The first HDR Efex Pro article I wrote described the general workflow for merging a series of bracketed exposures, including basic pointers for initial raw edits and synchronization, the HDR Efex Pro interface, and the process of moving from a preset look to a more finished custom look. This article examines more closely the following HDR Efex Pro settings: Tone Compression, Global Adjustments, and Selective Adjustments.
The reason we’ll focus on these three components is that they have the most impact on the final look of your photograph. They allow the greatest degree of creative control and are the basis for all the presets that can be used.
Tone compression in HDR software is the process of taking all the raw data that was merged together from your bracketed shots, and combining it to create a “baseline exposure” that serves as the foundation for all of the remaining edits you make. Tone Compression also can help to create a balanced distribution across your Histogram, so that you have a range of very dark to very light tones to work with. Figure 1 below illustrates how the Histogram data shifts as you compress the data.
Figure 1 The adjustment makes the image brighter (original appearance left side of the preview), and a wider distribution of tones is visible in the second histogram.