Glazes are distinguished notably by their firing temperature, finish, composition, and form. Some are offered ready to use in liquid form, while others are available as powder to prepare yourself. In addition, there are numerous ranges and brands, each offering its own colors, effects, and specificities.
In this article, we invite you to discover the main types of ceramic glazes to better understand their differences and choose the products best suited to your creations.
What is a ceramic glaze?
A ceramic glaze is a vitrifiable layer applied to the surface of a piece before a new firing. Under the effect of heat, the different components of the glaze melt and then, upon cooling, form a vitrified surface that can be shiny, matte, smooth, or textured.
The glaze therefore plays a major aesthetic role, as it allows you to add color and different effects to a creation. It also has a technical function: depending on its formulation and use, it can make the surface less porous and easier to clean.
However, the final result depends on many parameters. The nature of the clay, the firing temperature, the thickness of application, the number of layers, the atmosphere of the kiln, or even the combination of several glazes can considerably change the final appearance. The same reference can thus show different shades depending on the conditions under which it is used.
Glazes for earthenware: working at low temperatures
Earthenware glazes are generally intended for low-temperature firings. They allow you to achieve a very wide variety of colors, notably bright shades and shiny surfaces that are particularly popular for decorative objects and tableware.
Since earthenware is porous after its first firing, glazing creates a vitrified surface. Depending on the desired effect, you can choose a transparent glaze to reveal the color of the clay or a design made with underglazes, or opt for an opaque colored glaze.
The ranges intended for earthenware are particularly interesting for potters looking for a wide palette of colors and a relatively accessible application. However, it remains essential to respect the firing range indicated by the manufacturer to achieve the expected result.
Glazes for stoneware: resistance and rich effects
Stoneware glazes are designed to be fired at higher temperatures. They are particularly appreciated for their depth and the diversity of their effects. Depending on the formulations, they can produce shiny, satin, or matte surfaces, as well as mottled, crystallized, metallic, or highly reactive results.
Stoneware offers a particularly interesting medium for experimentation. Some glazes change appearance significantly depending on the clay used. The same product applied to white, beige, red, or black stoneware can produce very different results.
Layering is also a widely used technique. By applying two compatible glazes on top of each other, it is possible to create new shades, drips, and effects of depth. This practice nevertheless requires some precautions, as some combinations can become very fluid during firing.
Raku glazes: unique effects
Raku glazes are specially designed for Raku firing, a technique characterized by removing the pieces while they are still glowing hot, generally followed by a smoking and reduction phase. This process allows you to achieve unique and often unpredictable results.
Depending on the glaze and firing conditions, the surfaces can show metallic, copper, iridescent, matte, or shiny effects, as well as color variations and characteristic crazing. Smoke can penetrate these cracks and make them stand out, while blackening the areas left without glaze.
Raku requires a clay, glazes, and equipment suited to the significant thermal shocks. This technique is mainly intended for decorative pieces and is generally not recommended for tableware or food contact.
Transparent, opaque, and colored glazes
Beyond the firing temperature, glazes can be classified according to their opacity. A transparent glaze allows the color of the clay or a design made under the glaze to remain visible. It is therefore particularly suited to protecting and highlighting underglazes, overglazes, or other designs.
Conversely, an opaque glaze masks the support more and brings its own color to the piece. This opacity allows you to achieve more uniform surfaces and can be interesting when you want the color of the glaze to completely dominate that of the clay.
Between these two extremes, there are also many semi-transparent glazes or those showing variations in opacity. A thin layer can reveal the support, while a more generous application produces a more opaque result.
Shiny, matte, and satin glazes: what is the difference?
The finish plays an essential role in the final appearance of a ceramic piece. Shiny glazes reflect light strongly and generally give colors a more intense appearance. They are particularly common on tableware and decorative pieces.
Matte glazes, on the contrary, produce a much softer visual surface, with little or no light reflection. They are particularly appreciated in contemporary ceramics for their natural and mineral appearance.
Between the two, satin glazes offer an interesting compromise. Their surface shows a slight reflection while maintaining a softer feel and appearance than a very shiny glaze.
The choice between matte, satin, and shiny is primarily aesthetic, but you must also take into account the final use of the piece and the manufacturer's recommendations, especially for creations intended for food use.
Reactive glazes: unique results after firing
Reactive glazes are formulated to produce variations during firing. They can reveal several shades, create drip effects, make areas appear lighter or darker, or react differently on the reliefs of the piece.
These glazes are particularly interesting on textured surfaces. On a piece with hollows, engravings, or reliefs, the glaze can accumulate in certain places and become thinner on the protruding parts, naturally creating contrasts.
This richness also implies a degree of unpredictability. The thickness, the clay, the actual temperature reached by the kiln, and the firing cycle can change the result. It is therefore advisable to perform tests on test pieces before using a new glaze on an important piece.
Effect glazes: crystals, textures, and variations
Some ranges go even further by incorporating elements intended to produce specific effects during firing. Crystal glazes, for example, contain particles that melt and spread across the surface of the piece, creating spots, halos, and color variations.
Other references allow you to achieve textured, mottled, or stone-like surfaces. These products are particularly appreciated for quickly creating complex designs without having to multiply techniques.
Since the result is directly linked to the melting of the glaze, it is important to follow the manufacturer's recommendations regarding thickness and temperature. Some effect glazes, in particular, can become very fluid during firing.
