Soft-Edged Cel-Shading Tutorial Author - Man1c M0g (http://forums.biorust.com/member.php?u=1)

The creation of cel-shaded graphics is a lengthy laborious process usually carried out in Adobe Illustrator and/or Macromedia Flash by patient professionals.  If, however, you want to bypass all the hard work, and merely require a basic cel-shaded image for a quick illustration at a pre-defined resolution, then this technique may be far more useful to you then a fully-fledged vector graphic.  Unlike our hard-edged cel-shading tutorial, the results of this process have much softer edges and are more suited to illustrations in printed material.
 

Step 1: Open up a stock image in Photoshop of any size and/or format. The best results for this tutorial usually involve large images with areas of bright colours with excellent colour separation. This does not, of course, exclude more detailed darker images, but getting a pleasing result from an inferior source image may take a lot more work, and leave you disappointed. Note: This image was donated by the very kind fabemiko - you can find the original over here.

Step 2: Before you go any further, Layer > Duplicate Layer the background layer, hide the new top layer, and select the lower (original) layer in the layers palette.  Now run Blur > Smart Blur and in the dialog box that pops up, set quality to high and change the mode to edge only. To define the edges of the image, adjust the Radius and Threshold values until you have the ideal mix of desirable edge detail and unwanted static.  In my example to the left, I set the radius to 3, and the threshold to 15.  This will undoubtedly differ for your picture.  Once finished, press OK.

Step 3:  Invert your layer with Image > Adjustments > Invert and then clean up your lines by running Filter > Artistic > Cutout.  Again, you will have to play around a bit here to get the best mix of desirable detail and illustration simplicity.  In my example image I used the following settings: Number of levels: 7 Edge Simplicity: 4 Edge Fidelity: 2 When satisfied with the preview, press OK, un-hide your top (duplicated) layer in the layers palette, and make it the currently active layer.

Step 4: Now for the bit where we put it all together!   Select Filter > Blur > Gaussian Blur and enter a value that averages out most of the detail.  In my example I used 10px.  Press OK, and then go to Edit >  Fade Gaussian Blur, setting the opacity to 100% and the blending mode to Darken.  Press OK.  Set the LAYER blending mode to multiply... or play around a bit with other settings. Note:  If you need illustration images with sections of pure colour, try using Smart Blur with the mode set to Normal instead of the Gaussian Blur.

Step 5: And its really that simple!   You should now merge the layers together with Layers > Flatten Image and adjust the colours using Image > Adjustments > Brightness & Contrast to achieve a cleaner brighter feel with the underlying colours. Note:   If at this stage your image is exhibiting areas of overly bright or dark colour, you should ideally go back to steps 2 and 3 & reduce your defining lines as much as possible.  Simply altering the brightness of the image via Image > Adjustments > Brightness / Contrast will not remove the differences in overall contrast.