Back to Class! Tips from Winterthur’s “Ceramics Up Close” Conference

Sharpen your pencils and put your thinking caps on… we’re going back to class!  Here at NMSC, we try to attend conferences and workshops on a fairly regular basis in order to keep abreast of the latest research and network with other museum professionals.  Last month, I attended the 2017 Ceramics Up Close conference at Winterthur, which allowed me to get an in-depth, hands-on look at some of the remarkable ceramics in Winterthur’s collection (ALL of which are digitized on their online database!).  There is truly no better way to learn about these objects than to see them up close, front and back, and discuss them firsthand with experts.  The tips I learned at this conference will help me to better catalog and date the ceramics we encounter in NPS archeology collections.  We hope they will help you, too!  If you work with historic ceramics (or pieces of them, like we do), or just enjoy them, for that matter, then this blog post is for you!

bartman

NMSC’s Jessica (author) at Winterthur’s 2017 Ceramics Up Close conference.

 

Is it Chinese export porcelain, or an English imitation?

In the 18th century, English porcelain factories like Bow, Caughley, and Spode produced soft paste porcelain to try to imitate the hugely popular hard paste variety coming out of China.  (There’s a great online exhibit about Spode – and the Chinese export it was inspired by – accessible via Winterthur’s website.)  Sometimes it can be hard to tell the difference!  Here’s a helpful tip I learned:  the Chinese never printed on their wares, while the English did.  If it looks like blue and white Chinese export but it’s printed, it’s probably English.

final for blog

Left:  Chinese export porcelain plate, handpainted, Winterthur collection.  Right:  Spode soft paste porcelain plate, printed, Winterthur collection.

Is it slip cast, or press molded?

Slip casting was a popular method of producing fine stoneware vessels in the mid-18th century.  It was not often used with earthenware, and was less common after the 18th century.  The fairly complicated process of slip casting resulted in the molded decoration being echoed in relief on the interior of the vessel.  If you can feel or see the reverse decoration on the inside of the piece, it was slip cast, and most likely dates to before 1800.  If the interior is smooth, it was probably press molded.

teapot 1740-1760

Slip-cast white salt-glazed stoneware teapot in the museum collection at Winterthur.

Is it majolica, or is it faience?

(We’ve noticed some differences in opinion throughout the field as to exactly how you define and identify these tin-glazed wares.  The tips offered here represent what I learned at this conference.  If you have a different opinion, we encourage you to share it with us!) 

I learned at this conference that majolica vessels were sometimes finished with less expensive lead glaze on the back (like the vessel shown here), while faience was usually completely tin-glazed.  Also, majolica pieces may exhibit “crows feet” – marks from the separators used to create space between vessels during firing.

tin enamel with lead glazed back

Tin-glazed plate with lead-glazed back from museum collection at Winterthur.

crows feet

Close-up showing “crows feet” on above vessel.

How old is that tin-glazed vessel? Where was it made?

We learned at this conference that manganese wasn’t used until about 1650.  In a nutshell, if you see manganese, it’s mostly likely about 1650 or later.  We also learned that Portuguese tin-glazed vessels often have this pin-pricked look to their glaze.  If you see a bunch of tiny holes like this in the glaze, there’s a good chance it’s Portuguese.

portugal plate front

Tin-glazed plate with manganese outline from museum collection at Winterthur.  Portugal, ca. 1650-1675.

portuguese plate pin pricks

Back of the above plate, showing pin-prick-type holes in the glaze.

Is that stoneware from Germany, or somewhere else?

German potters separated their vessels from the wheel by cutting them off at the base with cheese wire, resulting in rough, somewhat parallel ridges on the base like the ones seen here.  English and Dutch potters removed their vessels from the wheel by simply lifting or pulling them off.  Instead of the ridges, you’d see what might be described as pucker marks on the bases of these vessels, or they may look fairly smooth.  If you see ridges like this on the base, it’s probably German.

stoneware base

Base of a stoneware vessel in the museum collection at Winterthur.  Note the ridges created when the vessel was cut from the wheel.

Is that Chinese porcelain or Japanese porcelain?

Both Chinese and Japanese 18th-century porcelain was sometimes decorated in this specific color palette of burnt orange, gold, and blue, sometimes referred to as the “Imari palette.”  How do you tell if a vessel like this is Chinese or Japanese porcelain?  The Japanese decoration was often “busier,” as seen in the difference between these two plates.  Also, Japanese ceramics show evidence of the kiln furniture that separated one piece from another during firing.  (Look closely; click on the photo to enlarge it a bit.  See the three circular marks on the back of the first plate?)  You will not see these marks on Chinese porcelain.  So, if it’s “busy” and has marks in the glaze from kiln furniture, it’s probably Japanese rather than Chinese porcelain.

japanese kiln marksboth

Japanese plate with “Imari palette” from museum collection at Winterthur.  Kiln furniture marks evident on back of plate.

chinese imari front and back

Chinese plate with “Imari palette” from museum collection at Winterthur.

 

These are just a few of the tips I came away with from this fantastic conference.  During our work with NPS archeology collections, we regularly come across familiar friends like feather-edged pearlware plates, transfer-printed whiteware teacups, and lead-glazed redware jars.  We also see our fair share of vessel forms and decorative techniques that throw us for a loop!  These challenges are what make our jobs fun and exciting.  Taking advantage of learning experiences like this helps us stay up to date in the field, hone our cataloging skills, and better understand the wonderful world of historic ceramics.

 

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About JessicaC

Jessica is a Museum Specialist in the Archeology Program at the Northeast Museum Services Center/National Park Service. She majored in history as an undergraduate at the State University of New York at Geneseo, and has a master's degree in historical archeology from the University of Massachusetts-Boston. She is particularly interested in 18th and 19th century American history and material culture.
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