Interview with Medical Illustrator, Peg Gerrity

May 15, 2017 at 12:08 pm by nickcharles

Peg Gerrity is a Certified Medical Illustrator with over 25 years experience in the field, creating striking, accurate visuals for legal, healthcare, and pharmaceutical markets. As a professional artist with an advanced education in Biomedical Science and Visualization, her work has appeared in everything from printed brochures, to posters, animation, and even mobile apps. Her pregnancy images have been leased to state and federal health departments, as well as featured on I had the great opportunity to speak with Peg about her work, her artistic process, and learn more about the importance and impact of the fascinating field of medical illustration.

Tell us a bit about your background and education.

I have a B.S. in Biomedical Science from Texas A&M University, and a B.A. in Art (Painting) from the University of Alaska. My graduate degree is a Master's in Medical Illustration from the Dept of Biomedical Visualization at the University of Illinois, Chicago.

When did you realize your passion for art, and what originally sparked your interest in the field of medical illustration?

I was always drawing or painting or creating 3D art as a kid. There's honestly not a time in my life that I can remember NOT doing art. Heading off to college though, I mistakenly believed I could never make money as an artist, so I pursued my second passion, which was life-science/medicine. While in the pre-vet program at A&M, I was drawing the life-cycles of various animal parasites in elaborate chalkboard dioramas when my professor suggested I consider Medical Illustration. This was a career I'd never heard of, but once I began researching it, I was hooked! These days, I speak to high school students (and their parents) about ways in which they too can make a career (and money) in the arts. Most parents are so proud of their artist children, but they're fearful for their futures and need to hear from professional artists that art is indeed a sustainable pursuit.

As a medical illustrator, what does your work entail?

Medical Illustrators are all about communicating complex scientific information in clear, beautiful ways. Sometimes I'll create images of surgical procedures that are used to teach doctors specific techniques. Other times, I'm creating images of fetal development for mobile apps that new moms can use to track their pregnancies. Regardless of who the audience is, my work has to be anatomically accurate, but I also have to know when to simplify things, or use color, style, and design so as not to overwhelm patients.

What tools or software do you use in your work?

I still do my initial concept sketches by hand in pencil on tracing paper. There's something about the tactile nature of sketching that gets my creative juices flowing. Then I use a mix of traditional brush and ink or paint with Photoshop. I leave as much of the art in layers as possible so that I have the ability to animate those layers in After Effects if needed.

I imagine it depends on the project, but what is your artistic process typically like?

It definitely depends on the project, so I'll use this image of the stem cells in the bone marrow as an example. If you've ever seen the marrow of a beef or chicken bone, you know it looks a bit like a sponge, and its porous spaces are called 'trabecular' bone. Now imagine all sorts of cells and vessels peeking out among those little spaces. Illustrating the ultrastructure of life on this level can be great fun because the landscape that exists within our bodies is super cool (think "Fantastic Voyage"!).

Stem cells in bone marrow (final image to the client).
Copyright Peg Gerrity

For the preliminary art, I started with several thumbnail pencil sketches. These were quite small, maybe 2 to 3 inches, and I just brainstormed various ideas on a tiny scale to see which design or concept felt the most dynamic. There are no bad ideas at this stage, as I'm just trying to keep the creative juices flowing in all sorts of directions and have a bit of fun with it. This is my favorite part of the process. I made notes of the different types of cells and structures in the margins of my strongest design.

Stem cells in bone marrow (preliminary thumbnail sketch in pencil).
Copyright Peg Gerrity

I eventually took this thumbnail to a more polished stage using Photoshop layers. Each main element in the background is sketched and scanned as a layer so that I can move things freely in Photoshop. In the sample I sent to the Client, the bone marrow in the background is on one layer, while the vessels and cells were all created start to finish in Photoshop on their own layers. Because there are so many different types of cells in the bone marrow, I added color to the preliminary sketch so that the Client could easily identify each cell.

Stem cells in bone marrow (early sample presented to the client).
Copyright Peg Gerrity

Do you have any tips or advice on tools or software?

I prefer Photoshop simply because my first love is traditional 2D painting, and I enjoy blending scans of traditional work with the software's digital techniques. My daughter, however, has always been a 3D artist, so she prefers 'sketching' directly on the computer using ZBrush. She'll either animate the models later or bring stills into Photoshop for some very cool effects.

Are there any particular artists/illustrators whose work inspires you, whether or not they are in the same field?

