How to Edit an image for a stencil graffiti look
Choose your image
Choose an image with a strong visual identity. A dynamic pose works well, or you could choose a portrait. Don’t worry about whether the color matches the background, since you’ll be dispensing with the color anyway.
Dodge and Burn
Switch to the Dodge tool, and set your brush tip to 0% hardness. On the graffiti layer, paint over the dark areas to brighten them up. Use the Burn tool to paint over the bright areas to bring back more detail.
Open Blend Options
Select the graffiti in the Layers panel and click the gear icon at the top, next to the layer mode label, which will read Multiply. The app will display this dialog, showing the source layer on the left and the composition on the right.
Adjust Threshold
In the Adjustment panel, look for the Threshold adjustment. A panel will pop up showing a histogram of the tones in the underlying image, along with a slider. Leave the slider at its default position of 50%.
Change to Multiply
Once you’ve completed the Dodge and Burn process, you need to get rid of the white. At the top of the Layers panel, next to Opacity, you’ll see a pop-up menu named Normal. Change this to Multiply; the white disappears.
Reveal the grime
In the underlying composition’s graph (right), click and drag the top-left anchor point so it’s about a quarter of the way up from the bottom and in the center horizontally. This allows the dark grime of the wall to show through.
Move adjustment
When you choose the Threshold adjustment, it will be applied to all layers. You only want it to apply to the graffiti image, so drag it to the correct layer in the Layers panel to make sure it’s nested within that one specifically.
Add some color
Go to the Adjustment panel, and choose Channel Mixer. Choose the Red channel (for red graffiti) and drag the Red slider to increase the intensity, and the Alpha slider to brighten the black so the red becomes visible.
Boost the image
Revealing the grime has made the graffiti a little washed out. Click on the diagonal line to make a new anchor point, and drag it so it’s directly above the previous point. Drag this point to strengthen or weaken the graffiti.