Liquid glaze or powdered glaze: which form to choose?
Liquid glaze ready to use is probably the most accessible form. The product already has a consistency suitable for application and can generally be used directly after being carefully mixed. It is particularly practical for application with a brush and is suitable for both beginners and potters wishing to work with small quantities or multiply colors.
Powdered glaze requires more preparation. It must be mixed with water in the appropriate proportions, then generally sieved before use. The preparation can then be adjusted according to the desired application method.
This form is particularly interesting for workshops using large quantities of glaze. It also allows you to more precisely control certain preparation parameters and is well suited to techniques such as dipping, pouring, or, with the appropriate equipment and precautions, spraying.
There is therefore no form that is systematically better than the other. The choice depends essentially on the production volume, the application method, and the level of control desired.
The different ways to apply a glaze
The brush remains one of the most common methods, especially with ready-to-use liquid glazes. Several layers are generally necessary to achieve the thickness recommended by the manufacturer. The direction of application can be alternated between layers to achieve a more even surface.
Dipping consists of briefly immersing the piece in a glaze bath. This technique is particularly suited to workshops and allows you to quickly obtain a relatively homogeneous layer over the entire piece.
Pouring, on the other hand, can be used to glaze the inside of certain shapes or deliberately create drip effects. Finally, spraying allows you to obtain thin and gradual layers, but requires suitable equipment as well as appropriate protective measures.
The application method directly influences the deposited thickness and therefore the result after firing. A glaze that is too thin may lack intensity, while an excessive layer can lead to drips or other defects.
Pencils, chalks, and other forms of ceramic decoration
Decorating a piece does not only involve traditional glazes. There are also pencils, chalks, underglazes, and overglazes that allow you to draw, write, or create designs before the possible application of a transparent glaze.
These products open up many creative possibilities. They allow you, in particular, to work with greater precision than a classic glaze and to combine drawing, color, and surface effects on the same creation.
However, they should not all be considered glazes in the strict sense. Their function, their application method, and their behavior during firing are different. It is therefore important to check their compatibility with the clay, the eventual covering glaze, and the planned firing temperature.
The main brands of ceramic glazes
The ceramic glaze market includes several specialized manufacturers, each offering ranges with different characteristics. At Ceradel, the choice of a glaze can thus be made based on the desired firing temperature, the desired type of effect, and application habits.
MAYCO offers a very wide choice of decoration products and ceramic glazes. The brand is notably known for the diversity of its colors and effects, with ranges allowing you to work on both relatively uniform surfaces and more complex and reactive results.
AMACO is also an essential reference, particularly appreciated for its stoneware glazes and its numerous layering possibilities. Some ranges allow you to achieve very rich effects when several references are combined, making it a particularly interesting brand for experimentation.
BOTZ offers ready-to-use glazes appreciated for their ease of use and the diversity of their results. The brand has solutions suited to different temperature ranges as well as references offering particularly interesting effects on stoneware.
Spectrum completes this diversity with many colors and glaze ranges, notably reactive and textured references. These products allow you to achieve surface variations that can change significantly depending on the clay and firing conditions.
These different brands should not only be compared based on the color visible in a color chart. The recommended temperature, the number of layers, the type of clay used, and the expected result must also be taken into account when choosing.
Can you mix or layer different glazes?
Layering glazes is an excellent way to expand creative possibilities. Two relatively simple colors used separately can produce a completely different result when applied on top of each other.
However, the behavior of a combination is not always easy to predict. Some glazes become more fluid when layered and can drip down to the kiln shelf. The reactions between two formulations can also change the color, texture, or shine.
To experiment without risking an important piece, the ideal is to create your own test pieces. You can then note the clay used, the glaze references, the number of layers, and the firing temperature. Over time, these samples constitute a real library of colors and combinations unique to each workshop.
How to choose your ceramic glaze?
Before choosing a color, you must first check the technical compatibility of the product with your clay and firing temperature. A glaze intended for a low-temperature firing should not be used as a high-temperature stoneware glaze without specific indication from the manufacturer.
You must then determine the desired result. To keep a design or the color of the support visible, a transparent will generally be preferred. To obtain an opaque color, you will lean more towards an opaque glaze. For a more lively and variable surface, reactive, textured, or crystal glazes offer many possibilities.
The form of the product must also match your practice. For a few pieces and application with a brush, ready-to-use liquid glazes are particularly practical. For a workshop using large quantities or working mainly by dipping, powdered glazes may be more suitable.
Finally, it is always recommended to perform tests. In ceramics, a color presented on a color chart or screen remains indicative: the clay, the application, and the firing are an integral part of the result.
Find the glaze suited to your creations
From uniform colors to reactive surfaces, from matte finishes to intense shine, the world of glazes offers immense creative freedom. Understanding the differences between firing temperatures, finishes, forms, and application methods allows you to more easily choose the products suited to each project.
Ceradel offers a wide selection of glazes and decoration products to accompany both initial experiments and the needs of professional workshops. MAYCO, AMACO, BOTZ, Spectrum, and other ranges allow you to explore a multitude of colors, textures, and effects to personalize each creation.
Regardless of the range you choose, the best way to master an enamel is through experimentation. A few shards, different thicknesses, and various combinations often reveal unexpected results and help you gradually develop your own palette.
