Understanding Ceramic Glaze Components Part 4: Colorants

<p>World Youth Skills Day,established by the United Nations in 2014,is observed on July 15 each year to raise awareness of the critical role technical and vocational skills play in empowering young people. Despite the declining emphasis on arts education in many school systems,hands-on fields like ceramics continue to offer powerful opportunities for broader skill development. The multifaceted craft of ceramics nurtures both creative and practical skills,preparing young people not only for artistic pursuits but also for a wide range of careers and challenges. For those drawn to creating with their hands,learning ceramics can build confidence,resilience,and adaptability—qualities crucial for navigating the complexities of today’s world.</p>



<p>If you’ve been looking for a new activity to enroll your child in that’s not only engaging,but also offers long term benefits,clay is well worth a consideration. Let’s have a closer look at five specific benefits that developing ceramic skills can provide!&nbsp;</p>



<h2 class="wp-block-heading">Problem-Solving and Adaptability</h2>



<p>Ceramics teaches young people to plan,experiment,and make adjustments as they go. Whether troubleshooting issues with clay consistency,figuring out how to prevent pieces from cracking as they dry,or exploring ways to build more complex forms,ceramics teaches flexibility and problem-solving. And while it may be difficult when a piece doesn’t survive in the kiln (even for us adults!),ceramics teaches kids that there is nothing wrong with starting over from the beginning,that ‘failure’ is not something to be discouraged by,but rather something to be embraced on the path of progress. These hands-on challenges help students develop patience and adaptability,skills that are valuable in any career path.&nbsp;</p>



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<h2 class="wp-block-heading">Mindfulness and Stress Relief</h2>



<figure class="wp-block-image alignleft is-resized"><img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXcTSNNLxUJjPDTBZ64ZLi_czui5QGc_kUAubEADFML0ji8Gn2o3FWPd3DUDOOEGjDMPgI6W9ZcfHyA1xmtVaXTDsc6Xb_BGY-OdEzesIOLiguIYjGDGiFHkzdIiFSae73sYhm8-JC8JzU4ElhfPN9KO69D7?key=vcHOPWur4Mk251dwxnQ1YFhB" alt="" style="width:373px;height:auto"/></figure>



<p>The tactile nature of working with clay provides a calming,meditative experience for young people. Working with clay encourages kids to focus on the sensations and movements of their hands,helping them to stay present and engage fully with the process. <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC8936381/">Research has found</a> that engaging in mindful,hands-on activities like ceramics can lead to increased emotional resilience,improved concentration,and even better self-regulation skills,all of which are important for overall well-being and success in school and life. This grounding,creative process helps children cultivate a mindset that values patience and progress over perfection,building a foundation of mental resilience that they can carry into other areas of life.</p>



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<h2 class="wp-block-heading">Creativity and Imagination</h2>



<p>Ceramics nurtures creativity and invites young people to explore their imaginations in three-dimensional form. From envisioning the shape of a vessel to creating unique textures or experimenting with colors,clay work encourages students to think creatively and bring their ideas to life. Imagination in ceramics isn’t just about making something beautiful—it involves thinking beyond what’s conventional,taking risks with new designs,and exploring “what if” scenarios. <a href="https://online.maryville.edu/online-bachelors-degrees/psychology/resources/creativity-for-kids-benefits-tips-for-nurturing-an-innovative-mind/">Studies suggest that imaginative play and creative expression can improve problem-solving skills and boost self-confidence in young people</a>. These exercises in creativity help children build flexibility in thinking,laying the groundwork for innovation in future challenges,whether in artistic pursuits or other fields.</p>



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<h2 class="wp-block-heading">Enhanced Fine Motor Skills and Coordination</h2>



<p>Working with clay requires young people to engage their hands and fingers in precise,controlled movements,which helps build fine motor skills. Whether they are rolling coils,pinching small details,or carefully smoothing surfaces,each movement hones their hand-eye coordination and finger dexterity. These fine motor skills are essential not only for artistic pursuits but also for daily activities and tasks in many fields,from science and technology to culinary arts. The act of shaping,pressing,and manipulating clay requires both concentration and physical control,reinforcing the connection between the mind and body. For younger children,these activities are particularly beneficial,as developing strong motor skills supports writing,drawing,and other skill-building activities that are crucial during developmental years.</p>



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<h2 class="wp-block-heading">Teamwork and Social Skills</h2>



<p>Many ceramics classes or workshops encourage group projects and collaborative work,which helps young people build teamwork and communication skills. Working alongside others,whether on shared projects or simply in a communal studio space,allows students to exchange ideas,give and receive constructive feedback,and support each other in problem-solving. This collaborative environment nurtures social skills,empathy,and a sense of community—qualities that can enhance their interpersonal skills both in and out of the studio.</p>



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<h2 class="wp-block-heading">Building Strong Foundations</h2>



<p>In a world where practical skills and creative thinking are increasingly valuable,working with clay offers young people a powerful blend of artistic and personal development. From building motor skills to cultivating mindfulness,ceramics provide a foundation that supports both individual growth and readiness for the challenges ahead. By embracing opportunities to create with their hands,young people gain not only a deeper appreciation for the arts but also essential skills that can serve them for a lifetime. On World Youth Skills Day,let’s celebrate and support the role that ceramics and other creative practices play in shaping the resilient,imaginative,and skillful generation of tomorrow.</p>



