An Introduction to Spectrum Underglazes for Ceramics

Not quite a glaze and not quite a slip, underglazes allow you to color your work without worrying about how it will look after firing. It’s easier to control than overglazing as well, and the results will often match what you see unfired.

Spectrum’s 500 Series underglaze colors are all lead free, dinnerware safe and A/P non toxic when covered with a clear glaze. They are usable at nearly any temperature range and can be applied to leather hard greenware or bisque.

Basic Ingredients

Underglazes are paints that are applied to a ceramic surface before it is covered with a transparent glaze and fired in the kiln. They can have a velvet-like matte finish when used without a glaze or they can be made glossy by applying a clear glaze over them. They are made with pigments derived from oxides.

Underglazing is a decorative technique that allows for intricate brushwork and patterns on the surface of your ceramics. It is a way to create a surface decoration that is food safe and durable when covered with a clear glaze. Essential pottery supplies like this underglazes, are available in a wide range of colors and can be mixed with each other or with other underglazes to achieve varying intensities of color and transparency. Underglazes are lead free, non-toxic and dinnerware safe when covered by a dinnerware safe clear glaze

Unlike pure clay body stains, underglazes do not bond with the pottery surfaces they are painted on. They are formulated into a recipe of materials with a base medium to impart the necessary properties to be compatible with a variety of clay bodies. Commercial underglazes contain a variety of additives to keep frit and stain suspended and to make the underglaze paintable.

These orange underglazes on this bowl were not properly fluxed (melted) so that they adhere to the body. This is a common problem with many commercial underglazes. The underglaze also has a high gum content that seals the surface of the bisque and inhibits its ability to pull in glaze water during dipping. These slow absorption rates cause the underglaze to dry with a rough, flaky surface that can generate bare spots. The solution is to decorate ware in the leather hard or dry (bisque) state or to use an underglaze that has a lower gum content.


Whether you are creating intricate details on a functional mug, painting a landscape on a decorative vase or exploring abstract patterns on a sculptural piece, underglazes allow you to express your artistic identity with each brushstroke. As a slip or pigment, spectrum underglazes can be applied in a variety of ways including brushing, dipping and spraying, and they can be covered with transparent glazes or left unglazed for an organic textured surface.

To make underglazes you will need to combine frit, kaolin, silica and metal oxides in the proportions specified by the color recipe. Mix dry ingredients together thoroughly and then add water slowly while continuously mixing until a smooth slurry consistency is achieved. Use a ball mill or mortar and pestle for smaller batch sizes to ensure that the particles are well dispersed.

Pure ceramic stain powders don’t melt at typical pottery temperatures and do not bond with clay body surfaces. This is why underglaze manufacturers dilute the stains with a medium, a ‘base glaze’, to impart these properties.

To create a high-fired underglaze you will need to incorporate high percentages of stain. These diluted colors are very bright and very expensive to produce, which is why commercial underglazes are often double or triple the cost of a comparable transparent glaze from the same manufacturer. The top mug on the left was painted with V-326 underglaze and the bottom mug with Amaco LG-10 underglaze, both glazed and fired at cone 04. Both are dinnerware safe when covered with a clear glaze.


Whether you are brushing, dipping, or spraying your ceramic creations, you can add intricate patterns and vibrant color with underglazes. These underglazes are essentially colored slips or pigments that are applied to greenware or bisqueware before the final glaze firing. The underglazes are easily applied using a wide variety of methods such as painting, brushing, and sgraffito techniques.

Before you begin creating your underglazes, prepare your workspace by setting out your raw materials and equipment in a well-ventilated area. Always wear appropriate safety gear when working with raw materials and mixing chemicals. Read and follow all instructions provided by your manufacturer when handling and mixing your ingredients.

The preparation of your underglazes can take several days, so be sure to plan ahead! Once you have mixed your colors and created a consistent consistency, store them in airtight containers. It is a good idea to conduct test firings with your underglazes before applying them to your work to ensure the best results.

Spectrum offers a full palette of rich, vibrant colors that are opaque with 3 coats, semi-opaque with 2 coats and semi-transparent with 1 coat. These underglazes are lead free, dinnerware safe and A/P non-toxic when covered with a dinnerware safe clear glaze. They can be applied to greenware, bisque and raw clay and fired at nearly any temperature range.


Underglaze colors look very different before firing than they do after. This is one of the biggest challenges with brush decorated pottery because it can be difficult to see what the decoration will actually look like until after the kiln fires and the glaze covers it.

Commercial underglazes mix stains with a recipe of materials to give them ceramic properties. Pure stains do not melt at typical pottery temperatures so they can’t bond with clay body surfaces. This causes problems when the stains are too potent or not mixed properly.

Spectrum 500 series underglazes are lead free, dinnerware safe and A/P non-toxic when covered with a clear glaze. These underglazes can be applied to a dry bisque or greenware. They are designed for use at a wide temperature range and can be used on oxidation or reduction fired clay bodies.

