Quick Tip Thursdays - How to correct underexposed and overexposed images

Have you ever noticed when taking a picture some times, a part of an image appears too bright? So bright that its just a white glob ? Thats called a highlight or an overexposure. Then there are some parts of an image like shadows in pictures taken in the evenings / at dusk that have dark patches. Those are signs of the image being underexposed. A good image usually uniformly covers the entire range of the color spectrum. Most modern digital cameras nowadays have a very nifty tool called the histogram that shows you how well exposed the shot is. If you see a spike on the left of the histogram, you have an underexposure (or too much black). If you see the histogram spiking to the right, there's been overexposure and you have some highlights in the picture for which you will never be able to recover any detail.

Without getting into too much detail about histograms, here's a quick tip on how to make a dark image brighter without using the brightness control. Suppose you have the image below

This is SOOC with no editing other than resizing for the web and adding the copyright bar on top. The usual way one might think of making this brighter is to use the brightness option. However, sometimes, that tends to add noise to the image. Something that we don't like / want. A better way to do it is to create a duplicate layer of the "background" and change its blend mode to screen. Not sure what I'm talking about? Here's what I mean

If you feel the resulting picture is too bright, you can adjust the opacity of the copy layer to suit your needs. You can also use layer masks to brighten only select areas of your image. Here's the final result

If you want to darken an image thats too bright, follow the same process except use the option "multiply" for the blend mode. Now there you have it. Go play with your images and see what you can come up with. Feel free to post your images in the comments below !