1 Select your subject
With your Background Layer active, use the Quick Selection Tool to select around the subject. Draw within the subject to select its edges; hold down the alt key and click on areas you want to deselect as you refine your selection – release the alt key to re-select. The tool should learn what to avoid, but it doesn’t need to be perfect.
2 Remove your subject
With the subject selected, go to Edit>Copy and add a new empty layer (Layer>New Layer) before clicking Edit>Paste to copy the subject on to a new layer. Deactivate this layer by clicking the eye icon next to it in the Layers palette and click back on the Background Layer before pressing the Delete key.
3 Fill in the background
In Photoshop CC, the Content Aware feature will fill in the deleted background as best it can but you’ll need to use the Clone Stamp Tool to remove any residue of the subject. Select the Clone Stamp Tool, set Opacity to 100% and an appropriate size with 0% Hardness before roughly removing any outlines.
4 Select your splatter
Activate your subject’s layer and add a Layer Mask. Click on the Brush Tool and access the Brush palette (Options bar or via Window>Brushes). Select a splatter-style brush and set the Foreground Color to Black. Set the brush Size using the slider and rotate the compass to tweak the brush’s angle.
5 Apply your splatter
Ensure the orientation of the brush matches the direction you want the splatter to be moving in so it looks like it’s trailing behind the subject. Click along the edge of the subject to reveal the background beneath; the best effect comes from changing the brush style, size and orientation between every click.
6 Add your trails
To finish, add a new layer to the top of the Layers palette and repeat step 5 changing the size, angle and style of the brush regularly. This time, however, use the Eyedropper Tool to sample a colour from your subject and click outside of the subject so matter appears to disintegrate away of them. Change colour frequently.