Make a stencil graffiti effect
Use Affinity Photo’s Threshold adjustment to nail a Banksy-like look
Affinity Photo’s Threshold adjustment turns an image to pure black and white. The traditional approach is to use the adjustment’s slider to control the cutoff point. It works well, but it’s an all-or-nothing effect.
Because the Threshold adjustment is a live effect, you’re able to paint on the image underneath the stencil while looking through the adjustment. This means you can then also use the Dodge and Burn tools to brighten and darken the image selectively.
Converting the image to black and white is just the first step. Changing the Layer mode from Normal to Multiply will hide all the white, leaving just the black visible – and you’ll need to color this using the Channel Mixer.
You could just leave it there, but it won’t look truly realistic. To add that extra edge, use the Blend Options dialog to make the dark areas in the underlying wall show through.
You probably haven’t paid the Blend Options graph much attention, but it’s a powerful way of limiting the visibility of a layer, depending on the brightness of the layers beneath it. By changing the shape of the graph you can make the roughness of the wall show through the graffiti artwork, which really makes it look as if the graffiti has been painted onto the wall some time in the past, and is starting to look worn out.
It’s these little details that make all the difference between an okay pic and impressive artwork. (Note: if you’d prefer to create this effect in Photoshop, you can find it and other techniques at bit. ly/2minps).