After further studying the behavior of the exposure and brightness sliders and discovering how strong upward exposure adjustments can cause serious color shift, I am modifying my workflow as shown below. Instead of relying mostly on exposure adjustment I am beginning to think that brightness adjustment is a more stable tool. On a photograph +2 exposure or +150 brightness produce almost identical results the latter being slightly more restrained. Ideally, this much adjustment should not be necessary, but in a pinch try the brightness firs. Now I understand better why Lightroom “Auto” tonal adjustment almost always uses the brightness slider.

I have been using Lightroom since its original public beta before version 1 was released. It has become an indispensable tool in my workflow like many other photographers. It offers a very good set of tools for photographers in a very usable interface. Those of you who go back that far may remember another product before Lightroom was even announced, Raw Shooter Essentials and Professional. The Essential was free and the Professional was worth every penny I paid for it. Adobe thought likewise and purchased the company and its technology along with it. Several tools in Lightroom, later in Photoshop are descendent of Raw Shooter series. The most notable ones that are visible outside are Recovery, Fill Light, Vibrance, and Clarity sliders. Along with these, I would not be a bit surprised if the entire “Basic” group is a descendent of RSE including brightness, blacks, and exposure. Interestingly, I have found the information on the “basic” group the most spotty and “soft” in presentation and explanation. Generally, explanations go like this “brightness is kind of exposure control but leaves the end points alone”, “it is a kinder and gentler exposure slider”, and so on. There are many discussions on variety of forums and you will read a variant of these explanations peppered on the Internet. Even Martin Evening in his quite encyclopedic volume on Lightroom does not provide a fully satisfying explanation of how the Exposure slider adjustment differs from the Brightness slider adjustment.

To better understand the behavior of these sliders, which seem to do very similar but not identical things, I decided to study their behavior on an artificial gray-scale ramp. In Photoshop, I created a 1200×1200 blank image and filled it from left to right with a gradient map going from black to white. To make reading values more consistent, I posterized the gradient fill with 16 steps. After importing the PSD file in to Lightroom, I took RGB readings from each strip and recorded them on each strip in Photoshop. The resulting file had the steps all identified as Lightroom saw the RGB values. Since they were all identical, I did not repeat the numbers for R, G, and B channels. [Read more...]