Cel Animation for the Digital Era

scooter dog painted cel

Getting Started with DIY Cel Animation

As I’ve finally settled on a workflow I like, I thought it’d be a good time to share some  tools and processes for making animation on cels. This post owes a heavy debt to Ingo Raschka’s instant classic zine offering, Making Cel Cartoons (get it!), and helpful advice from animators Josh Cloud, Georgia Reid, and Anna Firth, along with some of my own learn-by-doing experiments over the last year. Let’s begin.

Source Some “Cels”
Cels made specifically for traditional animation are thick, durable, and lay flat. They are also scarce and expensive, and the current pricepoint puts them out of reach for most animators (including myself). After some experiments, I’ve settled on using laser transparencies instead of cels. Laser transparencies are very thin and floppy, but you can print linework onto them directly in any laser printer. I buy them in generic packs of 100 off of ebay (never buy them from an office supply store — those prices are wild!).

Put On A Pair Of Cotton Gloves
Like any thin plastic film, laser transparencies will attract dust and animal hair. (Later on, during shooting, a can of compressed air will be your friend). That said, the dustiness, the grittiness, the visual anomalies and microfilth fluctuating from frame to frame is actually part of what I love about the DIY approach to cel. If you’re looking to make a cel-based gif, post, or short, you must accept its presence to a certain extent (hell, I embrace it!).

In addition to airborne particulate, laser transparencies also seem to slurp up the trace amounts of oil present on human fingertips and/or canine footpads (depending on who you live with). You’re probably not going to be inking and painting in a NASA cleanroom, but oil causes way more problems than dust, and I would strongly advise you to invest in a pair of $2 cotton gloves, especially if you’re inking by hand. Oil on the surface of your cel will prevent India ink from adhering exactly where you intend it to; ink applied on top of oil will pool into microbeads and dry with lil’ bald spots amidst your lines. Maybe this is my comic book inking bias coming into play, but I prefer my ink linework to be clean af, or at least for the ink to dry exactly as I laid it down, sans interference from oily fingerprints or palm grease smudges (this probably makes it sound like I have exceptionally dirty hands. On a microscopic level, we all do! I never paid attention to how much oil is on the surface of human skin until trying to ink and paint cels).

Punch Those Cels
Now that we’re wearing our gloves, our first step is to punch our cels with a standard three hole punch (later on during shooting we’ll use a peg bar with round pegs to keep our cels aligned). If you have access to an ACME punch and corresponding peg bar, of course that works too. Whichever you use, you must make a paper guide (e.g. with a small piece of tape that marks where the edge of each cel should sit during punching) to ensure that all of your punch holes align with each other. My punch can handle about 3 cels at once without jamming. This is a time-consuming step but important to get right if you want your frames to align.

“Sandwich Theory”

I like to think of a single finished cel as a tasty media sandwich! Two slices of bread (the ink on top, the paint on the bottom) holding onto a thin slice of savory tofurky (the cel). Now, you wouldn’t put two slices of bread on the same side of a sandwich, would you? Maybe you run with an experimental crowd, but to me that wouldn’t even be a sandwich, it’d be a cold cut relaxing on a stack of bread. I’m a few sentences in and you look really skeptical of this metaphor. The big takeaway is: the ink and the paint go on OPPOSITE sides of the cel. We ink the fronts, then paint the backs. As a result of working this way, the camera (or scanner) sees the flat side of the paint, which is smooth-jazz smooth when viewed through the cel (unlike the bumpy side of the paint, which is bumpy and casts shadows all over the place). Also, we can be a bit more carefree with our painting; since the ink lines will effectively be overlaid when viewed from the other side, we don’t have to worry about accidently painting over them.

Inking The Fronts

Recommended Inks

Black Ink for Manual Application (cel front)

For inking with a brush or dip pen, I use Black Star India ink, which was recommended to me by animator/director/generous DIY info sharer Anna Firth. It’s very opaque, and sticks to plastic surfaces beautifully. For inking with a technical pen, I use Rapidograph Universal for Paper and Film. Try to get it in as big a bottle as you can afford. The 8oz version is an investment but ends up being light years cheaper than the standard 3/4oz bottles.

Black Ink for Printed Application (cel front)

Typically I draw in black ink on paper, then scan my drawings, align the scans (stay tuned for a whole post about this), then print image sequences directly onto laser transparencies. I’ve got an entry level black and white Brother laser printer (cost = ~$100), and use the toner cartridges made for it. I only have to replace the cartridge about once every 12 to 18 months. You could also animate linework in Photoshop, TVPaint, AE, Flash/Animate or your software of choice, then export and print a png image sequence. Just make sure you’re only exporting the linework – no color! We’ll be painting that on in the next step.

