In Affinity Photo, layers can change how an image looks by building on top of it without affecting the original data. has gained a new layer called ‘(Black & White Adjustment)’. Clear the check mark to its right and the adjustment will be disabled. You can create multiple adjustment layers and either blend them for new effects, or make different treatments for the image within one file.
Next, add some grain. We’ll use a live filter layer to create a layer of grain that can be infinitely adjusted. Pick Layer > New Live Filter Layer > Add Noise Filter. To keep things photogenic, ensure gaussian noise, rather than uniform, is selected. This looks at the brightness values in your image and adds noise in sympathy with them, while uniform simply adds random speckles. Also ensure the ‘Monochromatic’ box is checked.
Less noise is more. If you’re viewing the whole image and add noise until you can see it, you run the risk of adding more than you need. Instead, zoom in to at least 50% and add enough noise that the sharpest edges are just slightly blunted. You’re aiming to soften your image ever so slightly and add a hint of texture, not obscure fine detail entirely.
Once you’re happy with the look, close the Live Add Noise window. You’ll see your image now has three filters. Double-click the Add Noise layer’s icon if you want to amend things.
When you’re finished, remember that File > Save As doesn’t let you change the file type. Instead, pick File > Export, which offers a panoply of formats.