Tip: Bring Contrast To Low Contrast Images
By Sean Bagshaw
Here is a quick processing tip for creating beautiful high contrast images from low contrast photos. Often times very balanced and low dynamic range scenes create low contrast images. Sometimes low contrast creates a soft but visually stunning image, as is often seen in foggy conditions. However, low contrast images are often just flat, muddy and visually dull. Other than simply observing that an image has low contrast, low contrast images can be identified by their histogram. Contrast is created when there are both very dark and light tonal values existing together in an image. Images that don’t have any strong dark or light tonal values, with all the visual information concentrated in the mid tones, have low contrast. In a histogram you will see all of the tonal values compressed into the center of the graph and no tonal information reaching the ends of the graph where the dark and light tonal values are represented. A low contrast histogram will look something like this:
There are many ways to introduce contrast back into the scene, but I find that using an adjustment layer with the blending mode set to Soft Light is a very quick technique and often gives very surprising and pleasing results. Adding a Soft Light adjustment layer in Photoshop is a simple two step procedure.
1. Add a new Curves adjustment layer. There are several ways to do this, but using the drop down menus just go to Layer>New Adjustment Layer>Curves.
2. The default blending mode for the new layer is “Normal”. With the new Curves adjustment layer highlighted in the Layers palette use the drop down blending mode list to change the blending mode from “Normal” to “Soft Light”.
That’s it. You should immediately see a dramatic change in the overall contrast of the image. If the contrast is too much you can dial it back by using the opacity slider to decrease the opacity of the layer. If there isn’t enough contrast you can duplicate the adjustment layer to double the effect. If you want to selectively apply the contrast to localized areas of the image you can paint on the layer mask with a black brush set to the opacity you desire. You can also try using the Overlay blending mode as it has a similar but stronger effect. Because we applied the blending mode to a curves layer, you can also adjust the curve to customize or fine tune the effect.
These sample images show the original low contrast image (histogram above) and the same image with Soft Light blending adjustment layers applied. This particular image required two soft light blending adjustment layers to achieve the result you see.
If you don’t care how or why the adjustment works…go ahead and start putting it to use. For those who like to know how the adjustment works I’ll give a brief explanation. The soft light blending mode is designed to identify all the pixels in an image that have greater than 50% luminosity and brighten them while at the same time finding all the pixels in an image that have less than 50% luminosity and darken them. Since contrast is created by having a greater range between the darkest values and the lightest values in an image, when the Soft Light blending mode darkens all the darker tones and lightens all the lighter tones, by definition it is increasing the overall contrast of the scene.