C. F. Payne and Tim O'Brien are two of my very favorite commercial illustrators. They are both traditional illustrators who are incredible at drawing the human figure: Chris in delightful caricatures, and Tim in a more photorealistic manner. Tim's piece for the Feb 27, 2017 issue of TIME is nothing short of amazing, and the fact that the actual portrait itself is tiny, just slays me!

On your website, you have a wonderful, dedicated section on pregnancy images. Is this a favorite area? Any other areas you particularly enjoy?

I do love drawing babies, but my other favorite area is histology. That's why the earliest weeks of pregnancy are the coolest for me to illustrate, because the embryonic cells are changing dramatically every moment.

Copyright Peg Gerrity

What do you feel is your favorite, or most important work?

The most humbling experience I've ever had was being overseas in Singapore and finding out that the moms there were using the babycenter pregnancy app featuring my images. It made me happy to know that my work has impacted women across the globe. I'm currently creating new pregnancy sets featuring moms of various ethnicities that I believe will be especially important. One set, in particular, will be used in Africa by healthcare volunteers as they guide local women through their pregnancies.


What do you consider to be highlights of your career thus far?

The absolute highlight of my career was seeing my daughter Melanie Connolly join the field of Medical Illustration. Melanie is a whiz with ZBrush and specializes in 3D models and animation. Together, we opened Chicago Medical Graphics to offer clients the option of both 2D and 3D biomedical visualization.

What do you like most about what you do?

My favorite part is researching new scientific breakthroughs and flipping through medical texts while sketching little thumbnails. I love reading up on all the science and trying to distill it into a single sketch or animated concept that tells a story.

What do you find most challenging?

The most challenging and depressing part of my job is dealing with people who steal my images from the internet. Sometimes, they do it not realizing it's the same as stealing a car or a jug of milk. Others pirate art habitually, using the images for monetary gain. In the case of my fetal images, the worst infringers steal the art for political purposes. This is particularly egregious, as I've done a lot of pregnancy images for the state and federal departments of health, with whom my contracts specifically state that the images will never be leased to political groups.

What is a common misconception people have about what you do?

As with so many illustration careers, non-artists often assume you don't have to be able to draw anymore, because 'it's all done by computer'. The computer is just another tool, similar to the airbrush that was all the rage in the 1970s. If you can't draw or don't have solid design skills and the ability to tell a visual story, it doesn't matter how much money you throw at a software program. For BioMedical Illustration and Animation, you also have to know the science and be able to communicate it clearly.

Is there a particular example of where you most felt the impact of the work you do?

I'm most proud of the patient education images and posters I've created for public health campaigns. I'm especially grateful that my art is used to help educate people in third-world countries on matters of general health, pregnancy, asthma, diabetes, heart disease, etc.

Do you have any goals for the future, or a dream project you'd love to take on?

My dream project would be to create an interactive museum exhibit featuring the stages of human fetal development, from conception through birth, and using models of various ethnicities.

Do you have any tips or advice you would offer someone considering medical illustration as a career?

Getting accepted to one of the few graduate programs in Medical Illustration can be tough, but if you love life science and art, it's worth the effort. If you're in high school or undergrad, it's a good idea to take as much life-drawing as you can, along with biology and anatomy. Check out the Association of Medical Illustrators at to find a list of the accredited programs along with recommended pre-req courses. If you'd rather draw plants, animals, and bugs, then take zoology classes and consider the Guild of Natural Science Illustrators (

What do you feel makes a good medical illustrator?

As with all freelance illustration, it's important to take deadlines seriously and be service-oriented. Often art directors and even some editors do not fully understand the science behind a project, and that can be intimidating to them when their end client is a physician or biotech company. I spend extra time on the phone or sending thumbnail sketches with call-outs that talk them thru what's happening on the cellular or anatomical level, so they feel confident when pitching my concept art to their client. I've kept numerous clients over 30 years simply by being accessible in this way and by meeting deadlines.

When not hard at work, what do you enjoy doing?

I love traveling and snapping great photos to use as references for oil paintings. I've lived overseas, and have been lucky enough to visit all 7 continents. I also enjoy golf, long walks along Chicago's lakefront, and playing classical guitar.


Nick C Sorbin (Nick Charles) is a former Managing Editor of 9 years for Renderosity's CG Industry News. By day, a mild-mannered Certified Pharmacy Technician working in both home infusion and a hospital ER, contrasting creative outlets as a digital artist, sculptor, musician, singer/songwriter, and Staff Writer for Renderosity Magazine. Read his articles

Sections: Artist Spotlight

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