HDR photography is done using 3 or more bracketed images. There are some instances though where taking three bracketed photos is not possible; for instance, action shots. In this tutorial I will show you what you can do if you only have one photo to work with.
When I was in the Alaska state fair this summer, I took this picture an the equestrian show.
I had my camera on sport mode and I like the timing of the shot. When I look at it though, it looks a bit bland and flat. Colors look desaturated and there is no real interesting contrast. This is where HDR comes in (For the record; I feel I should mention that what I am doing is not true HDR (since I only have a single non-raw image). I will be using tonemapping from an HDR program).
Once tonemapping has loaded, you are presented with many different options. I like using the default of the Mantiuk Operator with Contrast at 3.0, Saturation at 1.9 and Detail Factor at 2.5.
Change the drop down for your desired result size (probably the largest possible) then press apply. Save your image when it is done applying the tonemapping.
At this point, you may be satisfied with your image and have a nice tonemapped image. I find that it looks a bit too fake for my liking and so I like to open it up in the Gimp. The nice thing about using only a single image for tonemapping is that the original image overlaps perfectly.
Open both your original image and the newly tonemapped image in Gimp. For this picture I placed the original image above the tonemapped image and changed the layer mode to screen and opacity to 40 percent. For the finishing touches, I merged the two images then applied Colors>Auto>Color Enhance and Colors>Levels>Auto.