In this short tutorial, we're going to explain a couple of tiny steps to boosting the contrast in your photos. As an example, we'll use the following image:
This photo was taken on a Summers day in Suffolk, United Kingdom. What you see to the left, is the RAW image data taken directly from my camera. As you can see, in its present state, the image severely lacks any contrast.
What is contrast? Wikipedia I believe explains it well with, "the difference in visual properties that makes an object (or its representation in an image) distinguishable from other objects and the background." Here, our image lacks contrast, as there is very little difference between its highlights and shadows. This is what we aim to boost.
As stated in the introduction, there are often more ways than one to perform any one technique in Photoshop, and with contrast there is no exception. First we shall explore using curves to strengthen our photos. Begin by opening the curves dialog, go to Image - Adjustments - Curves... (picture left)
And here's what should appear (left). By default preset should be set to "None", Channel "RGB" and the curved line should be selected over the freeform pen (see below Channel).
Now what we have in this window is actually fairly simple. The square graph should be the only thing you're interested in. The 45 degree line running from bottom left to top right indicates the present state of our image. What we want to do is, using this line, manipulate our image.
Notice also the "Input" and "Output" labels on the x and y axis respectively. These provide great help in explaining how our Curves function works. Lets begin manipulating our image.
Click and hold somewhere in the top right corner of the graph. (creating a new node) Drag the graph up just a little, making note of the effect it has on your image. (should end up something like the image left)
Now to offer some explanation as to what's going on here, observe the image to the left once more. Image we have converted our image to black and white. Taking any lightish grey parts our image (in my case colours #cbcbcb and lighter), manipulate them to make them lighter. (e.g. #d7d7d7) Here we are changing our image's highlights.
Now lets repeat this step in reverse for our image's shadows. Again, click and hold somehwere in the bottom left corner of the graph. This time, drag up. (again, pay close attention to what this is doing to our image)
Again, noting the Input and Output levels we can note exactly what we're doing. We're taking parts of our image, that, when in black and white, would be darkish grey, and — you guessed it, making them darker.
Click OK and we're done. Take a look at our final image below, scroll up to our original to see the great results.
You may not be partial to this technique. If that's the case then you might find using Levels more to your taste. Again, this technique is extremely easy to do. To open the Levels window, in the File menu select Image - Adjustments - Curves... (shown left)
This brings up the Levels dialog, and all we need to do is taking the left-most node (black), and slide it right (in my example you should see I have moved the Black slider to 21). Now slide the right-most node (white) left. (in my example, to 236)
And that's it, two simple ways to add contrast to your images. Adding contrast to your photos is great when they seem dull and unlively, but it's not always the solution to image perfection. Avoid having to touch up your images by using a good quality camera, shooting in good light, and most importantly, taking the photo properly. Photoshop is a great fall-back, but if the picture's right, you needn't rely on it so much.
Thank you for viewing.