From Paper to PDF: Vectorizing Hand-Drawn Artwork with Photoshop and Illustrator

I have a close friend, Mike Manoogian, who is a brilliant lettering and logo design artist. Every so often, we get to collaborate on a book cover or an identity program, and have way too much fun. Despite our similar tastes and sensibilities, we live in separate design worlds: I’m the computer-savvy Photoshop, InDesign and Illustrator ninja; in his world, “cut and paste” involves an X-Acto knife and rubber cement, and his MacBook is strictly for email. We make a good team.

A little while back, Mike got a call from the Lawrence Anthony Earth Organization—a non-profit founded by the late Lawrence Anthony, the famous “Elephant Whisperer.” They needed a logo for a new ecology-centered education program that was already on the launch pad. Could he help? Rush? Of course he could. Could I turn whatever he came up with into a multi-purpose vector file really, really fast? Of course I could.

The first rough wasn’t for vector conversion, but was enough to get all concerned excited about the idea: the Vitruvian man in the negative space within a collage of living things. My work started with the first “serious” sketch. Meticulous inking wasn’t an option, given the time constraints, so the digital tools at my disposal were going to substitute for a tech pen, stat camera, and time. Mike sent me a 600 ppi scan of an outline version. Here’s what one part of it looked like at 100% in the original grayscale image:

Scanned Image

“That’s a challenge,” I thought. But it wouldn’t be a major problem for Photoshop and Illustrator in combination. Because the finished product needed to retain a slightly rough-hewn look, I need to clean things up without making the final vector version look too polished. Tracing with the Pen or Pencil tools was out of the question. There wasn’t time, so Adobe Illustrator would have to do the heavy lifting with Image Trace.

First stop, Photoshop

The first step in Photoshop was to clean up extraneous marks, smudges, and visible cut edges of tracing paper—easy enough using the Spot Healing brush and the venerable “Dust and Scratches” noise reduction filter. Next was a Levels adjustment layer, to make the darks black, the mid-tones dark, and any leftover light smudges invisible.

Layers Adjustment in Photoshop

Note where the sliders ended up in the histogram. Bringing the left (blacks) slider toward the middle ensures that any pixels to its left turn completely black. The middle (gamma) slider alters the mid-tones: move it to the left and they lighten up; to the right and they darken. The highlight slider is your friend any time you have to get rid of any light grays that shouldn’t be in the final image.

Illustrator and Image Trace to the rescue

It’s still looking rough, but that’s okay; it’s nothing that Illustrator can’t handle. I imported the PSD directly into Illustrator, choosing to flatten the PSD into a single image because the layers aren’t needed.

import_options

The result is an embedded raster image at the full resolution of roughly 4600 pixels square, which Image Trace will turn into vector art. When you run Image Trace on something this size, Illustrator will complain that it is rather large, and suggest that you reduce the size to help things run faster.

Illustrator gives dire warning of slowdowns ahead

The problem with doing that is you run the risk of individual pixels being outlined as visible blocks, destroying the organic look of the original, but unless you’re running Illustrator on a very out-of-date or low-powered system (and why would you do that?), the trade-off is seldom worthwhile. In this case, the speed penalty is minimal.

The “Sketched Art” preset in Image Trace looked like a good starting point. Here, though, it did too thorough a job of simplifying and smoothing the outlines, which would destroy the organic character of the logo when it’s displayed at larger sizes. (Note that the “Advanced” settings are toggled open and “Ignore White” is checked. This is important. It will make the background transparent rather than opaque white in the vector result.)

The Sketched Art preset does too thorough a jobThe Advanced settings are the key to getting the result you want from Image Trace. Every piece of art is different, and while the built-in presets may get you most of the way there, most of the time you’ll want to fine tune the results. Let’s break it down.

The “Threshold” slider works the same way that the Threshold adjustment works in Photoshop. The grayscale (luminance) levels run from 1 (anything not completely black) to 255 (pure white). Any pixels below the level you set will be turned black, and anything lighter will disappear. This artwork has some important grays that are higher that 128, so that slider will have to go a bit to the right.

“Paths” regulates how many paths will be in the final vector image. It does this by averaging out the changes in direction in the pixel outlines, so a high number sticks to the edges exactly (producing more paths), while a low number gives a smoother result that is less faithful to the original. In order to keep the rough-hewn look, this number will have to increase.

Here is a capital A in the font Arid, which I’ve screen captured and pasted into Illustrator. In the Image Trace panel “View” is set to “Original Image.” You can see the pixilation at the edges:

Rasterized Arid A

With Paths set to 10%, the outline changes significantly. The real “A,” as a type glyph, is below the trace for comparison:

Paths is set to 10%

If we set the Paths at 90%, the result is much more faithful to the original. (In case you’re wondering, 100% is almost never a good idea. Those edge pixels will turn into paths, giving you a “pixelated vector file”—probably not the result you want.)

Paths at 90%

Notice the three orange dots to the left of the stroke. They would be missing entirely from this trace. We’ll fix that shortly.

“Corners” controls how abruptly the direction of each path is allowed to change. In the screen shots so far, this parameter has been at 100%. Let’s reset Paths to the default 50% and see what happens with Corners set to 0%. Notice the rounded angles where I’ve indicated.

Corners at 0%

And what is this “Noise” slider all about? Image Trace allows you to ignore details smaller than a certain number of pixels, on the assumption these are “image noise” and not relevant to the tracing process. Remember those dots showing through in orange from the original character? At a default 25 pixels, the Noise setting ignores them completely, but if we slide Noise over to 1 pixel, it turns off. Now those dots will be in the trace:

Noise Off

In the logo trace, I wanted to throw away random dots, fill in any gaps in the outlines, but keep the rustic character of the sketch. I had to retain enough detail to give that rough-hewn look at large sizes, but not so much that details would break apart or look fussy on a business card. Here are the settings I ended up with:

Custom Trace Setting

After converting the trace to solid objects, here’s how the final result appears.

Final Artwork

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Posted on: December 16, 2016

Alan Gilbertson

Alan Gilbertson is an independent (Scots by birth, independence is in the blood) creative director and designer living in Los Angeles, on the left coast of the U.S. Specialties are visual branding, identity programs and large format (indoor, outdoor and illuminated), across all media. His first love is book design, which he never gets tired of, closely followed by Creative Suite workflow efficiency, with which he is mildly obsessed. Besides CreativePro, you can find him on graphicdesign.stackexchange.com , Behance, InDesign Secrets, various Adobe forums and a sprinkling of social media sites such as LinkedIn, Twitter (@gngcreative) and Google+ (+AlanGilbertson), sharing hard-won experience with Photoshop, InDesign, Illustrator and other apps in the Adobe Creative Suite, most of which he uses (although InDesign is still his favorite).

3 Comments on From Paper to PDF: Vectorizing Hand-Drawn Artwork with Photoshop and Illustrator

  1. Very illuminating, great post

  2. I’m learning Photoshop and Illustrator and it’s been quite a hard experience. Thanks for sharing some nice tips here.

  3. Wow, what a beautiful illustrations! This post has motivated me to learn more..thanks

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