Choosing the right blur filter in Paint by Zaweba
Gaussian, motion, lens, tilt-shift, spin and more: what each blur filter in Paint by Zaweba is for and how to get natural results.
Blur sounds like a single effect, yet the right blur depends entirely on the job. Softening skin, suggesting speed, faking a shallow depth of field and making a scene look like a model village all call for different kinds. Paint by Zaweba has a long list of blur filters, and this guide sorts them by what you would use them for.
All of them share the usual filter dialog with live preview and Strength, and they respect your selection.
Everyday blurs
Gaussian Blur is the general-purpose soft blur. Use it for softening a background behind text, making a frosted panel or smoothing a mask. Box Blur is simpler and slightly harsher; it is quick and fine for backgrounds that will be covered anyway.
Surface Blur and Smart Blur smooth areas of similar colour while keeping edges crisp. They are the choice for smoothing skin or a noisy sky without making outlines go soft. Bilateral blur works on a similar edge-aware idea. Kuwahara flattens areas into painterly patches, which can make a photo look hand painted.
Blurs that suggest movement
Motion Blur streaks along a direction, as if the camera or the subject moved. Put it on a copy of a car or runner, mask it so the front stays sharp, and you have speed. Radial blur works outwards from a centre point. Zoom Blur gives the burst effect of zooming a lens during the exposure, good for dramatic posters. Path Blur follows a path you draw, so the streaks can curve with a road or a dancer's arm. Spin Blur rotates parts of the picture, ideal for wheels and propellers, and it has bokeh options for bright highlights.
Blurs that imitate a camera
Lens Blur is the most photographic. It takes depth from the picture's brightness, from a channel or from a separate depth image, and blurs more where things are meant to be further away. You can set the iris shape, which changes the shape of out-of-focus highlights, and boost highlights for glowing bokeh. Adding a little noise stops the blurred area looking too smooth next to the grain of the sharp area. Depth Blur works along similar lines.
Shape Blur uses one of twelve kernels, so the blur takes on a particular shape, and Disc Blur imitates a round lens aperture.
The blur gallery
Field, Iris and Tilt-Shift form the blur gallery. Rather than typing numbers, you drag handles on the preview. Field Blur varies the blur across the whole frame. Iris Blur keeps an oval sharp and blurs outwards from it, perfect for a portrait where you want the face in focus and the busy background soft. Tilt-Shift keeps a band sharp and blurs above and below, which makes street scenes and landscapes look like miniatures, especially from a high viewpoint.
Variable Blur rounds things out by changing the amount across the picture.
Getting natural results
Blur on a duplicate layer so you can mask it and change your mind. When blurring a background behind a person, select the person, invert, and feather the edge a little; a hard selection edge gives the cut-out look that gives fakes away.
Match the grain. Real photos have noise, and a perfectly smooth blurred area looks pasted in. Lens Blur's noise option or a light Add Noise afterwards helps.
Do not overdo it. Real depth of field changes gradually with distance, so a gentle increase of blur towards the far background usually looks more convincing than a uniform heavy blur.
Where blurring fits
Blur filters pair with the selection tools for isolating subjects, with masks for blending, and with the Fade command for backing off. They are among the most used tools in Paint by Zaweba, and knowing which one to reach for saves a lot of trial and error.
