To the left of the bit-depth buttons is a slider labeled Strength which ranges from 0 – 100%. This control adjusts the level of local contrast enhancement. Moving the slider left produces more “natural” tones, but results look flatter and do not emphasize fine details. Moving the slider right intensifies contrast, punching up detail and adding dramatic tone. However overdoing this creates an unnatural appearance.
Below 50%, I find the Strength control produces results comparable to the CS2 HDR Conversion Local Adaptation method. At higher settings, it produces enhanced contrast results that I have not been able to duplicate in CS2. Strength defaults to 80%, which I do often find to be too high. For some images, though, having that top range may give a dramatic visual that you want.
To the left of the Strength slider is the Luminosity slider. This control brightens the image if moved to the right, or darkens it if moved to the left. Consider it to be similar to the midtones slider found in the CS2 levels adjustment. The default value is 0, and the range is -10 to +10. I find that pushing the Strength slider higher often darkens the over-all tone, so I raise Luminosity a little to compensate.
Below Luminosity is the Color Saturation slider. Defaulted at 46%, this control ranges from 20% to 100%. I find the default slightly low for my taste, but rarely adjust it by more than a few points. You may know how easy it is to overdo saturation, especially if your intended final output is a print. Photographers new to digital processing sometimes dial in too much saturation to make an image “look good,” when the issue is poor midtone contrast, sub-par black and white points, etc. HDR processing is very much about dealing with over-all image tone, enhancing local contrast, and picking good black and white points. So having to fall back on big saturation boosts to punch up an image should not be required. However, the control is here if you need it.
Immediately below the histogram are two more sliders that control the white and black points. White Clip defaults to 0.25%, while Black Clip defaults to 0.00%. I often put the Black Clip slider up a notch or two. Unlike CS2, Photomatix appears to pre-process the HDR luminance range to filter it down to a smaller subset in which image detail exists. Therefore it should be unnecessary to make big adjustments to the clipping points. But if you need to fine tune the image, the controls are here.
Below the clipping controls is the Smoothing drop-down list, containing four entries: “High,” “Medium,” “Low” and “Very Low,” with the default being “Medium.” The higher the selection, the larger the regions over which the contrast enhancements are smoothed. Smoother results look more “natural.” This control is analogous to setting the Radius value in the CS2 HDR Conversion panel, with similar effect. I normally use “High” or “Medium,” as I find the other settings look too unnatural for landscape scenes.
As an aside, one key difference between CS2 and Photomatix in this adjustment is that Photomatix provides only four discrete settings instead of a range from 1 – 250 pixels. Four settings may not be quite sufficient (six or eight would give a little more control), but it is a good approach for the types of images I work on. I honestly do not agonize in CS2 whether the smoothing radius should be 80, 82 or 83. Having that level of fine grained control adds little or nothing to the creative process for me, as I am focused on qualitative results.
This same effect often causes photographers to struggle with editing points on curves in CS2. There is a lot of precise control possible, but correlating that control to the qualitative results you want can be a challenge. Having fine grained controls is not a bad thing. However, difficulty making an initial selection that “gets in the zone” can make the tool time consuming and frustrating to use. Initial information indicates that Adobe is making improvements in this area with its Lightroom software. Hopefully software vendors continue to improve – most photographers want to concentrate on making beautiful photographs, not twiddling bits.
Below Smoothing is the Microcontrast control. Microcontrast defaults to “High,” and has the additional choices of “Medium,” “Low” and “Very Low.” I normally leave the setting on “High”. Sometimes small detail needs to be less emphasized. The application help file gives examples such as noisy input images and stitched images containing stitching artifacts. In these cases the control can be set lower. MultimediaPhoto is currently working on enhancements to this control that will permit higher settings without emphasizing image noise as much.
Finally, underneath the Microcontrast control is a set of buttons for dealing with parameter sets. The Previous button will undo the current change, while Default resets everything. The Load and Save buttons permit saving and recalling settings. Saving settings creates a small file with the extension “.xmp.” A library of these files can be built up to create a series of default looks that can be customized for individual images. This is a little harder to do with saved settings in CS2 because the curve edits are much more image-specific.
Here is a final look at the tone mapping window with the parameters I have chosen for conversion:
The key changes from the default settings include:
- Strength of 70%
- Luminosity of 2
- Saturation of 55%
- Smoothing of High
When I am satisfied with the settings, I hit the OK button and Photomatix performs the real tone mapping. This takes less than 20 seconds on my machine. The final results will look somewhat different than the preview, but I find generally they are close enough to achieve the look I want without a lot of iterations back and forth.
When the conversion completes, the final image (a 16-bit TIFF in this case) is opened in the main Photomatix window.
At this point the image can be saved for finishing work back in CS2. Here is what the final generated image looks like using the above tone mapping settings:
There are some interesting things going on here, and to my eye this is a better starting point than was the result that came directly out of the CS2 HDR Conversion function. I particularly like the ice in this version. However, the image is not finished, so back to CS2 for the final touch-up work.
Photomatix Final Touch-Up
With the tone mapped HDR image saved as a 16-bit TIFF from Photomatix, it can be loaded into CS2 for the finishing touches. When I did this the first time to create the tone mapped image seen at the beginning of the article, I did minimal touch-up work in CS2. This time around, to have a more level playing field in comparing the results between CS2 and Photomatix, I touched up both versions using similar adjustments.
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