<p>If you’d like to introduce clay to your child and are looking for some fun project ideas to get them started,be sure to check out our blogs <a href="https://staging.ceramic.school/ceramics-for-kids-easy-and-fun-projects-for-young-makers/">Ceramics for Kids: Easy and Fun Projects for Young Makers</a> and <a href="https://staging.ceramic.school/5-more-creative-clay-projects-for-kids/">5 More Creative Clay Projects for Kids</a>. Or,if you’re looking for something more in-depth,why not join our <a href="https://staging.ceramic.school/airdryclayclub/">Air-Dry Clay Club</a>? We’ve developed a great selection of kiln-free clay projects supported by easy-to-follow PDF downloads!</p>

The Benefits of Teaching Ceramics to Young People

<p>The holiday season is the perfect time to channel your ceramic creativity into festive projects to fill hearts with warmth and joy.</p>



<p>Whether you're looking to create unique gifts,holiday decorations,or simply want to explore new techniques in a seasonal context,these ceramic Christmas projects will inspire you to add a handcrafted touch to the celebrations. From timeless ornaments to table pieces with a festive twist,here are five projects that will make your holiday season even more special!</p>



<figure class="wp-block-image is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/12/AD_4nXc_ojTsqOLYhhNFiURStui38gHFF0THSPkYT8_0z7TgE0oyIvd0mALIrq1k7QKFM-55YDenSD_-ivXokjvpbh0uC4FtGpOeigKFzHDadhFTYO5hxglzaP1riTqz7uIJQh7NwDcmqRlHjqM1JVoyp8uWXFWS.png" alt="" class="wp-image-155298" style="width:364px;height:auto"/></figure>



<h2 class="wp-block-heading">1. Wheel-Thrown Christmas Baubles</h2>



<p><a href="https://www.youtube.com/watch?v=vot8lBbydB4" target="_blank" rel="noreferrer noopener">Watch video on YouTube</a> </p>



<p>Practice your closed-form throwing techniques with this great Christmas project by our friend <a href="https://karaleighfordceramics.com/home" target="_blank" rel="noreferrer noopener">Kara Leigh Ford</a>. These elegant baubles offer plenty of opportunity to play with form and surface,and offer endless glazing and surface decoration possibilities as well! </p>



<figure class="wp-block-image is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/12/AD_4nXcWmtuWYVOFx5ud_O-9Mf7HOL6m_jC3xYVqlo7QohRsEdwoaxsMGK3cr5GYNi2nzBUUYEQUuAyXbMpikk3qsYhEExEsCpBrGEbpOY9T8TXhxyNRVxvvWoifP7u2ndkWRK5iGFyHQX-IESmO-vssmPHqhJwA.png" alt="" class="wp-image-155297" style="width:357px;height:auto"/></figure>



<h2 class="wp-block-heading">2. Pinch Pot Jingle Bells</h2>



<p><a href="https://www.youtube.com/watch?v=YIZJab1KILM">Watch video on YouTube</a>&nbsp;</p>



<p>For a ceramic take on the classic brass jingle bell,check out this great tutorial by Mount Penn Art. If pinching isn’t your thing,this project can be easily modified using press molded slabs. The finished bells make a perfect addition to your christmas tree or holiday wreath!</p>



<figure class="wp-block-image is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/12/AD_4nXelHBI3sjEMhVNq4y1PxEzdIUeLFDOwWNJY5cAqpYlckTdPxDdz3As8kJiXPMj97PEON53AC07lHzUUIFgZwrGZI5PouiC9QyBG4V7CIWE1rPDBqJQLBW69Dtu0GIO_rnT3-Mh9huM0tGIk-0cTulLqZuQ.png" alt="" class="wp-image-155299" style="width:372px;height:auto"/></figure>



<h2 class="wp-block-heading">3. Wheel-Thrown Christmas Trees</h2>



<p><a href="https://www.youtube.com/watch?v=I18oFU5sFHA" target="_blank" rel="noreferrer noopener">Watch video on YouTube</a> </p>



<p>This video by Ondo Studio demonstrates a fun and simple way to create an elegant Christmas tree sculpture on your wheel. By marking out the layers of the tree while throwing,you give yourself an easy guide for trimming,where you’ll really bring your form to life. Once off the wheel,you can add more detail with your carving tools,or keep it simple and geometric — the choice is yours!</p>



<h2 class="wp-block-heading"><img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXdh0Zl4hOgkkwFj-pbh5KrcS3DLwn5xUIHEqUTAsZnAn8FgZ_xWHb-yifOOmgd4jiKIDg0HPIit3_1ogRXdVqIt7ZZRHyf3ZCXrSBXr0xsUBmH4e7HWYV4Vy8N4AB1NY33RopwtA6813DyPPAp17PPRTuRc?key=41TtojacalAjJEpJNQ8xgw" width="328" height="168.45981624247543"></h2>



<h2 class="wp-block-heading">4. Christmas Wreath Candle Holder</h2>



<p><a href="https://www.youtube.com/watch?v=hqF6jOR4mXU&amp;list=PLJYMHnsfapqIAgFZ5qMVDWL0WuZqykK9a&amp;index=13" target="_blank" rel="noreferrer noopener">YouTube Video Part 1</a></p>



<p><a href="https://www.youtube.com/watch?v=Xph-M1IUDxo&amp;list=PLJYMHnsfapqIAgFZ5qMVDWL0WuZqykK9a&amp;index=14">YouTube Video Part 2</a></p>



<p>This fun and unique project is by <a href="https://staging.ceramic.school/courses/calder-van-andel-bubble-glaze-technique/">our friend Calder van Andel</a>,and it offers plenty of opportunities for decoration and customization. In part one,Calder walked you through the throwing process for creating the closed donut form that is the basis for the wreath,while in part two he’ll show you some decorating and finishing ideas. If you’re looking for a unique centerpiece for your Christmas table,this is the project for you!</p>



