These days, most of the photos I put online or print out have had some form of post processing on them. I’ve nothing against unedited photographs, I just think that there are a few things you can do that make a difference, things that a film photographer would do in a darkroom as a matter of normal practice.
One of the most common adjustments I make to a photograph is the application of curves.
(OK, if you’re an experienced photographer or know all this already, switch off now…)
Curves adjustments allow you to tweak the tonal ranges in an image without changing the overall exposure. At its simplest level, you can brighten shadows (or make them darker) or do the same for the highlights. Getting more advanced, you can adjust individual channels (typically – red, green, blue) in an image to increase the contrast of specific colours. You can even use curves to correct white balance issues.
Typically, the tonal range of an image is represented in a curves dialog by a straight line running bottom left (dark) to top right (bright). When you adjust the tonal range, you manipulate that line, essentially adding a curve (can you see how they named it?)
Here’s some examples of pictures I’ve taken before and after curves have been applied. (Note, none of the pictures are great, but hopefully they show how curves can help).
In all the following examples, the original image is the part on the left.
By pulling the lower portion of the line down, dark tones within the image are intensified. The line becomes steeper as the contrast in the picture is increased, but the highlights in this (already blown out) image aren’t increased.
The original image here is a little dark, but simply increasing the exposure would have ruined the look of the dark grey suit. By pulling up the upper portion of the tonal line, the part dealing with the highlights, the shirt gets brighter as well as the face whilst the suit retains most of its original dark formal tones.
By using both the adjustments mentioned above, it’s possible to take a flat or lifeless photograph and breath a little contrast and life back into it. As the curve here shows, a little is often enough – remember the steeper the line the more contrast the picture will have.
Increasing a specific channel
Using the curves tool, it’s often possible to define a separate curve for each colour channel in the image. In this example, the highlights of the green channel have been stripped back, whilst the reds and blues have been made darker and more intense to differing degrees.
These are all pretty simple adjustments. It’s possible to have many points on the line and make lots of different adjustments all the way through the tonal range. But, typically a few minor modifications is all that’s needed.
Hopefully you can see the value of using curves to enhance an image. If your images are flat or dull, it’s easily the quickest way to bring some life into them.