HDR Tone Mapping
Once the ghosts are removed, it’s time to output the 32-bit file into Photoshop CS5 and begin making edits. Click the OK button. Here again, the process of opening the file into Photoshop may take a minute or two. Once the image opens, choose Image > Adjustments > HDR Toning, and you will be greeted with a now familiar looking set of controls that you can move around your workspace, as seen in Figure 3.
Figure 3 The HDR Toning image adjustment in Photoshop CS5 allows you to map the tones of a 32-bit HDR exposure, to create a pleasing contrast. Note that currently, you cannot apply HDR Toning to a layered image or a Smart Object.
Rather than start with the Edge Glow settings, I usually work with Exposure, and then the Gamma and Highlights sliders to set the global brightness of the image, and recover any lost highlights, respectively. Here the overall scene was too dark at first (typically the case), so I boosted the Exposure from 0 to .48. This turned some clouds pure white, so I pulled the Highlights slider back to -55%, which returned the cloud highlights to an acceptable level but also flattened the contrast a bit. To counter this, I boosted the Gamma slightly to a value of 1.23. The results are seen in Figure 4.
Figure 4 The most important part of tone-mapping an image is to get the overall exposure or brightness correct, and to recover any lost highlights while maintaining global contrast.
If you feel that any of the shadow areas are too dark or too bright relative to the rest of the tones, you can brighten or darken them by moving the Shadow slider until they look the way you need them to. One final tone-mapping step before moving on to the color edits is to add perceived sharpness and detail by increasing the Detail slider value. Here the Shadows were brightened slightly up to a value of +15% ,and the Detail boosted to +97%, as seen in Figure 5. At this point, the image is starting to come together but the color and contrast are still too flat; we’ll handle these issues shortly.
Figure 5 Tweaking the shadow brightness and Detail slider can help improve contrast and texture in the image, respectively.
To give the image more “color punch,” I boosted the Vibrance to a value of +11%, which made the sky a bit more blue, and the Saturation to 48%, in order to restore the warm colors on the building and some of the green in the trees. Note that it is often necessary to perform additional color tweaks after your initial pass with HDR Toning, and that some experimentation between the two color sliders is often needed to strike the right balance. The color-tweaked image is seen in Figure 6.
Figure 6 The Vibrance and Saturation sliders work in tandem to help you recover lost color from the exposure merge process. Some experimentation is often needed to find the right combination.
At this point, you may not need to make any further adjustments, but I find it is often that case that a few tweaks to Edge Glow and the Curve function will put the finishing touches on the HDR process.