Sometimes you will want to play with an image after the photograph is taken. This is where digital really comes into its own. By learning the tools at your disposal and the effects that can be used with them will lift your photographs to a whole new level.
Although we live in a digital age, it is silly to forget that optical effects can still produce interesting images. This tree was photographed by Geoff Watson and later the photo was framed behind glass. The apparent sunrise is actually an accidental flash reflection off the glass from when this photo of a photo was taken.

However, most of the time we cannot wait for happy accidents to occur. Tools such as Photoshop, Paint Shop Pro and others are nowadays key to a digital photographers arsenal.


The second image of a butterfly above was altered in the following ways. Firstly a radial gradient was added. The gradient went from black at the outside to white in the middle. By setting the blend mode to 'overlay' this made the butterfly much more the focus of the shot. However, the gradient also discoloured the butterfly, so I then cloned the original butterfly back in place. By placing the clone on a new layer set to 50% transparency it is easy to get a pixel perfect line up with the original butterfly underneath. The end result is only marginally different from the original, but playing with techniques such as these is a great way to spend rainy afternoons.
Vignetting is a similar special effect, but instead of altering the lightness,
we produce a gradient blur with only the center of the photograph in sharp
focus. Again, this makes your subject the center of the photograph the premier
point of interest. In years past a vignette was achieved by smearing a thin
coating of Vaseline around the edges of a lens filter. Vignetting can now
be done on the computer as an after effect.

To create a vignette you make a round selection with a wide feather, invert it and add a gaussian blur.

Eurrgghh, Nasty! But you get the idea.
Another great effect can be summed up as 'messing with channels.' You can split an image down into channels such as Red, Green and Blue or Hue, Saturation and Lightness, then adjust one channel before recombining. Take a look at the images below.

Here is a photo with no filters applied.

In the shot above, the red channel has had a seven pixel gaussian filter applied

In the shot above, the green channel has had a seven pixel gaussian filter applied

In the shot above, the blue channel has had a seven pixel gaussian filter applied

In the shot above, the hue channel has had a seven pixel gaussian filter applied

In the shot above, the saturation channel has had a seven pixel gaussian filter applied

In the shot above, the lightness channel has had a seven pixel gaussian filter applied

More combining makes things even stranger. This is a result of layering two of the above shots with the blend mode set to overlay.
Here is a high contrast effect which I like

The original image above is copied as a layer and made momochrome. This layer is copied and layered on top blend mode set to 'screen' at 50% opacity.
A copy of the original colour layer is placed on top with blend mode set to 'layer' and opacity at 80%. Lastly the layers are merged and 'noise' is added at 10% for a grainy look.

Another after effect which is commonly used to subtly brighten dull photos is to duplicate an image as a new layer with the blend mode set to overlay and the opacity set at around 40%. On top of this another duplicate of the original photo with blend mode set to soft light and opacity at around 15%. The resulting image is only marginally different from the original, but there is an added oomph that lifts the photo from dullness.