<figure class="wp-block-image is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/12/AD_4nXfM61cU1cdTHj7GsIx7ihouN_n-UuH1vWXGkoz5jfo3w4UuHpXFrfohmEec7M9l3NH1yL3TjTAgTIlT7SBcfYP_QRjwpsB8s195bKLc8rsr9QoSEa83QVTNvi3ndLuUJYCI2zt_XVUkjH5HiDw26Yf6prwt.jpg" alt="" class="wp-image-155296" style="width:282px;height:auto"/></figure>



<h2 class="wp-block-heading">5. Hand-Built Tree Ornaments</h2>



<p><a href="https://ceramicartsnetwork.org/pottery-making-illustrated/pottery-making-illustrated-article/handmade-holiday-ornaments#" target="_blank" rel="noreferrer noopener">Read the article on Ceramic Arts Network</a></p>



<p>This step-by-step tutorial by Pottery Making Illustrated is a fun and easy project suitable for the whole family. Using simple texturing and slab building techniques,you can create beautiful pillow-like ornaments that are sure to add festive elegance to your Christmas tree!</p>



<p>As the holiday season approaches,these ceramic Christmas projects offer the perfect opportunity to embrace the joy of creating something special. Whether you're crafting thoughtful gifts or adding festive flair to your home,each project is a chance to explore new ideas and techniques while celebrating the season's spirit of giving. So,gather your tools,fire up the kiln,and let your creativity shine this Christmas. Happy crafting and happy holidays!</p>

5 Ceramic Christmas Projects for You to Try

Understanding Glaze Composition Part 2: Flux

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<p class="has-background" style="background-color:#f4f9ff"><a href="https://www.youtube.com/watch?v=-YCGK33c0xs" target="_blank" rel="noreferrer noopener nofollow">This amazing video shown above</a> which is full of helpful visual insights was posted by <a href="https://www.youtube.com/@floriangadsby" target="_blank" rel="noreferrer noopener nofollow">Florian Gadsby</a>.​</p>



<p>Hey,so you wanna center clay on the wheel? Awesome. Let’s get into it.</p>



<p>If you’ve ever sat down at the wheel,slapped a ball of clay on there,and watched it wobble around like it’s got a mind of its own,you’re not alone. Centering is one of those make-or-break skills in pottery.</p>



<p>If your clay isn’t centered,everything else... opening,pulling,shaping... becomes ten times harder. </p>



<p>But don’t stress,I’m gonna walk you through it step by step.</p>



<h3 class="wp-block-heading">Step 1: Prepping Your Clay</h3>



<p>Before you even touch the wheel,you gotta wedge your clay. Think of wedging like kneading bread dough - it gets rid of air bubbles and makes the clay smooth and uniform. If you skip this step,you might end up with little pockets of air that can mess up your piece later.</p>



<p>Once your clay is wedged,shape it into a ball. Doesn’t have to be perfect,just roundish. A good shape helps it stick to the wheel better and makes centering easier.</p>



<p class="has-background" style="background-color:#f4f9ff"><strong>Wedging:</strong> Begin by kneading the clay to eliminate air bubbles and achieve a uniform consistency. This process,known as wedging,aligns the clay particles,making it more workable.​<br><strong>Shaping:</strong> After wedging,mold the clay into a smooth,spherical shape. This initial form facilitates easier centering on the wheel.</p>



<h3 class="wp-block-heading">Step 2: Getting Set Up</h3>



<p>Alright,now let’s talk about you. How you sit at the wheel matters more than you think. Get close enough so your arms can rest on your thighs or the splash pan - this helps stabilize your movements. Keep your back straight but not stiff,and plant your feet firmly on the ground. You want to feel balanced and in control.</p>



<p class="has-background" style="background-color:#f4f9ff"><strong>Seating and Posture:</strong> Sit comfortably at the wheel,ensuring your legs are parallel to the ground. Maintain a straight back and position yourself close enough to the wheel to allow your arms to rest on your thighs or the splash pan for stability.​</p>



<h3 class="wp-block-heading">Step 3: Sticking the Clay Down</h3>



<p>Take your ball of clay and give it a solid slam onto the middle of the wheel head. Don’t be shy! You want it to stick so it doesn’t fly off when you start spinning. Once it’s down,press it firmly with both hands to make sure it’s really secured.</p>



<p class="has-background" style="background-color:#f4f9ff"><strong>Placing the Clay:</strong> With the wheel stationary,firmly press the clay ball onto the center of the wheel head. Apply downward pressure to ensure it adheres securely,preventing any movement during the centering process.​</p>



<h3 class="wp-block-heading">Step 4: Centering the Clay</h3>



<p>Now the fun begins. Turn the wheel on - medium to high speed is best. Add a little water to keep things moving smoothly,but not too much or the clay will get too soaked and start to disintegrate.</p>



<p>Your left hand should be anchored - think of it like a wall keeping the clay in place. And your right hand? That’s gonna push down from the top. The trick is applying steady,even pressure.</p>



<p>You’ll want to “cone” the clay up by squeezing it between both hands,then push it back down. This helps align the clay particles and gets everything working together. Repeat this a couple of times. If your hands are bouncing or the clay is pushing back at you,that’s a sign it’s not centered yet. Keep going.</p>



