How to give your photos an interesting edge using a feathered selection and the Pixelate filter
Open up the image for this tutorial from your disc. In your Layers palette (Window>Layer) you’ll notice that it’s locked and can’t be edited. To unlock it, double-click on the layer and in the pop-up window enter a name and hit OK.
Click the Create a new layer button at the base of the palette. Hit D to set your Foreground and Background colours to black and white and then press Ctrl/Cmd+Backspace to fill the layer with white. Drag the white layer to the bottom of the layer stack.
Click on the main image’s layer and select the Rectangular Marquee tool. Before making a selection, head to the Options bar and enter 40px in the Feather field. Draw a rectangle from one corner of your image to the other, leaving a gap between it and the edges of your image.
With the selection active and the image’s layer chosen, apply a mask by clicking on the small icon (a circle inside a square) at the bottom of the Layers palette. This will show the effect of the feathering on the border, with the white layer showing through below.
At this point the layer mask will be highlighted. Go to the Filter menu at the top of Photoshop and find Color Halftone from inside Pixelate. In the Color Halftone menu, set Max. Radius to 40px. Default settings for Screen Angles should be C1: 108, C2: 162, C3: 90 and C4: 45. Hit OK to apply the filter.
The Halftone filter creates a border of different sized spots. If you need to reposition the border to better fit your image, click on the small chain icon between the mask and image thumbnails in the Layers palette. Use the Move tool (V) to drag the mask around.
If you’re not keen on the white background, select its layer (bottom of the layer stack) and choose the Paint Bucket tool (G). Click on the Foreground colour swatch and choose a colour. Click on your image to apply the fill to replace the white layer.
When it’s time to save, you can choose to flatten all the layers by going Layer>Flatten Image. Saving as a JPEG will create a smaller file size, but any transparent areas will turn into solid white and the mask will no longer be editable.