Next Meeting May 14th 6:30 to 8:30

This month's Artiest in Showcase is Bart Hickman

Bart is an electrical engineer and uses Photoshop as a hobby and learning tool for his children. He spends much of his free time with camera in hand taking prictues that he can enhance with Photoshop and take his skills to the next level. The following is a tutorial that he shared with us last month. Thanks Bart!

De - Grunge Tutorial
By Bart Hickman
2008 - April - 15

This technique is based on a tutorial at retouchpro.com called the "degrunge" technique by "byRO". In that tutorial, he used highpass filter whereas I'm using Apply Image - they are methematically identical.

In this tutorial, we'll start with portrate and apply the degrunge method to remove slight imperfection in the skin and leave the desirable textures intact. Here's the starting image. Image 1

Make a duplicate of the layer and apply Gaussian blur as shown. Choose just the right amount of blur to remove the skin texture we don't want without over-doing it without overly smootingin out contours like the cheeks and noise. Image 2

In this example, a blue radius of about 25 pixels seems about right. So now we have the original on the layer called "Background", and the bllurred on the layer called "Layer 1". With layer 1 active, choose apply image: and then set the Apply Image poramerts as shown. Image 3

The source layer should be "Background" and the blending mode will be subtract. Set the scale and offset to 1 and 128 respectively. This gives the opposite of the blur which is the highpass of the image. Except in this case it's the negative or inverse of the high pass. Image 4

Set the blend mode of Layer 1 to "Linear Light" and set the fill value to 50%. Adding the inverse of the highpass back at 50% fill back to the original image is equivalent to the original gaussian blur. Image 5

Now apply gaussian blur to the high-pass layer (Layer 1). This time use a smaller radius blur. Notice how the finer skin texture comes back. I've found that choosing this radius to be around 1/3rd of the first blur is about right for skin . What we have creted is a band-stop filter that is removing textures with radii between about 8 pixels and 25 pixels - this is the size of the undesired skin textures. Image 6

We don't want this filtering applied everywhere, just to the skin. So, add a blick mask to Layer 1 (alt-click the crete mask button) and paint white in the places where you want the degrunge effect. You can be prettly quick-n-sloppy here. Image 7

It's as simple as that. Continue with other processing.

Bart
bart-hickman@comcast.net

http://home.comcast.net/~zumbari/Tutorials/Degrunge/index.html