One last note on printing: This probably depends on the printer model, but I’ve had better results running the cels through the manual feed tray one at a time, rather than using the regular paper tray. With my printer, dropping a stack of transparencies into the regular paper tray leads to jams and misfeeds every time.

If you printed, you’re ready to flip and paint the backs of your cels.

Drying The Inked Cels

If you inked manually, I would wait anywhere from 6 to 18 hours for your ink to dry completely. Drying time depends on the ink used, how liberally it was applied, and the temperature, humidity, and ventilation in the room where you’ve set your cels to dry.

I’ve used a blowdryer to dry some cels in a hurry, but I don’t really recommend this! If you insist on trying it, use the cool/no heat setting as hot air from a blowdryer can warp laser transparencies pretty easily. Hold the dryer at least 12″ from the cel surface to prevent the air pressure from moving the ink. Also! If you use a blowdryer, choose a relatively clean room, and dust/swiff/sweep that room first, before bringing your cels into it. You don’t want to be blowing a bunch of dust directly onto your wet ink, inviting it to be baked in and stuck to your cels permanently.

In the past I’ve laid my cels out to air dry on every surface available, including the dinner table, my desk, kitchen counter, and floor. My housemates did not love this. I got a great tip from Maija Burnett recently that you can stack a bunch of thin mailing boxes and put one cel into each — a cheap solution with a much smaller footprint! If there’s a printmaker in your life (or you are one yourself) you could use a screenprinting-type drying rack. Luxurious!

Painting The Backs

In undergrad I would buy cel paint in little 2oz squeeze bottles at Cartoon Colour — they sold a great range of colors and it dried fast. But at this point cel paint is nearly impossible to find. I’ve tried several potential alternatives in the past year, including watercolor gouache (love the opacity and broad range of off-the-shelf color options, but for me it dried a bit stiff and flaked off eventually), tempera (beaded and flaked even worse), oils (never dried!), and acrylic (slow to dry but worked pret-ty well), and screenprinting ink (my favorite — never would’ve though to try it and was very grateful for this tip from Ingo). Here are some recommendations:

White Paint for Manual Application (cel back)

I love this screenprinting ink. It’s gloopy and opaque and affordable:

Color Paint for Manual Application (cel back)

I look for screenprinting inks in whatever colors I need. Unfortunately most art stores only stock basic colors (some only stock black and white). So I supplement with cheap acrylics! Generic art store brands work fine for this. Some people swear by gouache but in my experience, at least when paired with laser transparencies, cheap gouache will start to flake in a few months. Not sure about expensive gouache, because I was scared off by the price. I will say that one friend who really knows paint, and who I asked for advice after the fact, told me to avoid the specific brand of generic art store gouache I used, so my bad results are likely specific to that brand, and not gouache more generally. Also wow, I’m halfway through the article and I still can’t spell gouache from memory!

Painting: First Pass

Ok so your cels are dry and now it’s time to paint. I must admit, as careful I am about inking, I’m much messier when I flip my dried inked cels for painting! Maybe this is because I have no formal training in painting (outside of elementary school fingerpainting, which technically does count as “formal training”), and have no clue how to “properly” apply paint. But that’s good! Because cel painting technique has little to do with painting on paper or canvas (or so I am told).

When painting cels, you’re going to want to apply in “globs” or “blobs”, also known as “dabs” or “smooshes” depending on the region of the world in which you live. Never apply with “strokes”. As in the potentially future classic DIY cel mnemonic I just made up, “strokes lead to streaks”. And we don’t want streaks; when applying paint to a transparent medium, streaks = seethrough areas where the background shows through. Maybe you’re going for that. You do you. Really. But I do think that there’s something very lovely to the eyeballs about cel paint that is thick enough to be opaque, and for that level of opaqueness to be vaguely consistent from frame to frame.

Painting: Second Pass (or “Spot Pass”)

Let your first pass dry partially (never reapply over areas that are still wet! you may pick up more paint then you put down). Then go back and do a spot pass — just a little touch up on the blank spots or thinner areas, using smaller “splorches” (aka “dots” or “stipples”). I go through all of my cels sequentially doing the first pass, and by the time I get to the end, my first cel is usually dry enough to take a second application. In my experience 45 mins to an hour is usually enough dry time between coats. You needn’t wait for a complete dry before starting your second pass — the appearance of a robust puddin’ skin on your first coat of paint should be enough!

But Wait! An Alternate Approach: One-Coat “Ketchup” Method

I’ve always applied paint in two passes, with one exception. In this one test, I applied paint in ketchup-style stacked squiggles with a tiny squeeze bottle (squeeze bottle came from the dollar section of an art store). The painting process was fun and easy, especially for someone like me who is a bit clumsy with a brush. At first blush this approach may sound faster and more efficient. It does shorten the “active time”, but overall it’s much slower; squeeze bottle application increased the average paint thickness, which lead to a drying time of over 3 days in mild Fall weather! That said, if you’ve got a drying rack and time to wait, the ketchup method TM may be right for you.