<p class="has-background" style="background-color:#f4f9ff"><strong>Wheel Speed:</strong> Start the wheel at a moderate to high speed. The appropriate speed provides the necessary centrifugal force to assist in the centering process.​<br><br><strong>Hand Placement and Pressure:</strong><br><strong>Anchor Your Arm:</strong> Brace your left elbow against your hip or thigh,creating a stable anchor point. This stability is crucial for controlling the clay's movement.<br><strong>Left Hand Technique:</strong> Place your left hand on the side of the clay,with the thumb pointing upward and fingers pointing downward. This hand applies inward pressure to the clay.​<br><strong>Right Hand Technique:</strong> Position your right hand on top of the clay,with fingers pointing towards the center. This hand applies downward pressure.​<br><strong>Applying Pressure:</strong> Simultaneously press inward with your left hand and downward with your right hand. This combined pressure directs the clay towards the center,reducing any wobbling.​<br><strong>Coning:</strong> Gently squeeze the clay upward into a cone shape by applying inward pressure with both hands. Then,press it back down into a dome shape. Repeating this "coning up and down" process several times helps align the clay particles and ensures uniformity.</p>



<h3 class="wp-block-heading">Step 5: Checking Your Work</h3>



<p>How do you know when it’s centered? Here’s the test: lightly rest your hands on the clay. If it feels smooth,with no bumps or wobbles,congrats - you nailed it! If not,keep applying pressure and adjusting until it stops fighting you.</p>



<h3 class="wp-block-heading">Troubleshooting Common Problems</h3>



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<li><strong>Still wobbly?</strong> You might not be applying enough pressure or your hands aren’t steady. Try locking your elbows to your body for more control.</li>



<li><strong>Feeling frustrated?</strong> That’s normal. Nobody gets this perfect on their first try. Or their second. Or their tenth. It takes practice,so don’t give up!</li>
</ul>



<p>Centering is one of those skills that takes time. There’s no magic shortcut - it’s all about muscle memory and practice. But once you get it down,everything else in pottery starts to feel a whole lot easier. So keep at it,be patient,and don’t be afraid to get your hands dirty.</p>



<p>Happy throwing!</p>

How to Center Clay - A Beginner's Guide

<p>Whether you’re working with commercial glazes or looking to start mixing or developing your own,understanding the basic structure of glazes can be a big help in getting successful results. It’s easy to get overwhelmed by the sheer number of possible ingredients and complicated recipes,but you don’t need a chemistry degree to improve your understanding.</p>



<p>In this new series,we’re going to cover the three essential components that all glazes have: <strong>fluxes</strong>,<strong>glass-formers</strong>,and <strong>stabilizers</strong>. We’ll look at what they do,how they work together,and which ingredients can provide them. And later in the series,we’ll look at the most common additions to glazes: <strong>opacifiers </strong>and <strong>colorants</strong>.&nbsp;</p>



<p>By breaking your glazes down into these basic categories,you’ll have a better understanding of how your ingredients are contributing to your glaze,and which ones to adjust to get your desired results. It will also help you make substitutions if you suddenly lose access to a particular material.</p>



<p>We’re going to start off our glaze journey today with the foundational element of most any glaze: <strong>the glass-former</strong>.<br></p>



<figure class="wp-block-image size-full is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/Galloway-Sphere-Matthew-Blakely.jpg" alt="Galloway Sphere by Matthew Blakely featuring a glossy glaze" class="wp-image-152410" style="width:313px;height:auto"/><figcaption class="wp-element-caption"><sup><a href="https://staging.ceramic.school/courses/matthew-blakely-making-glazes-from-rocks-clays-and-ash/">Galloway Sphere by Matthew Blakely</a>,</sup><br><sup>featuring a high-gloss glaze</sup></figcaption></figure>



<h2 class="wp-block-heading">Why do Glazes Need a Glass-Former?</h2>



<p>Now,you’ve probably already noticed that most glazes,especially glossy ones,have a glass-like feel. That’s no coincidence,since glaze,at its core,is a skin of glass. Glazes were originally developed to make pots more water-tight and strong,and glass is the perfect material to do this. It’s hard and dense,with little porosity.&nbsp;</p>



<p>Since we are applying the glaze to a three-dimensional object,we need to source our glass-former in a powdered form which can be suspended in water. Later,we’ll use the heat of the kiln to melt it and fuse it to our work.</p>



<h2 class="wp-block-heading">Where Do We Source Glass-Formers?</h2>



<p>Glass is formed essentially by one ingredient: silica,or more accurately silicon dioxide (SiO2). You’ve likely already noticed it is a common ingredient in glaze recipes. It’s a foundational component of glass,and is found in common materials such as sand,limestone,mica,and many others. For the purposes of glazing,we can source silica from a number of materials. Let’s have a look at a few of them below.</p>



<h3 class="wp-block-heading">Quartz/Flint/Silica</h3>



<figure class="wp-block-image size-large is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/quartzcrystal-910x1000.jpg" alt="A quartz crystal" class="wp-image-152411" style="width:315px;height:auto"/><figcaption class="wp-element-caption"><sup>A quartz crystal,<a href="https://australian.museum/learn/minerals/gemstones/quartz/" target="_blank" rel="noreferrer noopener">Australian Museum</a></sup></figcaption></figure>



<p>Quartz is a near-pure form of silica that is naturally forming,and you’ll likely see it as the main source of silica in many glazes.  It is formed in igneous or metamorphic rocks <a href="https://digitalfire.com/material/1245" target="_blank" rel="noreferrer noopener">as silica cools over long periods of time</a>,a process which forms large angular crystals. Quartz has a very high melting point and a high rate of thermal expansion. </p>



<p>You’ll often see the terms quartz,flint,and silica used interchangeably in recipes and at your pottery supply store,and this can create some confusion. By definition,flint is different from quartz,being a finer particle found in sedimentary rocks. True flint is very high in silica (at about 94%),but it does contain more inclusions of other minerals than quartz. It has been used in glazes,but is actually not commonly used in glazes today. The ‘flint’ you’re seeing in your glaze recipe today is actually ground quartz,and,<a href="https://digitalfire.com/material/316" target="_blank" rel="noreferrer noopener">since it is no longer in its crystalline form,it is most accurately called silica</a>.</p>



