Using the Smudge Tool

The Smudge Tool: How to add a painted effect to an existing image

This article discusses how I've used Photoshop's smudge tool (the one that's an index finger pointing downward) to create a painted effect on several wallpapers. It does not discuss how to create a digital painting from scratch. There are many tutorials on that subject by as many artists as there are styles.

The smudge tool works really well in conjunction with an art tablet because you can utilize the tablet's pressure sensitivity to manipulate the strength of the smudging. Also, if you are comfortable using your tablet to draw, write or doodle on the screen, smudging will feel fairly intuitive. I haven't tried smudging with the mouse, but considering how labor-intensive smudge-painting a 1920x1200 image is, I can't imagine it would be good for your wrist.

Before you start smudging, you have to prepare your image. Smudging works best on an image that has some texture, half-tone dots, noise, dirt, dust or speckles, because it drags around the colors under the cursor. If you're working on a flat color, there's nothing to see when you start to smudge. This makes smudging another technique to consider for image cleanup and re-CG. Also, you should keep a copy of the original image on a locked layer. If you mess up, or want to redo a region, you can just copy it from that layer and rework it. Sometimes you can't go back enough steps in the history and even reverting won't bring you back to the state you want. Also, it helps you keep track of what areas you've worked on and where you need to go, and in the end it's fun to compare the original to the smudge-painted version.

The important thing to remember when smudging is that to get the painted effect, you need to smudge in the direction a paint brush would go. This may mean following the curves of a hand, or rolling in circles in the clouds. Use your judgement for which direction a brush's strokes would go, but there are also plenty of fine art galleries available online that you can use for reference.

Like many of Photoshop's tools, smudging makes use of Photoshop's brush engine. You can customize the brush in a large number of ways. However, for smuding you'll probably want a simple brush that changes size in response to pressure (if you have a tablet). The default round brushes with a soft edge work well, or you can use one of the media brushes if you want a slightly rougher effect.
Choose a brush size appropriate to the area you are working on. You'll want a small brush when working on the fine details on a face, but a large brush will make the job faster and smoother when working on a large area like a shirt. Remember, right-clicking will bring up the brush options box where you can change the size of the brush.
Make sure you're also at an appropriate zoom level. You want to see what you're doing up close if you're working on fine details. But be sure to pause every so often and look at the picture at 100% scale as well as looking at the entire image at once. That'll tell you if you're off in an area.
The other thing you can change with the smudge tool is its strength - how far is the color moved when you drag the cursor over it. This determines the "length" of the brush stroke, but I usually leave it around 50%. Too low (below 30%) and it takes forever to smudge, too high (aboe 70%) and it's hard to control.
If you need to smooth out a large area, try brushing first in the direction of the paint strokes, then perpendicular, then in the direction of the paint strokes again. That will help spread the colors around more quickly resulting in a smoother area. If you only smudge in one direction you'll see that you get lines - these are what create the brush stroke effect, but sometimes it's distracting.

Smudging will also create a picture that is slightly blurry. There are several ways to counter this issue. You can work on an image that is larger than what the final size will be (at least 50%-100% larger probably, but any larger may slow down your computer). You can softly overlay the original image over the smudged image - the outlines will usually come out the strongest, which is about the only part of the original you want to come through sharply anyway. A judicious use of sharpen filters may also help.

Enjoy experimenting with the smudge tool!