Spectrum’s 600 series one-stroke underglazes are a more concentrated version of the underglazes in the 500 series. They are designed to provide opaque coverage with a single brush stroke and they work great under our Glossy and Milky Clear cone 6 mid-range glaze recipes. These underglazes are also dinnerware safe when covered with a clear glaze that is compatible with your firing temperature.


Top 10 Benefits of Hiring a Commercial Cleaning Service for Your Office

Dirty areas in your office are a breeding ground for germs and bacteria that can lead to illness. A Commercial cleaning in Melbourne can help keep your workspaces clean and healthy.

A clean workplace can save you money in the long run by reducing employee sick days. It also gives employees more time to focus on important work tasks.

1. Saves You Time

When you hire a commercial cleaning service, they can save you a lot of time. Instead of having your employees spend their time on cleaning, they can focus on important company tasks and making money for you.

It can be difficult to fit cleaning your office into a busy schedule, so it often gets overlooked or put on the back burner. Commercial cleaners work quickly and efficiently so that you can enjoy a clean workspace all the time!

2. Increases the Reputation of Your Company

A clean space helps shape client perceptions of your company as professional and well-maintained. Hiring a top-notch commercial cleaning in Perth to regularly clean and disinfect your office not only ensures a pristine environment but also sends a powerful message to clients that you prioritize cleanliness and hygiene in your business operations

Cleaning your business yourself or asking employees to take on this task takes away valuable time that could be spent on more productive activities. Commercial cleaners can get the job done quickly and efficiently. They also ensure the quality of their work by utilizing high-quality equipment and cleaning solutions.

3. Reduces Stress

A clean workspace can make a positive first impression on clients and customers. It also conveys a professional image and shows that you care about your business.

An office that is cluttered and messy can cause stress for employees. This can lead to reduced productivity and lower morale. A commercial cleaning service can take this stress off your plate, so you and your employees can focus on your work.

A clean office can help reduce the spread of germs and viruses. This can reduce the number of sick days that your employees have to take and can boost productivity.

4. Increases Productivity

Professional cleaning services make sure all areas of your office are clean and organized. This can help increase productivity because employees will be able to focus on their work without being distracted by a dirty environment.

A clean workspace can also reduce employee sick days, which can save your company money in the long run. Hiring commercial cleaning services is often a more cost-effective option than employing in-house cleaners.

Keeping your office clean shows employees that you care about them and their job satisfaction, which can lead to higher morale and productivity. It can also give your business a more professional appearance and attract potential customers.

5. Reduces the Risk of Illness

When your employees are focusing on cleaning duties instead of working, they are not able to get as much done. This can lead to a loss in productivity for the entire office, especially if one employee gets sick.

With a professional cleaner using Calgary janitorial supplies, you can reduce the spread of germs and create a healthy workplace. This can save you money on lost wages, employee sick days, and potential insurance claims. A clean office also means healthier, more productive employees. This is something every company can benefit from!

6. Improves Indoor Air Quality

Often, cleaning tasks are overlooked or pushed to the bottom of the to-do list when a business is busy. However, a commercial cleaning service ensures that these tasks are taken care of and are done with high-quality cleaning products.

Dirty office spaces are not just unsightly; they can also be unhealthy. Dust, germs, and bacteria can accumulate in the air. These contaminants can cause a range of health problems from allergies to asthma.

A professional commercial cleaning company reduces indoor pollution, making the workspace a safer and more pleasant place to work.

7. Saves You Money

A clean business makes a great first impression to clients and customers. It also shows that you are professional and organized.

Having a professional cleaning service saves you money in the long run. Employees who have to clean the office are not productive, and their time could be better spent working on important projects for the company.

Commercial cleaning services bring their own supplies and equipment, so you won’t have to spend money on purchasing and storing them. This can be a big savings for businesses on tight budgets.

8. Reduces Employee Sick Days

Fewer employee sick days can mean fewer lost productivity hours for your company. Having a clean workspace and regularly disinfecting high-touch areas reduces the spread of germs that can cause illness and lead to employees calling in sick.

When employees have to juggle cleaning tasks with their regular job duties, the cleaning can be rushed or may even get neglected. Commercial cleaners can be trusted to perform consistent cleaning and sanitization, helping your employees stay focused on work rather than on household chores. This can help prevent accidents that result in costly worker’s compensation claims.

9. Saves You Money in the Long Run

While hiring a commercial cleaning service may seem like an expense, it’s actually more cost-effective than trying to clean your workplace yourself or having employees do the job. Commercial cleaning services ensure that your work space is free from clutter, which can cause tripping and fire hazards.

They also take care of trash disposal and clean kitchen and washroom areas. This saves you time and money that could be spent on more productive business activities. A clean workspace gives a positive first impression to your clients and customers, which increases the value of your company.

10. Saves You Time

One of the biggest benefits of hiring a commercial cleaning service is that it can save you time. You and your employees have enough on their plates without having to worry about cleaning duties. Trying to fit in cleaning tasks on top of traditional job duties can lead to lower-quality work and less time spent on essential business functions.

In addition, hiring a commercial cleaning company can save you time and money on supplies and equipment. This is because a professional cleaning company will bring their own supplies to the office and clean your space on a regular schedule.