<p>You may come across different “meshes” of silica,such as Silica 200 or Silica 325. This refers to the particle size of the material. The larger the number,the finer the particle. Generally speaking,finer grades melt slightly earlier,but in most cases it won’t make a significant difference in your glaze.</p>



<p>Because it melts at a high temperature,you will often see low amounts of silica in earthenware glazes,but as much as 30% in glazes for high firing stonewares.</p>



<h3 class="wp-block-heading">Wollastonite</h3>



<figure class="wp-block-image size-full"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/wollastonite.jpeg" alt="crystalline wollastonite" class="wp-image-152412"/><figcaption class="wp-element-caption"><a href="https://www.minerals.net/mineral/wollastonite.aspx" target="_blank" rel="noreferrer noopener"><sup>Wollastonite in crystalline form</sup></a></figcaption></figure>



<p>This is calcium silicate,so you can see the presence of silica in the name itself. It consists of 51.72% silica and is a naturally occurring white mineral. This material is primarily used for its calcium content,which is a powerful flux (we’ll cover fluxes in Part 2),but it's important to be aware of the amount of silica it’s contributing to your glaze.</p>



<h3 class="wp-block-heading">Kaolin</h3>



<figure class="wp-block-image size-full"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/Kaolin-2-4.jpg" alt="kaolin clay in various forms" class="wp-image-152413"/><figcaption class="wp-element-caption"><a href="https://www.hmicronpowder.com/industry/mineral/kaolin/" target="_blank" rel="noreferrer noopener"><sup>Kaolin in various forms</sup></a></figcaption></figure>



<p>Probably better known for its role in porcelain clay,kaolin is also a common glaze ingredient. It contains both silica (it’s made of up to 47.29% of it),and alumina oxide,which is a stabilizer (we’ll cover this in Part 3). While contributing silica itself,kaolin is most commonly used to prevent your main source of silica from settling out in your mixture.</p>



<h3 class="wp-block-heading">Feldspars</h3>



<figure class="wp-block-image is-resized"><img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXcZasgXfRG4oQw3_5DOqSpD5ZALGspmnb8FZDtrTBM4nzPm8Fvzp1_cA1G2DqQxtdnHQJyjzgw4FUB6xGL2R6iy10xVa0OugX9Fqcs3dVz3ybXcJV0L_cTDOaFBKm2jjuRNd8gmKTRknTT-O10IUaeSxwwt?key=IdgGFbX7HXGBUmQdnOmfhw" alt="raw feldspar" style="width:422px;height:auto"/><figcaption class="wp-element-caption"><a href="https://www.finoreminerals.com/potash-feldspar.html?i=1"><sup>Potash Feldspar in raw for</sup></a><a href="https://www.finoreminerals.com/potash-feldspar.html?i=1" target="_blank" rel="noreferrer noopener"><sup>m</sup></a></figcaption></figure>



<p>Feldspars are practically full glazes in and of themselves,containing silica,refractories,and fluxes. The feldspar powders that we use in ceramics are made from <a href="https://digitalfire.com/material/310" target="_blank" rel="noreferrer noopener">crushed crystalline rock containing a mixture of aluminum silicates of sodium and potassium</a>,and smaller amounts of other minerals. Feldspars can be composed of up to 65% silica,though they are more commonly used for their fluxing properties. <em>Fun fact: feldspar is the most common mineral type on Earth,with quartz being second!</em></p>



<h3 class="wp-block-heading">Bentonite</h3>



<figure class="wp-block-image size-full"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/bentonite_325_powder.jpg" alt="powdered bentonite" class="wp-image-152414"/><figcaption class="wp-element-caption"><a href="https://www.theceramicshop.com/product/325/bentonite-325-mesh/" target="_blank" rel="noreferrer noopener"><sup>Bentonite in powdered form</sup></a></figcaption></figure>



<p>Also containing 59.00% silica,bentonite is usually only added to glazes in small amounts (1-2%),so it’s not going to add too much silica to your glaze. Its main use is to prevent your glaze from settling out. It is a clay-based material with a very high degree of plasticity.</p>



<h3 class="wp-block-heading">Ball Clays</h3>



<figure class="wp-block-image is-resized"><img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXe5zO5aiPEESNSqbCKAQgix6f-kZxLlLkFgJv3YFTpiIHQyh3cXyqY4giH3cdV-lYm1U_Zeavi9CiI7C6j3ltYMdKzSIELgnbn6j4NaweWEAajqe0CHR6pW6V0ga0qwvROpFnrUo2orBGg80NtpqKT4vXk?key=IdgGFbX7HXGBUmQdnOmfhw" alt="ball clay mine" style="width:383px;height:auto"/><figcaption class="wp-element-caption"><sup><a href="https://arteologic.com/en/ceramics/ceramic-materials/ball-clay/" target="_blank" rel="noreferrer noopener">Ball clay at a mining site</a> </sup></figcaption></figure>



<p>Ball clays are fine,plastic clays that are formed by the deposition of clay minerals and volcanic ash. <a href="https://glazy.org/recipes/15058" target="_blank" rel="noreferrer noopener">They contains kaolinite,quartz,mica,titanium,iron,and small amounts of feldspars,bentonite,and illite</a>. Ball clay also tends to contain varying amounts of organic matter. They can contain up to 59.00% silica,but are typically employed in glazes to <a href="https://digitalfire.com/material/80" target="_blank" rel="noreferrer noopener">help suspend and harden them,and control their shrinkage during drying</a>.</p>



