Fluid Warp, the liquify tool in Paint by Zaweba

Fluid Warp is the liquify tool of Paint by Zaweba. Instead of bending a layer with a box or a grid, you push the pixels around with a brush, as though the picture were printed on something soft. Filter > Fluid Warp, or Ctrl+Shift+X, opens it in its own window.

Its own window

Fluid Warp works in a separate window with its own tools and settings. That keeps things clear: you go in, reshape, and come out. Everything you did in the window counts as one undo step back in the main editor, so if you do not like the whole result, one undo removes it.

The tools

Forward warp is the main one. It pushes pixels in the direction you drag, like nudging wet paint with a finger. Use it to tidy the line of a garment, reshape a wave of hair or straighten a wobbly edge.

Reconstruct paints the picture back towards its original state, gradually. If you have pushed too far in one place, brush over it with Reconstruct rather than starting again.

Smooth evens out bumps left by heavy pushing.

Twirl clockwise and twirl anticlockwise spin the pixels under the brush. They are more for creative effects than for corrections.

Pucker pulls pixels in towards the centre of the brush, shrinking what is under it. Bloat pushes them out, enlarging it.

Push left moves pixels sideways relative to the direction you drag.

Freeze paints a mask over areas you want to protect, and thaw removes it. Freeze is the most important tool for natural results; it stops your warp from dragging along nearby things that should stay put.

Brush settings

Size, density, pressure and rate control the brush. Size sets how big an area is affected. Density decides how the effect falls off towards the edge of the brush. Pressure sets the strength. Rate sets how fast the effect builds up when the brush is held still.

As a starting point, use a large brush with low pressure. Large brushes make smooth, natural changes; small brushes make lumps.

Seeing what you are doing

You can show the mesh, the mask and a backdrop. The mesh shows how the picture is being bent, which helps you see whether changes are smooth. Showing the frozen mask confirms what you have protected. A backdrop lets you see other layers behind the one you are warping, which helps when you are matching something to its surroundings.

Reconstruct All and Restore All are there for when you want to undo most or all of what you have done inside the window.

Meshes save as .ptmesh files. A mesh is the record of how the picture was bent, so you can apply the same warp again later, which is useful for consistent changes across a set.

Using it responsibly

Liquify is often linked with unrealistic body editing. Used lightly, it is a tidy-up tool: straightening a crease, evening out a hem, fixing a lens bulge at the edge of a group photo, or giving a product's outline the clean line it really has. Heavy changes to people tend to look wrong and can leave bent backgrounds.

Common giveaways

Warped backgrounds, such as bent door frames or wavy tiles behind someone, are the classic sign. Freeze the background first. Small brush lumps are the other; use a larger brush and Smooth.

For faces in particular, Paint by Zaweba has a face aware mode inside Fluid Warp, which is covered in its own article.