte finish so if I did a large painting in water-soluble oils, I would probably coat it with a very thin layer of walnut oils before starting to paint.
This would bring up a semi gloss finish and would also enhance the bonding of the water soluble oils to the acrylics, a hint I learned form Jerry Yarnell in one of his educational videos.
There are times when you don't want gesso to show, but you do want to seal a surface for painting.
Liquitex and a clear gesso which I am very happy with. It is great for sealing wood projects I do where I want some of the wood grain to show through.
The clear gesso gives high tooth to the painting surface. The high tooth makes the paint adhere very well.
Liquitex states that because of the tooth, you can apply acrylics, oils, water soluble oils, pastels, oil pastels, graphite and charcoal.
I think it would be fun to try using it under pastels on a rigid surface that you wouldn't usually do your pastels on. The applications are unlimited.
I frequently make plaques on wood and usually use acrylics to do the painting. Here is an example of one I did using water soluble oils.
As usual, I was experimenting to see if the clear gesso would seal the wood sufficiently to be able to use water soluble oils on the wood without the oil penetrating it.
Liquitex recommends that you apply 3 thin coats when using oil. I had no problem with the water soluble oil adhering to the wood, and there was no penetration of the oil.
If you are curious about the letters on this plague, go to Acrylic Transfers, a page I have written on creating acrylic transfers from your computer to use for projects like this one.
Some other information Liquitex gives you on their web site is that:
According to Liquitex, their clear gesso can be tinted, but they recommend that you only ise small amounts of transparent or translucent acrylics. This will help maintain the transparency.
In researching gesso, I also came across a company that produces a gesso specifically for rigid surfaces or surfaces that you would like to make more rigid.
According to the Art Board web site, they produce a gesso that is not like the the other three gesso products I have talked about. It does not have the flexibility of the other ones. It is actually designed to make flexible surfaces more rigid
The thing I found interesting about it is that they say it can be used for "oils, acrylics, egg tempera, casein, gouache, watercolor, encaustics, pastels, charcoal, colored pencil, silver point, pen & ink, air brush and more.
I have not tried this product yet, but I could see where it would open up a wide variety of opportunities to paint or draw on surfaces that are not always the traditional ones.
I will expand on this form of gesso, if I get a chance to experiment with it.
So far all of the gesso products I have discussed were able to be used for many different art media. There is a gesso made specifically for oils and is the traditional one used by oil painters.
The traditional gesso is made from a powdered mixture of gypsum, rabbit skin glue, marble dust, and titanium white.
I have neve used it, but I did find information on it in the Gamblin website and the Fredrix website.
Here are some gesso tips you might be interested in.
I'm sure there are a lot more possibilities for using gesso as something more than just a primer. Experiment with it and be pleasantly surprised.