<h3 class="wp-block-heading">Frits</h3>



<figure class="wp-block-image is-resized"><img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXf3e5JWbyMgXu1x_iC-R3pULEggmaej3Yil1JrpJnLR76Phk7HxqDmScKok4I0rd32juPW111bLkzMhl8UwCwhglKTsvVpOrWkHl4-OxyqrAJSHdlZ-rRY-27Ad8JG8ls355fwfbT_lxqseR8tDNxz0FP_s?key=IdgGFbX7HXGBUmQdnOmfhw" alt="frit 3269" style="width:320px;height:auto"/><figcaption class="wp-element-caption"><a href="https://glazy.org/materials/15175" target="_blank" rel="noreferrer noopener"><sup>Ferro Frit 3269</sup></a></figcaption></figure>



<p>Frit is another ingredient that is primarily used for its fluxing properties. Frits are manufactured materials that primarily consist of ground glass. We’ll go into a lot more detail about frits in our next article,but be sure to keep the silica content of them in mind when you are adding them to your glaze. As they are manufactured,there are numerous different ones available,each with a differing percentage of silica.</p>



<p>We hope that today's article has helped demystify one of the core components of glaze composition: <strong>the glass-former</strong>. From its vital role in creating smooth glassy surfaces,to understanding what ingredients provide it,you now have a better understanding of this fascinating material. Be sure to join us in Part 2 of this series,where we’ll delve into the importance of fluxes.</p>



<p>If you would like to learn more about glazes and their chemistry,be sure to check out our selection of glaze workshops! Why not sign up for <a href="https://staging.ceramic.school/courses/greg-daly-developing-glaze-surfaces/">Greg Daly’s “Developing Glaze Surfaces</a>” or <a href="https://staging.ceramic.school/courses/matthew-blakely-making-glazes-from-rocks-clays-and-ash/">Matthew Blakely’s “Making Glazes from Rocks,Clays,and Ash.</a>”? No matter what your level of glazing experience,we have a workshop perfect for you!</p>

Understanding Glaze Composition Part 1: Glass-Formers

<p>Welcome to our third and final installment of our “Understanding Clay Bodies” series!</p>



<p>Having previously had a look at <strong><a href="https://staging.ceramic.school/understanding-clay-bodies-part-1-earthenware/">earthenware</a> </strong>and <strong><a href="https://staging.ceramic.school/understanding-clay-bodies-part-2-stoneware/">stoneware</a></strong>,today we’re exploring the development and use of the highly-prized and frequently romanticized clay that is <strong>porcelain</strong>. With a name originating from the Spanish ‘<em>porcellana’,</em>meaning cowrie shell,this unique clay was once valued as ‘white gold’,and continues to be considered the finest of the main clay types used today.</p>



<figure class="wp-block-image is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/image-12.jpeg" alt="" class="wp-image-151430" style="width:328px;height:auto"/><figcaption class="wp-element-caption"><a href="http://www.chinatoday.com.cn/ctenglish/2018/cs/201810/t20181011_800143922.html" target="_blank" rel="noreferrer noopener"><sup>White Xing Pot in the Shape of a Leather Bag<br></sup></a><sup>(Palace Museum in Beijing)</sup></figcaption></figure>



<h2 class="wp-block-heading">A Brief History of Porcelain</h2>



<p>Porcelain was first developed in China somewhere around <a href="https://en.wikipedia.org/wiki/Porcelain" target="_blank" rel="noreferrer noopener">2,000 to 1,200 years ago</a>,which is why today wares of this material are often referred to as ‘China’. Some of the earliest evidence of porcelain pieces <a href="https://www.kaolin.com.au/history-porcelain/" target="_blank" rel="noreferrer noopener">have been traced to the Eastern Han Dynasty</a>,when China’s famous jade green Celadon glaze was very popular. Its use soon spread throughout Asia and by the time of the Song dynasty,artistry and production reached new heights. The manufacture of porcelain became highly organized at this time,and continued to evolve into the Ming dynasty and beyond.</p>



<p>In the 14th century,the first porcelain made its way to Europe thanks to Marco Polo. Later,after the establishment of Dutch and Portuguese trade routes to the Far East in the 16th century,a <a href="https://www.newyorker.com/books/page-turner/the-european-obsession-with-porcelain" target="_blank" rel="noreferrer noopener">market of Chinese porcelain ware created purely for export to Europe emerged</a>. </p>



<p>With the popularity and value of porcelain wares,the race was on in Europe to crack the secret of porcelain and be the first to produce it domestically. <a href="https://en.wikipedia.org/wiki/Johann_Friedrich_B%C3%B6ttger" target="_blank" rel="noreferrer noopener">German alchemist Johann Friedrich Böttger</a> is most commonly credited as being the first European to successfully produce porcelain in 1708 while working for the Meissen factory near Dresden. This has been disputed,however,with some claiming the honor goes to his supervisor,German <a href="https://en.wikipedia.org/wiki/Ehrenfried_Walther_von_Tschirnhaus" target="_blank" rel="noreferrer noopener">Ehrenfried Walther von Tschirnhaus</a>,and others still saying the first successes were in the UK. Whichever the case,the formula developed at Meissen catapulted the large scale production of porcelain in the continent,with the factory maintaining a world-renowned reputation to this day.</p>



