For example, here’s a picture I took in Dyche Hall, the natural history museum at the University of Kansas.

The main subject is the dinosaur bones (or casts of fossils if you want to be scientifically accurate) hanging from the ceiling. This shot gets a reasonably good exposure (maybe a bit over, but nothing I couldn’t fix in post-production) on the subject and part of its surroundings. I’m particularly fond of the weird shadows the bones make on the wall on the right side of the picture.

But what’s going on outside? Nothing, because it’s so blown out that even the came strips in the window are all but invisible. The exposure is so bad that the bright sunlight bleeding into the shot is fogging the edges of the window frame.

So I fiddled with the settings and came up with this. Now the window’s okay (a bit over, but again fixable). The rest of the shot might as well not be there. The ghostly traces of bones suggest a horror story in which a monster lurks in the shadows. That could be fun, but it isn’t really what I’m after here.

I originally shot these in my pre-HDR days (Photoshop could do at least some HDR merging as early as 2005, but I didn’t start playing with it until years later). When I tried to use Photoshop to mask the dark parts of this picture and paste the good parts onto the first photo ... well, it didn’t work.

For starters, the two pictures aren’t perfect matches (as one might expect from two photos taken from a hand-held camera). Look at the left edge of the window and you’ll see what I mean. That made it hard to paste the two together neatly.

And even when I got everything lined up, it still looked weird. The properly-lit window seemed out of place when surrounded by the light-fuzzed edges of the window frame.

What to do?

HDR to the rescue!

Photoshop’s “merge to HDR” feature combined the two photos into a single image with the best of both worlds. It did all the level adjustment, perspective warping and other fixes to make the good parts of both pictures fit into one even-looking image. I even got to keep the interesting bone shadows on the wall. I lost a little of the left edge in the process, but that seemed a small price to pay.

To be sure, this isn’t a 100% faithful reproduction of what I saw. I made it hard on the software by giving it only two not-very-well-matched images to work with. The result is a somewhat other-worldly version of light and color.