If you’ve ever seen an image where someone’s arms look a little too thin, breasts a little too large, or eyes the size of golf balls, you’ve probably experienced Photoshop's Liquify tool used poorly. You’ve likely seen its use in countless other images as well — but you won’t have noticed. Liquify can be used for the powers of good as well as evil, to make subtle and undetectable changes to images; it’s a key retouching skill.
I’ve used a photo of myself here, but use any portrait shot you have lying around.
The Liquify tool is an old-school feature in some ways: it’s destructive, and it only works on one layer at a time, in an RGB image. Use Image > Image Mode > RGB if needed. For safety, duplicate your layer by right-clicking and choosing Duplicate Layer.
With your duplicate layer selected, choose Filter > Liquify, or press Command-Shift-X. You’ll see a selection of tools on the top left side of the window that appears, and a selection of many parameters on the right, the most important of which is Tool Options.
The default tool is the Forward Warp tool, the one that looks a little like the Smudge tool at the top of the panel. Essentially, dragging with this tool pushes part of the image around in a natural way. The default settings should be suitable for a quick smooshing around of the image — you could try making the ears more “Vulcan” by pulling them out a little. Push the ends of the eyebrows up for the full look.
You can also make any feature smaller or larger with gentle nudging. Use a larger brush and lower pressure with repeated strokes for a natural result.
This tool will let you enhance a smile, raise an eyebrow, and (of course) thin a body part. Use with caution.
When important parameters like Brush Density and Brush Pressure are too strong, it’s like finger painting: a disaster. Keep those settings low, and vary brush size as needed. You can use [ and ] to change brush size quickly; hold Shift to change faster.
Inevitably, you’ll take things a little too far. Luckily, there’s an easy fix. Hold Option as you paint with the Forward Warp tool, and reality paints itself back in gradually. You’re getting quick access to the Reconstruct Tool, and it’s ideal when you make eyes just a little too wide or a nose a little too small.
The fifth tool down is the Bloat tool, that makes things bigger. Yes, this can make breasts slightly larger. It’s also the way to give anyone “alien eyes”. Holding Option gives you the opposite: the Pinch Tool, which you can use to make anything smaller. Try really large brush sizes (many hundreds of pixels across) to disguise your work, and use small repeated applications as before.
Note: it’s still easiest to undo by using the Forward Warp tool with Option held down.
There are a few more tools to let you Twirl, Push, Mirror and more. Give the twirl a go to enhance eyebrows, for example, and hold Option to twirl the other way. Still, the best tool remains the Forward Warp, and that’s where you should practice the most.
There are a few more controls available here, which let you paint masks to protect parts of the image, and to give you finer control over the way in which the reconstruction occurs. However, the most fun is in simply pressing OK, then flicking between before and after by clicking the visbility eye on and off in the Layers panel.
When you press OK, you apply all your changes and flatten them down. If you want the freedom to tweak later, Save the Mesh first. You can then Load it back on a copy of the original image, then continue to work on it. And what’s this Mesh business? Rather than just squishing pixels about, Liquify lays a mesh over the image. Your tools affect the mesh, and the mesh pushes the image around.
Liquify is a very neat trick — but use its power wisely. You don’t want to end up on Photoshop Disasters, do you?