<figure class="wp-block-image is-resized"><img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXcXDdUSl2QqgYNxW1_z8Lr9Wk9gmOsb2d9spwcsdkliapZt3WnC6676N_0PK-lhHkqXgpk2bGzTogXGLItf23ZtcsBw9VdwW2YnFv48R0Y5qyJEY8ivnMseS-uInOLvX7iOhEZuf4CwoT6XBuUz8IFRksg?key=lr0xqDitl52IOYLwgCKbOA" alt="" style="width:266px;height:auto"/><figcaption class="wp-element-caption"><a href="https://staging.ceramic.school/courses/guy-van-leemput-porcelain-bowl/" target="_blank" rel="noreferrer noopener"><sup>Guy Van Leemput</sup></a></figcaption></figure>



<h2 class="wp-block-heading">Porcelain Properties</h2>



<p>What was it exactly that made porcelain so sought after and so difficult to produce? We mentioned earlier that the name was derived from the Spanish word for cowrie shell,and this is because the surface of the fired clay was as smooth,strong,and beautiful as those shells.&nbsp;</p>



<p>Porcelain is generally composed of three components: <strong>kaolin</strong>,<strong>feldspar </strong>and <strong>quartz</strong>. Kaolin is the key ingredient here,a unique white type of naturally occurring clay which<a href="https://en.wikipedia.org/wiki/Kaolinite" target="_blank" rel="noreferrer noopener"> takes its name from Gaoling</a>,the village in Jingdezhen,China where it was first used. It’s composed of alumina silicate,and provides the characteristic white or blue-white color that has become synonymous with porcelain.</p>



<p>In addition to its flawless color,porcelain is renowned for vitrifying at high firing temperatures,which makes it completely non-porous,water tight,and strong. This density also results in a higher shrinkage rate than earthenware and stoneware,with some shrinking as much as 16%.</p>



<p>Porcelain is also famous for its ability to be worked incredibly thinly,to the point of transparency. This is due to its fine particle size,which also allows for finely carved surfaces. This does have its drawbacks however,as it makes it a difficult clay to work with,with a strong memory and a high sensitivity to water.&nbsp;</p>



<h2 class="wp-block-heading">Types of Porcelain</h2>



<p>Porcelain clays can be divided into three main types: <strong>hard-paste porcelain</strong>,<strong>soft-paste porcelain</strong>,and <strong>bone china</strong>. Let's have a look at the characteristics of each type.</p>



<figure class="wp-block-image size-large is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/HardpasteTeapot-1000x990.jpeg" alt="" class="wp-image-151426" style="width:330px;height:auto"/><figcaption class="wp-element-caption"><sup>Chinese with Dutch decoration,for European market,<br>18th century,decorated ca. 1730–40,<a href="https://www.metmuseum.org/art/collection/search/208282" target="_blank" rel="noreferrer noopener">The MET</a></sup></figcaption></figure>



<h3 class="wp-block-heading">Hard-Paste Porcelain</h3>



<p>Sometimes called ‘true porcelain,’ this variety was originally made <a href="https://en.wikipedia.org/wiki/Hard-paste_porcelain" target="_blank" rel="noreferrer noopener">from a compound of the feldspathic rock petuntse and kaolin</a>,and is fired to very high temperatures,typically around 2550°F (1400°C). The earliest porcelains fall into this category. Today,hard-paste porcelain is generally made with a mixture of kaolin,feldspar,and quartz,and is now differentiated from soft-paste porcelain mainly by the firing temperature.</p>



<figure class="wp-block-image size-large is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/SevresSoftPaste-1000x925.jpeg" alt="" class="wp-image-151427" style="width:337px;height:auto"/><figcaption class="wp-element-caption"><sup>Manufactory Sèvres Manufactory French,1771–72,</sup><br><sup><a href="https://www.metmuseum.org/art/collection/search/206466" target="_blank" rel="noreferrer noopener">The MET</a></sup></figcaption></figure>



<h3 class="wp-block-heading">Soft-Paste Porcelain</h3>



<p>This type is sometimes referred to as ‘artificial porcelain’,though it is widely accepted as a genuine type of porcelain. It fires at a lower temperature of around 2200°F (1200°C),which makes it slightly weaker. The lower firing temperature does offer some benefits,however,including a wider palette of colors for decoration and reduced fuel consumption.&nbsp;</p>



<p>Soft-paste is also more granular than hard-paste porcelain,with less glass being formed in the firing process.</p>



<figure class="wp-block-image is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/image-1.png" alt="" class="wp-image-151434" style="width:284px;height:auto"/><figcaption class="wp-element-caption"><sup>Spode factory,UK,1823,<a href="https://www.britishmuseum.org/collection/object/H_1981-0101-486" target="_blank" rel="noreferrer noopener">British Museum</a></sup></figcaption></figure>



<h3 class="wp-block-heading">Bone China</h3>



<p>This clay is composed of bone ash,feldspathic material,and kaolin. It’s the strongest of the porcelains,having <a href="https://en.wikipedia.org/wiki/Bone_china" target="_blank" rel="noreferrer noopener">very high mechanical and physical strength and chip resistance,and is known for its high levels of whiteness and translucency.</a> Its high strength allows it to be produced in thinner cross-sections than other types of porcelain.</p>



<p>Bone China was developed in the UK,where factories began adding bone ash to their soft-paste porcelains in an attempt to more closely replicate the hard-paste clays of Asia. Because of this,the clay is <a href="https://en.wikipedia.org/wiki/Bone_china" target="_blank" rel="noreferrer noopener">often referred to as ‘English porcelain’</a>. It remained an exclusively British material for 200 years,before it was finally produced in Japan,then later Russia,China,and the rest of Asia.</p>



<h2 class="wp-block-heading">Porcelain Glazes and Surfaces</h2>



<p>There is a wide range of glazes and glaze processes commonly used on porcelain,from classic clears,to gold lusters,to opaque and vibrant colors. Today,we’re just going to look at a few that are more specifically associated with this elegant clay body.</p>



