Glaze Color Tests

For our company’s Product Design Offsite this year, we conducted a remote-first virtual autonomous offsite with a focus on learning aspects related to our practice as Product Designers.

During this period, I took a day off to delve into the realm of glazes and the development of a color system similar to a design system. Pottery glazing is considered tricky for several reasons and necessitates a bit of experimentation. Some key challenges include:

• Consistency: Achieving consistent results with glazes can be challenging due to variations in ingredients, application methods, and firing conditions. Small changes in any of these factors can lead to significantly different outcomes.
• Color Transformation during Firing: Glazes often undergo chemical transformations during the firing process. Colors that appear one way before firing may change unexpectedly, making it difficult to predict the final result.
• Chemical Interactions: The interaction of different glaze materials can be complex. The combination of minerals and oxides in the glaze recipe can produce unpredictable reactions, influencing the color, texture, and surface quality of the finished piece.
• Application Techniques: The way glazes are applied plays a crucial role. Factors such as thickness, layering, and brushstroke techniques can affect the final appearance. Achieving an even coat without drips or uneven patches requires skill and precision.
• Kiln Firing Variability: The kiln firing process introduces additional variables. Factors like temperature, firing duration, and the atmosphere inside the kiln (oxidation or reduction) can all impact the final look of the glaze.
• Understanding Raw Materials: Knowing the characteristics of various raw materials used in glaze formulations is essential. Different clays, feldspars, oxides, and other ingredients can behave uniquely, and mastering their interactions is crucial for successful glazing.
• Trial and Error: Due to the intricate nature of glazing, artists often rely on a process of trial and error. Experimentation with different glaze recipes and adjustments based on the outcomes is common practice.

Similar to the colors in light versus dark mode, different clay bodies can cause the glaze to appear different. The image below shows the same glazes on three different color clays (reference photos from Mayco and Amaco catalogs), revealing significant variation between them.

Layering glazes in different orders or combinations can result in a wide range of surface variations, such as subtle color shifts, textured surfaces, crystalline formations, or other visually appealing outcomes. The image below displays my glazes on the left side and the manufacturer’s photos on the right, highlighting significant variations in color and texture between both the single glaze and the glaze combination.

The appearance of glaze combinations can vary depending on which glaze is applied on top versus the bottom due to several factors, including the interaction of different glaze materials and their melting and flowing behavior during the firing process (reference photos from Mayco and Amaco catalogs).

The photo below showcases the glazing process, illustrating how different the glaze looks before and after firing.

After testing about 60 different glazes and combinations, I compiled a chart visually comparing the manufacturer’s glaze photo and those from my own tests. The blank spots indicate combinations I created without any reference. Considerable variation in some of these tests emphasized the importance of this process (reference photos from Mayco and Amaco catalogs).

The chart I developed below helps me see visually and economically which glazes have the most combinations that I like. The top row represents the glaze used on top, and the side column represents the glaze used on the bottom. The reference photos are the first column.

Finally, here are the results tested on a few pieces of pottery I threw earlier. I used three coats per glaze (six if it was a glaze combination). Overall, I am quite pleased with these tests and hope to continue experimenting with more combinations.