The postprocessing effects below were done with Adobe Photoshop (7.0; they also work with CS upto CS5). The ideas can be applied to other paint programs though, such as Gimp or Paintshop Pro. Click on the photos to be taken to the tutorial page that explains the effect.
Interesting post-processing types
Here are some creative processes to touch up photographs. They are explained only shortly.
Touching up portrait photographs
I shoot models now and then in my home studio (for examples, see my Dutch portrait page on Kodakmomentje.com). Since often no make-up artist is present, models make themselves up. Photoshop helps the finish touch. Here is a list of typical procedures I follow to touch up a photograph. I don't always use all procedures; it helps save time if you can skip some, and one photograph needs a bit more than the other. The list is sort of ordered from first to last procedure.
A quicker way these days can be to use ProRetouch by Totally Rad! Software. The Actions in that package (it's not free btw) are very useful when quickly doing portrait touch-ups. You can always elect to do things manually, to avoid the cost of any 3rd party plugins, but I can recommend it.
I'll try and make tutorials for each step.
Older post-processing tutorials
These are some tutorials I made back in 2006.
External post-processing tutorials
I have found these internet locations during searches for nice post-processing effects. Hopefully you will find the quality as good as you expect:
(c) 2006-2011 Dolphinity B.V. / Ruud van Gaal