Drying The Painted Cels

As with drying after inking, you’re going to have to be patient. Waiting for the paint to dry takes much longer than the ink. Anywhere from 24 to 72 hours. After 24 hours, you can start pressing on the bumpiest, most raised parts of the paint to test for dryness. If pressing on the bumps smushes them, they’re not ready to shoot! If the bumps have dried hard, you’re good to go.

A stack of dried animation cels depicting a dog on a scooter.
The video at the top of the article uses this four-cel cycle, slid across the scene.

Shooting Your Cels

I’m going to rush through this step — there are a lot of ideas out there for DIY downshooter setups, but that’s kind of beyond the scope of this article. The gist of it is: light downshooter-style with two lights shining down from opposite 45-ish degree angles. Tape your peg bar to your work surface (downshooter base / desk / table). Tape or blue-tak down your background, then lay down your cels on top of that, and shoot them one at a time using a smartphone, or digital camera + Dragonframe. Hit each cel front and back with compressed air before shooting a frame. If you’re really worried about flickery reflections due to the floppiness of these transparencies and uneven paint thickness, you could put a small sheet of tempered glass (or regular glass borrowed from any picture frame) on top of your cel and bg, to hold them flat. This would accomplish something similar to the swing-away pressure plate found on an Oxberry animation camera stand. To be honest I don’t bother with this. Since my cels are in an IKEA hacked multiplane, there are some minor reflections already so I’m embracing it as a part of the visual style. (UPDATE: alternately, you could scan your cels. I’ve never tried this, but see Anna Firth’s recent tutorial on how she approaches animating on cels for the full details.)

Storing Your Cels

You don’t want to store your cels so the paint from one comes into direct contact with the ink of another. Instead, I’d recommend putting one sheet of tracing paper between each cel, so temperature fluctuations don’t liquify your paint and cause adjacent cels to stick together. If you can, place cels into manila folders and store them on edge. The pressure from stacking them can lead to additional sticking. I’ve also tried putting a sheet of regular copy paper between each cel. It worked pretty well, but it lead to more sticking than tracing paper. I’m curious about parchment paper, which is used for nonstick baking. I’ll update the article once I’ve tried that.

Closing Thoughts

Ultimately, going through this very difficult process myself left me in awe of the incredible skill, draftsmanship, and technical expertise present in ink and paint departments in the studio system as it existed in the mid 20th century US. Ink and Paint was staffed largely by highly skilled women artists, who were given very few opportunities in an industry which absolutely could not function without them (until layoffs driven by the development of xerography and digital paint tools, in that order, rendered them “obsolete”). The loss of institutional knowledge driven by these layoffs is staggering. Yes, very few people working today have any interest in the traditional cel process, but for anyone who is excited at its possibilities, its a chilling thing to think about. For an in-depth, eye-opening look at this story, check out Mindy Johnson’s amazing book, Ink & Paint, The Women of Walt Disney’s Animation.

What does it mean to reclaim ink and paint as an animation filmmaker? When traditionally directors couldn’t have been further from the process, whether that be due to overseas outsourcing or the unfair labeling of ink and paint as a “pink collar” job. (I guess the great exception here is the underground animation of the ~’60s-`80s). There’s something deliciously punk rock about working on cels and doing ink and paint yourself! And not caring about cleanliness in the process. Leaving in the mess-ups, the paint splatters, the accidents, the lightening flash of a blonde dog hair — of owning and uplifting analog ink and paint as something personal and important — an essential and wrongfully maligned part of the animation process.

Maybe at some point I’ll update this article with some explanatory pics. In the mean time, have fun with process and feel free to reach out with any questions or findings!

New Information!

  1. Anna Firth has written up her cel animation process, using real-deal animation cels (not laser transparencies), for the tutorials section of her website!
  2. Phoebe Parsons has written up her cel animation process (using overhead transparency film), and shared a studio tour, right here on DIY Animation Club.
  3. I recently purchased a very large lot of scene folders containing cels from a few different 1980s Saturday Morning Cartoons. These came from a generous Ebay seller who gave me a deal based on it being for educational purposes. In examining them carefully, I noticed that a lot of these cels had the ink on the *backs* of the cels (on same side as the paint). This was very surprising to me. Could this be due to a quirk of the particular studio? Could it have been an accident? Or did things change with the switch to photostat/photocopy (ie. copy linework onto cel back, then paint on top of that)? If you have any inside info, I’d love to hear it…

Recommended Viewing

A handful of favorites, all of which either were made on, or incorporate sequences that use, animation cels.


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