How to Make a Color Image Look Like a Sketch in Photoshop?

1. Open a color image in Photoshop. To get the best sketch image, high contrast images are preferable. If it's needed, you can adjust the image's contrast (Image>Adjust>Brightness/Contrast).

* Optional: After you choose an image (but before you adjust the contrast) select that image by pressing (Ctrl + A) and then press (Ctrl + C) to copy that image. Open a new Photoshop window and paste that image in the new window by pressing (Ctrl + V). Save it as a copy. This is done to preserve the original image.

2. Desaturate the layer that contains the image. You can desaturate by clicking on Image>Adjust>Desaturate.

3. Duplicate the desaturated layer. On the layer palette, you can duplicate the layer by right clicking on the previous layer and selecting the option of duplicating that layer.

4. Note that there should now be at least two layers: two desaturated layers, and depending on which version of Photoshop you're using, you may have a blank background layer.

5. Select and invert the duplicate desaturated layer. You can invert an image by clicking on Image>Adjust>Invert.

6. Notice that now, with the inverted layer selected, change the blending mode to "color dodge." The image will turn all white with few black spots on it.

7. Set the Gaussian blur to this layer. You can do that by clicking on Filter>Blur>Gaussian Blur. Then you can set the radius in between 4.0-9.0. Choose the one that creates a nice sketch effect.

Tips

* If you can't see the layers box, go to Window>Show Layers.
* Don't forget to flatten layers before you save it. You can do it by clicking on Layer>Flatten Image.
* There is also a filter available on most versions of PhotoShop that allows you to do this automatically.