Colourising black and white photos with hints in Paint by Zaweba

Old family photographs in black and white can feel distant. Adding colour, done with care, brings them closer, and many people want to try it with a grandparent's wedding picture or a street scene from decades ago. Paint by Zaweba has a way to do it that needs neither artistic skill nor an online service: you scribble colours where they belong, and the app spreads them for you.

How it works

Two commands in the Image menu do the job. Image > New Colour Hints Layer makes a layer for your hints. Then you scribble colours onto the greyscale photo on that layer: a stroke of skin tone on each face, green on the grass, blue on the sky, the colour of a dress on the dress.

Running Colourise with Hints then spreads those colours across the picture by optimisation. In plain terms, it works out the colour for every pixel so that neighbouring pixels of similar brightness end up with similar colours, while staying true to your hints. Colour flows up to edges, where brightness changes sharply, and stops there. The result goes into a new layer, so the original photo stays untouched underneath.

Placing good hints

You don't need to fill areas in; small, confident strokes are enough. One stroke through the middle of each region is often plenty.

Mark every region that should have its own colour. Where you leave a region without a hint, it takes its colour from its neighbours, which may not be what you want. Small but important areas, such as eyes, lips and buttons, deserve their own hints.

Hint the boundaries when colour leaks. If skin colour spills into a background of a similar grey, a stroke of the background's colour close to the edge stops it.

Choose believable colours. Real skin, grass and sky are less saturated than they look in memory. Muted colours give a much more natural result than bright ones. Sample from a modern colour photo of a similar subject if you're unsure.

Use neutral hints for things that should stay grey or white, such as white shirts, stone and silver. A grey hint keeps them neutral rather than letting nearby colour bleed in.

Refining the result

Because the colour is on a new layer, you have plenty of room to refine. Lower its opacity for a softer, hand-tinted look. Change its blend mode to compare how it sits on the original. Add more hints and run the command again if one area is wrong.

For final touches, a soft brush in Colour blend mode on a separate layer can adjust small areas by hand. The Sponge tool, used lightly, can calm any patch that has become too saturated.

Preparing the photo first

Colourising works best on a clean image. Scan old prints at good resolution, then use Fade Correction if the print has a yellow or brown cast from age, and clean up dust and scratches with the retouching tools. A clean, even greyscale image gives the optimisation clear edges to work with.

If the original is a colour print that has faded rather than a true black and white, Fade Correction alone may be enough to bring back its colours, and colourising may not be needed at all.

A note on accuracy

Colourised photos are an interpretation. Unless you know the colours, of a uniform or a car for example, they're your best guess. When sharing a colourised family picture, it is worth keeping the original black and white version with it.

Everything happens on your own computer in Paint by Zaweba, so precious family photos never leave it.