In this tutorial quick tutorial I will show you how to create two nice comic effects in Photoshop that you can use in your 3D renderings. In this example I am using a nice render right out of Zbrush with no additional modifications.

I am using Photoshop in spanish, so maybe some commands are not well named here, anyway you should not have problems finding them.

The shader I am using here is the excellent Zmat Pewter by Grant Warwick.
Check out the Zmats library at http://www.pixologic.com/zbrush/downloadcenter/library/
(It is the 25/64 in the Matcap Matte category).

Anyway, the most important thing is to use a shader with quite high specular zones
and if possible some kind of cavity. Here i have also added a soft pink tint to the base material.

Bring the image into Photoshop and go to Filters/Add Borders

The most important value here is the third one. Put it to 0.
The higher the value, the more shaded the image will turn.

Play around with the other values to get the desired effect.

That will turn into this:

Pretty nice uh?

For the next effect, we will need to go to Edit/Transition right after we apply the first filter.
If you do any other action after you apply the filter in photoshop that command will not be available.

Here you can play with the blending of the effects of the filter. Put it to Color Dodge and hit OK.

Final result.

After that, you can play a bit with the overall tone of the image to give it more mood. Of course after all of that you could paint and repaint all you want :)

You could also use layers to do the same, just remember to duplicate the base layer before
adding the filter.

The higher resolution your image is, the finer the details. Also, the more the detailed is the mesh the better the filter will get the details.
You could also try another blending modes like Linear Dodge to get a less shaded effect.

If you have any questions, feel free to contact me.