So often I see photos that show people almost totally lost in shadows. Maybe a group standing in front of the Eiffel Tower – beautiful detail in the landscape, but the faces of the people are totally unrecognizable because of the shadows falling across their faces. 
Especially in photos taken with on-camera flash, the folks in front are way overexposed and the ones in the back row lost in the dark. It need not be so, there is help my friends! Some times all it takes is to let Auto Correct in Photo Gallery or a small move of the Shadows slider over toward the right to set matters right. In Picasa “I’m feeling lucky” may do the trick or the Fill Light slider.
The dark areas of our photos hide a lot of detail that is often totally unrecognizable. Those details can be brought out. It may not result in award-winning photos, but it may make all the difference at a family gathering.
The photo above won’t let you bring out any detail in the figure, so don’t bother to try. It is a “doctored” photo, I made the figure, actually a flat sculpture, totally black.
I did make some experiments to see just how much information can be extracted from a painfully underexposed photo. I used a white cloth with a near-white plate and a white egg on that. The lighting was very soft, diffused window light so there would be hardly any shadows. My camera decided that the exposure at f/11 should be 1/15 of a second. Now we all know that cameras can’t tell an all white subject from a normal scene. You have seen photos of those white dogs romping in snow – they are just a dingy gray all over. So I over-exposed by 2 1/3 stops – used a shutter speed of 1/3 second. Here is my photo as seen in Photo Gallery.
Note the histogram chart on the right. It shows the relative number of pixels of each shade, from totally black on the left to totally white on the right. There are just a few pixels that are below the halfway mark on the chart. The most pixels are bunched up near the right, the white, end. The cloth is not completely white and you can make out some texture in it. But looking at the photo you would conclude that indeed I had used a white cloth, a white plate, and a white egg, and the photo fairly represents my subject.
The next photo here shows the same scene but photographed at 1/250 second – four stops under the camera selected exposure, 6 1/3 stops below the photo above.
Hopeless, wouldn’t you say? Take a look at the histogram. All the pixels are bunched up tightly on the black end. But note that they are just a tiny bit above the left end. There must be some data there.
Photo Gallery offers a number of sliders in the Adjust exposure panel. Those little doohickeys under the histogram are sliders too. They can be used to tell Photo Gallery to spread out the data. By sliding down the one on the white end you can tell Photo Gallery which pixel value to amplify up all the way to the white end, the rest will be proportionally lightened too. Lets see what happens when the “white” histogram slider is moved way left to just above where there is pixel data.
Look at the picture. Amazing, isn’t it? Not quite as white as it should be. So let’s use the Brightness slider to finish the job.
Well, what do you think? Yes, it is astonishing how much useful picture information can hide in shadows. I hope I have convinced you that you should take another look at your “uselessly underexposed” photos. As I said, maybe not gallery quality, but certainly very much worth doing.
For a bit more background on the histogram, see my post in Photography Notes & Tips Use the histogram to improve your photos.
.:.
© 2014 Ludwig Keck