<figure class="wp-block-image is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/image-14.jpeg" alt="" class="wp-image-151432" style="width:436px;height:auto"/><figcaption class="wp-element-caption"><sup>Left to right: Dish,unknown maker,1426 – 35,Jingdezhen,China.<br>Dish,unknown maker,1655 – 65,Jingdezhen,China.<br>© <a href="https://www.vam.ac.uk/articles/chinese-blue-and-white-ceramics" target="_blank" rel="noreferrer noopener">Victoria and Albert Museum,London</a></sup></figcaption></figure>



<h3 class="wp-block-heading">Blue &amp; White</h3>



<p>This glaze and stain combo is probably what first comes to mind for most people when they think of porcelain. Its use actually predates porcelain,first appearing in the Tang dynasty (618 – 906),but it was when it found its way onto porcelain that its popularity skyrocketed.&nbsp;</p>



<p>Blue and white is typically achieved by brushing a cobalt stain onto the white clay,and applying a clear glaze on top. It can also be achieved by brushing the cobalt on top of the glaze.</p>



<figure class="wp-block-image is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/image-13.jpeg" alt="" class="wp-image-151431" style="width:286px;height:auto"/><figcaption class="wp-element-caption"><a href="https://spokenvision.com/the-exquisite-elegance-of-goryeo-celadon/" target="_blank" rel="noreferrer noopener"><sup>Goryeo celadon,Korea</sup></a></figcaption></figure>



<h3 class="wp-block-heading">Celadon</h3>



<p>Celadons are beautiful transparent green glazes that were developed in China and prized for their jade color. While their popularity was eventually surpassed by the aforementioned blue-and-white porcelain,these glazes are still loved by artists and enthusiasts today.&nbsp;</p>



<p>Celadons are reduction fired,and contain iron oxide to achieve their characteristic color. The celadons that are commonly used today tend to be glossy transparent <a href="https://digitalfire.com/glossary/celadon+glaze#:~:text=Typically%20celadon%20glazes%20are%20employed,cause%20the%20crazing%20often%20seen." target="_blank" rel="noreferrer noopener">whereas the ancient versions were more waxy and opaque</a>. They are commonly used over carved surfaces,where the varying depth of the glaze creates a beautiful and subtle color variation.</p>



<figure class="wp-block-image is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/image-15.jpeg" alt="" class="wp-image-151433" style="width:351px;height:auto"/><figcaption class="wp-element-caption"><a href="https://commons.wikimedia.org/wiki/File:Plates,_Nymphenburg_Porcelain_Manufactory_-_Indianapolis_Museum_of_Art_-_DSC00661.JPG" target="_blank" rel="noreferrer noopener"><sup>Hermann Gradl,Nymphenburg Porcelain Manufactory,1899.<br>Indianapolis Museum of Art</sup></a></figcaption></figure>



<h3 class="wp-block-heading">Overglaze Painting or Enameling</h3>



<p>You may have noticed that a number of the example pieces we’ve included in this blog feature highly decorated surfaces. These are achieved through a process called overglaze painting,which was developed in China and eventually spread throughout Asia and into Europe.&nbsp;</p>



<p>Overglazing can be done on different clay bodies and at different temperatures,but in the case of porcelain,it typically consists of applying a pigment mixed with fluxes onto an already glaze-fired surface,and then refiring the piece at a much lower temperature. The pigments,often called China paints,melt in the kiln and become permanent. This process allows for very fine detail and vibrant colors.&nbsp;</p>



<p>Lustres,such as gold and silver,are a type of overglazing.</p>



<figure class="wp-block-image size-full is-resized"><img src="https://staging.ceramic.school/wp-content/uploads/2024/09/plate-ashmolean.jpg" alt="" class="wp-image-151429" style="width:342px;height:auto"/><figcaption class="wp-element-caption"><sup>Porcelain plate with cobalt design,1630 - 1650 China<br><a href="https://images.ashmolean.org/search/?searchQuery=porcelain" target="_blank" rel="noreferrer noopener">Collection of the Ashmolean Museum</a></sup></figcaption></figure>



<p>As we wrap up our exploration of porcelain,we're pleased to have this opportunity to celebrate the unique nature of this beautiful clay. From its historical roots to contemporary applications,porcelain’s trademark refinement and mysterious production have shaped its enduring presence in the world of ceramics. This journey has deepened our understanding of the artistry and craftsmanship that porcelain cultivates,and hopefully it has inspired you to give this challenging material a try!</p>



<p>If you would like to learn more about working with porcelain,we have a number of workshop that will be perfect for you! To get you started,consider <a href="https://staging.ceramic.school/courses/ted-secombe-throwing-porcelain/">Ted Secombe’s&nbsp; “Throwing Porcelain,”</a> where this master potter walks you through his throwing process step-by-step. Or if sculpture is more you thing,have a look at <a href="https://staging.ceramic.school/courses/sunkoo-yuh/">Sunkoo Yuh’s “How to make a porcelain sculpture</a>,” where you can follow his process from initial drawings to an intuitive approach to working with porcelain.</p>

All blog

Understanding Ceramic Glaze Components Part 4: Colorants

The Benefits of Teaching Ceramics to Young People

5 Ceramic Christmas Projects for You to Try

Understanding Glaze Composition Part 2: Flux

How to Center Clay - A Beginner's Guide

Understanding Glaze Composition Part 1: Glass-Formers

Understanding Clay Types Part 3: Porcelain

Understanding Clay Bodies Part 1: Earthenware

Understanding Clay Bodies Part 2: Stoneware