4. Select the Color layer and click Filter > Blur > Smart Blur. When the dialog box appears, adjust the Radius and Threshold sliders to smooth out the inside areas while still retaining the sharp edge. Click OK. The resulting layer should be missing its original textures with a simplified, well-defined set of edges that will be enhanced.
5. Duplicate the Color layer. Name this new layer “Outline.” Make sure the Outline layer is above the Color layer. To remove the color from the image and create contrast, use the Channel Mixer. Select the Outline layer and click Image > Adjustment > Channel Mixer. When the dialog box appears, click on the Monochrome check box in the bottom left-hand corner. This will make the image appear to be black-and-white. Adjust the sliders to suit your specific image. You want a stark black-and-white image with easy separations.
6. To create the black outline, use the Find Edges filter. Click Filter > Stylize > Find Edges.
7. To combine the color image with the black-and-white image, change the Outline layer’s Blend mode. For different images, I’ve used Multiply, Darken Color, Hard and Soft Light. If the outline edges are weak or too thick, try adding a Brightness/Contrast Adjustment Layer (Layer > New Adjustment Layer > Brightness/Contrast). The final image should retain the color while using a black outline to define the edges. The results definitely aren’t your standard postcard-type image.