3-1 : Introduction to Exposure
In the previous levels, you were introduced to the Photoshop toolset and other concepts. This level will deal exclusively with working with photographic images. The first level of this online course showed you how to use the tools on the toolbar. Later in this level you will use them in more direct examples. There's a good chance that if you're reading this, you have a digital camera or deal with digital/scanned images in some way. I hope that this level will guide you towards getting the most out of your images.
For now, this tutorial will explain the basics of exposure in digital images. A poorly exposed photo can either be too bright (overexposed) or too dark (underexposed). In the days of film this was caused by either too much or too little light hitting the film. When this happened, corrections were made in the darkroom to fix the image so it would make a good print. In tutorial 1-10, we looked at dodging and burning. This allowed you to lighten or darken specific areas of the image. The next tutorial will show you how to correct the image's exposure as a whole. When you're done reading, check out the video at the bottom of the page.
There is no such thing as 'perfect' exposure. Image quality is in the eye of the beholder. Some people prefer darker, contrasty images, while others like lighter and brighter images. This is entirely subjective and you'll discover your personal preferences as work more with photography (if you haven't already). Some scenes are very hard to expose correctly. You might have a dark shadowy background area, but your subject's face is in bright light - the background and your subject's face cannot both be exposed correctly. In other words you can't have it all (well maybe you can, but that's for another tutorial). In other words, a single image will not always make a great exposure of the entire scene. Different monitors and printers will treat the image differently as well. The goal of the photographer is to make sure that the important parts of the scene are exposed the best they can be.
So now that you know that isn't easy to make a perfect exposure and that what you like isn't necessarily what others will, how do you know how to adjust an image? Let's look at some examples and you can see for yourself.
Below is an image that I took in the front yard. It's a typical landscape photo with some grass, buildings and sky. I took 5 different exposures: 2 overexposed, 2 underexposed and one correctly exposed (all according to my camera's meter).
If you look at the above image, you'll notice that in the left and right, you will see parts of the image that look well exposed. The far left is just a little too dark, while the far right looks washed out.
Here are links to the images so can see the complete photos - Under | Correct | Over. Look at each one carefully and compare the 3 images. Here is the 'correct' exposure again, but with a very minor adjustment to show what I consider a well exposed image.
The main thought when adjusting exposure is you want to have what you think is the best possible image. Sometimes, you will get the perfect exposure straight out of the camera. But many times you won't. Some people consider Photoshop a crutch that should not be used by 'real' photographers. That attitude is wrong, especially if you look at most famous photographer's work - a lot was done in the darkroom after the shot was taken. Ansel Adams is known as one of the greatest landscape photographers, but he was also a master in the darkroom. Make sure you get the best exposure you can so that retouching is left to a minimum. You can fix poorly exposed images, but they will never be as good as a correctly exposed image (that may have some minor adjustments).
Below are two images - the one on the left is horribly underexposed. You might not think that it can be salvaged, but click on it to see an adjusted version. The one on the right is better exposed, click on it to see the corrected version. Note that although the poorly exposed image still reveals the subject, it can not be adjusted to look as good as the correctly exposed image.
Click on the image above to see that
it can be salvaged
The image above is much better exposed than the one on the left - click on it to see how it looks.
Exposing properly in the camera is an entirely separate area of discussion and won't be covered here. I am currently working on a Photography course - check it out.
Remember that exposure is subjective, but if you are creating images for a series, they should be consistent. Try to develop an eye for over and underexposed images so that you know when corrections are needed. Start with the best exposure you have, so that the corrections are minimal (and also require less time). The next tutorial will show you different techniques for adjusting the exposure of an image. If you are serious about color and exposure, it helps to have a calibrated monitor .
Read about exposure on Wikipedia
Watch a video on how Ansel Adams worked in the darkroom.