Color, contrast and brightness Review


Color, Contrast and Brightness
Some of the most common forms of image editing include cropping (already mentioned on this page here) and changing brightness, contrast and color levels. Image editing opens up many possibilities for the digital photographer.

This is an example of some basic editing of a digital image. Before starting this type of editing on your computer, you will need to have the color on your monitor as accurate as possible.

In this example I will start with an image that was taken under cloudy conditions. The image has no shadows, which is great, the clouds however have created a dull looking image. Also the blue areas in the image are inconsistent with the blue in the other images taken on the day.

This is the original image, although the day was generally clear, there were clouds covering the sun at the time the shot was taken and the flash did not have the range to light up the image and therefore was not used.

I am using Adobe Photoshop 6 to edit this image, many digital cameras come with software that is capable of doing what I am going to do this image.

Firstly I will select the Brightness/ Contrast control.

Now I will increase the brightness and the contrast by a small amount, making sure not to brighten the image up to the point where it looks unnatural or grainy. It’s a good idea to look at the effect that the adjustment has on all parts of the image. Increasing the brightness will brighten up the dull areas and also the bright areas of the image, so care must be taken not to let the bright areas, like the clouds in this shot, become too bright and wash out detail.

Adjusting the levels of a digital image after it has been taken is a compromise. It is better to begin with a ‘perfect’ picture than to try to make an image perfect after it has been taken by using this type of software. In the real world of course, we rarely can or want to retake a bunch of images to get them perfect. Editing the image in this way, as long as it is done carefully, can yield an improvement in the image over the original.

Now that the image has been brightened up a little, the colors look a little dull, especially the sky and the sea, which seems to have a little more green in it than there should be. I am comparing this image to several other images I took on the same day to try to find the ideal colors. There are many ways to adjust the color levels in the image ranging from easy to complex. I am going to use a relatively easy option in Photoshop that should work with this image called Hue/Saturation.

I now select the color that I wish to change, in this case the sky blue and the tonal range of blue that will be effected by the changes I make. As I adjust the hue, the blue shifts to a deeper blue. Increasing the saturation gives the blue more prominence in the image. Only small adjustments are made to keep the image looking natural and to reduce any unwanted changes in other areas of the image that fall within the selected blue tonal range. Luckily with this image, the foreground area has almost no prominent blue within the tonal range I am adjusting, which makes adjusting the blue levels of the sky and sea a little easier.

To further illustrate the effects of changing the hue/saturation, I have taken it to the extreme in these images here,


The left image has had all of the blue in the image completely taken out, leaving a very gray looking sky and ocean. Any blue within the tonal range I have selected has been changed to gray. In the right image I have shifted the color of all hues within the image, giving the image an old style look. You can have lots of fun just using these basic color and contrast controls.

The final image has had one Brightness and Contrast adjustment and two Hue/Saturation adjustments within separate blue tonal ranges. Compared to the original image the final image shows an increased brightness and a deeper, more prominent blue, closer to the color of the other images that where taken on the same day. The image isn’t perfect, but is an improvement over the original.

Click here to compare to original image at the top of the page