Scanning and printing in 3D has many applications to the world of archaeology and one of the greatest is its utility in public archaeology demonstrations. However, because plastic models are usually printed in one solid color and are mostly hollow to speed up the printing process, the result does not look or feel much like the original artifact beyond its general shape. To remedy one of these disadvantages, we paint 3D printed models at the University of West Florida. We do this to make the artifact look more realistic and to create a more intimate relationship between the viewer and the artifact. By painting plastic artifacts, we allow the viewer to better understand the object and how it looked during use, after excavation, or following conservation.
After I started painting models at the Virtual Curation Laboratory at Virginia Commonwealth University, under Dr. Bernard Means, I began 3D printing and painting for Dr. Kristina Killgrove and the Archaeology Institute at the University of West Florida. Along with some other graduate students, we have painted various types of artifacts from different sites, including hominin and animal bone. Below is a list of equipment needed for painting and some tips I have found useful throughout my experience. Additionally, I have included a step-by-step guide to painting, using an olive jar neck sherd from the Luna site.
- A variety of brushes. Ideally, you want as many different types of brushes as possible so that you can re-create as many different patterns as possible. I suggest using any variety of skinny, round tip brushes, flat tip brushes, fan brushes, and angled tip brushes in small and large sizes. You will need the skinny, small brushes for detail and the larger flat tip brushes for larger surface areas. I suggest buying a variety pack of 20-30 brushes on Amazon and experimenting with those.
- Acrylic paint. My favorite brand to use is Liquitex Basics. If you are not sure what colors you will need, I suggest buying either the 24- or 48-pack of acrylic paint and seeing which colors you use the most. Or you can buy the 4oz tubes of the colors I have found I use the most (I have never needed the hot pink to paint a plastic model):
- Yellow Oxide, Titanium White, Burnt Sienna, Ivory Black, Red Oxide, Burnt Umber, Raw Umber, Raw Sienna, and Unbleached Titanium
- Paper plates and cups (or whatever you have at your disposal) for palettes and water cups. I usually use a paper plate as my palette and reuse it as much as possible. I do the same with a water cup and paper towels.
- Fixative (optional). I have never had a problem with paint wearing off a plastic artifact. However, if you know the object will be handled a lot, it might be useful to buy a can of spray fixative, which sets the paint and prevents it from rubbing off. Alternatively, hairspray can work as a cheap fixative if you’re in a bind.
- An open mind! I love painting plastic models because it combines my love of art and my love of the past. I was an art student for one semester, although I was planning to major in photography, not painting. This experience has been useful but is absolutely not necessary. I never thought of myself as a painter (and I still don’t) but keeping an open mind allows me to be more confident in my painting. So do not be afraid to mess up or try new techniques! The worst that can happen is that you have to paint over it and try again.
Tips & Techniques
Below are some tips and techniques that I have found useful through my experience. These are only suggestions and it would be a good idea to experiment and see what works best for you!
- I like to paint each object with one coat of Unbleached Titanium. This is an cream color that works as an excellent base coat by covering up the original plastic color and allows the following coats to be richer in color. It is not totally necessary, but if I accidentally miss a spot while painting, this base coat provides a more natural color (depending on the object, of course) rather than solid black, white, or gray, which are usually the colors that I print in.
- Use different painting techniques! For example, I prefer to dabble rather than paint one even coat all over the object. Dabbling provides texture, which is absolutely necessary when representing artifacts. For example, dabbling helps to create the porous texture that most ceramics have and also adds an extra dimension to the object. Other techniques include washing, dry brushing, and stippling. For more info on painting techniques, check out this blog.
- Let each coat of paint dry, especially the first coat! Layering the colors is much easier if each layer is dry. This prevents two or more paint colors from mixing and allows you to keep the texture of the object exactly how you want it. Plus, it makes for a less messy painting experience…or, at least, it helps.
- Do not be afraid to mix paint to get the exact color you need. Sometimes the exact color we need to use does not come straight from the tube. For example, to get the perfect brown, I sometimes have to mix lighter shades in with darker shades, or add red, yellow, black, or white to get the tones right. Do not be afraid to experiment!
- Use one color at a time. What I mean is, focus on one or two colors on the object and paint those all at once. This makes it easier for you to maintain the same colors throughout the object, especially if you had to make a custom color. This way, you don’t need to remember the exact ratios and colors.
- Always use a clean brush whether it’s brand new or just washed. Accidentally mixing your last color with your newest color can mess up your work.
- If you are painting ceramics that have a glaze over the artifact, I suggest using glue as the final step to create a shiny surface that mimics the glaze.
- Do not be afraid to mess up! The best thing about painting is you can always paint over anything you do not like. Painting is very forgiving because no matter how many times you feel you may have messed up, you can always re-paint!
Depending on the artifact, painting can take a few hours. Overall, 3D scanning and printing can be a tedious process that is only lengthened (but greatly enhanced!) by painting. Scanning an artifact can take anywhere from 30 minutes to an hour and a half. Printing is the longest step that could take up to several hours, depending on the size and complexity of the model. The olive jar neck sherd, that I will walk you through next month, took approximately an hour to scan, an hour to print, and 30 minutes to paint. While these processes can be time consuming, they greatly enhance the public’s experience with archaeology!
I hope this painting tutorial helped give you some tips, tricks, and ideas for painting plastic artifacts in your very own lab! I would love to know what you think, so please feel free to leave any questions or comments!
Mariana Zechini is a graduate student at the University of West Florida. She received her B.S. in Anthropology at Virginia Commonwealth University in 2014 and has four years of experience in 3D scanning archaeological materials. Her thesis focuses on analyzing stable isotopes from human remains from a medieval cemetery site in Berlin, Germany.