Mosaic, halftone and mezzotint effects in Paint by Zaweba
Pixelate, Crystallise, Halftone with per-ink screen angles, Pointillism, Facet, Fragment and Mezzotint in Paint by Zaweba, and what each is good for.
Breaking a picture into cells or dots is one of the oldest graphic tricks. It hides detail, it suggests print and it gives flat images texture. Paint by Zaweba has a family of Pixelate filters for this, ranging from blocky mosaics to the fine dot patterns of printed newspapers.
Pixelate (mosaic)
The Pixelate filter, also called mosaic, divides the picture into square blocks and fills each with a single colour. It is the standard way to hide a face, a number plate or private information in a screenshot. It also makes the deliberately chunky look of retro game art.
For hiding things, make the blocks large enough that the detail truly cannot be recovered. Small blocks can still leave a face recognisable, especially when viewed from a distance. For privacy that matters, a solid filled rectangle is safer still.
Crystallise, Facet and Fragment
Crystallise breaks the picture into irregular polygon cells, like looking through crackled glass or a stained window. It makes a strong abstract background from any photo. Facet groups similar colours into flat patches, which gives a hand-painted feel. Fragment copies the picture several times with small offsets, producing a shaken, doubled look that suggests vibration or confusion.
Halftone
Halftone recreates the dot patterns of printing. Shades become dots of different sizes on a regular grid, the look of old newspapers, comics and pop art. Paint's Halftone works per ink, with its own screen angle for each, as in real colour printing, where the cyan, magenta, yellow and black screens are set at different angles to avoid unwanted patterns. Getting those angles right is what makes a colour halftone look like print rather than a grid of polka dots.
Use it on a duplicate layer and blend it back, perhaps in Multiply, for a subtle print texture. At full strength on a bold portrait, with strong contrast, you get a classic pop art poster.
Pointillism and Mezzotint
Pointillism fills the picture with random coloured dots against the background colour, like the paintings of the pointillist painters. It works best on bright, simple subjects such as flowers and landscapes.
Mezzotint turns the picture into a random pattern of dots, lines or strokes, imitating the old engraving method. In black and white it makes a grainy, vintage look, good for album covers and posters.
Getting the best from cell and dot effects
Prepare the picture first. These filters all simplify, so a picture with clear contrast gives much better results than a flat one. A Levels or Curves adjustment beforehand to strengthen shadows and highlights often helps more than any filter setting.
Consider the final size. A halftone with fine dots looks good in print but can create moiré, an odd wavy pattern, on screens. For screen use, choose bigger dots or view at 100 per cent before you commit.
Mix effects with masks. A halftone that fades out across a picture, done with a gradient on a layer mask, looks more designed than one applied evenly.
Mistakes to avoid with cell and dot effects
Do not pixelate private details on a layer and then save in a layered format you share; the original layer may still be inside. Flatten the area or delete the source layer first. Avoid resizing a halftone after applying it, since resampling blurs the dots; apply the filter at the final size. And with Crystallise and Fragment on faces, keep the strength modest unless you want the face to disappear entirely.
These filters share the live preview and Strength control of every filter in Paint by Zaweba, so you can try a few in quick succession and keep the one that fits.
