Dodge/Burn is not enough

Just this past week, Apple released a new version of Aperture, which now comes complete with a plugin that gives dodging and burning control. Today, Adobe releases into beta the next version of Adobe Lightroom, complete with (wait for it…) local dodging and burning.

And I’m here to tell you that while dodging and burning were the ‘de facto’ standard local controls in a wet darkroom, they’re not the right choice in the digital world.

In the wet darkroom, dodging and burning were strangely convoluted with the characteristic curve of the gelatin-silver paper. In the wet darkroom, the familiar S shaped curve of the characteristic curve (aka the H&D curve, or the Hurter-Driffield curve) had profound implications when we burned (increased exposure locally) or dodged (reduced exposure locally). If you burned down a shadow, you were forcing the tones in that region up onto the shoulder (highest density) portion of the curve, and so contrast would be reduced as you burned, and the more you burned, the lower the contrast got. Likewise, as you dodged the shadows, the tones would move onto the straighter portion of the curve, and contrast would increase as the tones in question moved off the shoulder.

Same thing in the highlights, but the other direction. As you dodged, things moved down onto the toe of the paper, and contrast fell. As you burned, things moved off the low contrast toe and onto the higher contrast middle portion, and contrast increased.

Sometimes those contrast changes worked to your advantage. Sometimes they didn’t, and you were forced to resort to other forms of prestidigitation to get the result you wanted. Things got easier with variable contrast paper, because you could dodge an area back during the main exposure, and then burn it in afterwards with a different contrast. In a very limited sense, using multiple contrast settings on a single print in the wet darkroom (something I did often) was equivalent to using a curve layer with a mask in Photoshop.

Every other technique (e.g. flashing, bleaching, or pouring hot developer on the print, or variable development) you might use in the wet darkroom means that you’ve started to employ tools that are much harder to control than dodging and burning. As a result, the vast majority of prints were made using the techniques of dodging and burning, and nothing else.

But it’s a mistake to think that as we move into the digital world, what we want is dodging and burning. We don’t, because dodging and burning have weak expressive power, and there’s an easy to use tool that can express every possible dodge and burn, plus a whole lot more.

That tool is called ‘curves’, and if we’re to be reduced to just one tool to do localized editing, we should run (not walk) away from dodging and burning, and instead rush to embrace curves with masks.

Let me demonstrate. When we burn an area down, we increase the ‘exposure’ and move all the affected tones down the tonal scale. This can be expressed with the following curve:

Likewise, a dodge moves all the tones UP the tonal scale, like this:

Once we have a way to express the action of burning and dodging, all we need is a way to restrict the action of the curve to a local region – and we do that by editing the mask for the curve layer.

That’s not the imporant point, because if that was all there was to it, we be better off with the simpler interface presented by the burn/dodge concept. The important point is that we can express a lot of things with curves that we can’t easily express using burning and dodging. In particular, we can limit the effect of burning and dodging not just spatial (by using a mask) but also tonally (by putting bends in the curve).

So, for instance, if we want to lighten the shadows, but leave the highlights and mid-tones alone, we might use a curve like this:

and if you want the mid-tones to increase in contrast, the shadows to get darker and lose contrast, and the highlights to get lighter and lose contrast (aka trade highlight and shadow contrast for mid-tone contrast), all without shifting the white point or black point, you use a curve like this:

The bottom line, here, is that by having curves and some way to control where on the image the curve is applied (and where it isn’t) you have the expressive power of burning and dodging, and then a whole lot more besides. There isn’t single tool I could deploy in my wet B&W darkroom that I can’t express simply and easily with curves and masks. Not a single one. Bleaching, flashing, variable contrast gradients, I can say it all with curves. And there are lots and lots of things I can express with curves and masks that were essentially impossible in the wet darkroom.

If you only get one tool, I’d suggest choosing the one that can do it all. It’s a shame that the developers of image editing software don’t see it this way.

[side note: Hurter and Driffield, the fellows who first graphically expressed the exposure/density relationship of photosensitive materials are two of my photographic heroes. Let me just close with a quote from them]

The photographer who combines scientific method with artistic skill is in the best possible position to do the good work

-Ferdinand Hurter and Vero Charles Driffield