Munsell & loupes: an inside look at ceramics
You can't learn everything about a ceramic fragment at first glance.
In fact, a huge chunk of an artifact's story isn't what it looks like, but what it's made of. When we don't have the full picture of where an artifact or group of pottery comes from, looking deeper into ceramic fabric (the clay and its contents) can give us some insight.
Part of the goal of an archaeological excavation is placing a site within the context of the wider world at its time. Knowing where ceramics on a shipwreck came from can help us to determine where the ship might have stopped to pick up cargo, or where passengers or crew members came from. Ceramic forms from multiple places across the Mediterranean can be similar, so the type of clay used in a ceramic vessel may provide additional clues about origin.
Visual analysis is the first step. Examining the color and components of even the smallest sherds may seem like an easy feat, but after identifying 20 fragments as "red" or "having quartz inclusions", each color begins to bleed into the next and each tiny stone under a magnifying loupe begins to look the same.
The most amazing color-matching tool in a ceramicist's arsenal is the Munsell soil color book. Imagine it as a book of paint swatches, but for identifying the color of clay. It is important for the standardization of descriptions of ceramics so that other archaeologists and researchers can read one and know exactly what the writer meant by "red". A Munsell description is more than just "red"; it might be 2.5 YR 4/6 (an orangey-terracotta red). Specificity is key!
Ceramics are made up of more than just clay from the earth. When they were made, craftspeople would toss in other bits of stone and sand to create the texture and strength that they wanted. Different types of inclusions are helpful in different kinds of ceramics—from amphoras, to commonwares and cooking pots, to finewares.
The tiny inclusions in ceramic fabric that we're interested in can't be seen very well with the naked eye, so we use a loupe (a small circular magnifying glass) to study them. With the loupe we see that what looks like plain old brown clay is actually brimming with black, red, orange, yellow, gray, and quartz inclusions! Inclusions can tell us that our ceramics come from a site where craftspeople, say, mixed yellowish brown clay with a large amount of gritty sand. With some comparative research, we may learn where this mixing happened.
The key is just to look a bit closer!
Munsell collages by artist and sound engineer Chad Yenney: https://munsell.com/color-blog/soil-color-chart-collages-interview-chad-yenney/