Post processing an image is a major part of modern day photographic workflow. There are a number of tools to work with the image but I am going to describe my workflow using Adobe PhotoShop CS4. I have been using Adobe Lightroom 2 for all my editing needs but there were occasions where I felt the need for better control over image manipulation. So I decided to upgrade to PS CS4.

Image above is a typical landscape scene I try to capture. For this particular scene the contrast was high, i.e., sky was much brighter compared to the foreground hills. So I used graduated ND filters to bring down the contrast that my camera could handle. In this case two filters were used, a three stop and a two stop, stacked together.

I start by first looking at the image as received from the camera and try to figure out broad areas that need "selective" editing:

• Foreground hills need more exposure
• Foreground hills on bottom left part are a bit underexposed compared to hills on bottom right
• Hills towards the center of the image as even more underexposed

So let's start working on these areas first.

In order to selectively work on different areas it is necessary to create the so-called "masks". Say for increasing exposure of the image a mask indicates whether a certain part of the image will be affected (indicated by white color), or not affected (indicated by black color).

There are many ways of creating masks and the easiest way is to just paint using a brush tool. However, there are more precise ways of obtaining a mask and one of the ways is to utilize "channels" pannel. Using "threshold" adjustment on blue channel I was able to separate areas of foreground hills against the sky. Copy blue channel and name it "Foreground Hills". Now we create mask by selecting either dark or bright pixels.

In the previous step we created a channel called "Foreground Hills". Now we can load this channel as a selection, i.e., we will be able to select (marching ants) the pixels of interest. In order to do this load the channel from "Select" menu. Now this selection can be made as an adjustment layer. The only additional thing I have done here is to blur the mask and remove some of the areas in the sky.

The image has a definite improvement over how it started. Now we can work on the lower right section of the image which seems to be bit overexposed. A mask can be designed in a similar way using "Threshold" adjustment over one of the channels. I used red channel this time and played with threshold level to highlight lower right area.

This is the mask obtained using "Threshold" adjustment over red channel. I painted over the sky area to deselect it and futher blurred the mask using a 50pixel gaussian blur.

The lower right part of the image is now more evenly lit compared to the rest of the hill. There is bit of red cast on the lower right part which I feel need to be removed. This can be done by reloading the mask and operating with "Color Balance" adjustment.

Now using color balance sliders red cast can be removed. Note that the mask used was same as that used in Exposure 2. The hill has better perceptual lighting now.

Go back to the previous image and you will notice sun flare at the center of the image. In order to remove the sun flare I created a small diffused circular mask and used color balance adjustment to reduce the red cast. Now the image is mostly done as far as local adjustments are considered.

Finally I move over to Lightroom and adjust the saturation, white balance and sharpening before exporting the image to be displayed on the web. BTW, can you spot a deer in this image at the lower left corner?