The Problem

The human eye can perceive a much greater dynamic range than does any camera available today. This means it is impossible to capture on a picture what our eyes are really seeing without losing details in bright and shadows areas. Furthermore, even if we could capture the whole dynamic range of a scene, there is no way to reproduce it on paper or screen, where we have limited Contrast available.

Without going deep into the science of vision perception, we can state that the contrast is what makes objects distinguishable from the background. A high contrast image or scene tend to bring more pleasure to observe. That’s why we like sunsets, sunrises, sunny days with blue sky rather than cloudy and gray-like scenes.

Contrast adjustment on a picture is a very broad subject and we won’t get into details here but just recall that increasing contrast usually means losing information displayed. Details in shadows tend to disappear on a ‘sea of black’ and bright areas tend to become white constant. So how to make images pop to the eyes while keeping as much details as possible?

One Solution

I will present here a technic I use to improve image contrast and make it instantly pop. Here I use Photoshop CS5, but any advanced image processor will have the needed tolls. Here’s the example image. A very common animal at Ein Gedi National Park in Israel. The left side is in its original form, as it got out from the raw converter while the right side of the picture has the final result.

The difference is noticeable. The right side lost the gray aspect and looks much more natural.

So how to do it?

The most straightforward solution would be going to contrast adjustment and push it up. Even if recent versions of Photoshop have a quite advanced algorithm to increase contrast and preserve details (try using it with “Use Legacy” selected to see the difference), it will result on loss of details in shadows and color burn.

Another technic would be apply a S-curve to the image, but it may result on lack of tonal detail in shadows and highlights also. So let’s try something else.

Local Contrast Enhancement

First of all, we want to work only on light intensity information, we do not want to mess with color, so we’ll convert our image from RBG mode to Lab Color Mode.

Now we select only the Lightness channel to work with.

Now we’ll apply an Unsharp Mask Filter, but unlike the common use, we’ll a large Radius value and a low percentage on Amount property. By doing this we’ll ensure a Local Contrast Enhancement at border areas, while keeping details on the rest of the image. You can play with properties values and see different results.

Here we are done. Activate back the other channels and see the final result.

I like this technic very much because it can easily make images pop while giving them a natural look. Moreover, it can be applied on 90% of the pictures I take.

Have fun,

Israel Lot.