Using special software to enhance HDR images after the tone-mapping process has become common practice today. There are a few software packages around the can be used to improve the appearance of the light and the details in the image. One of the more established and mature ones is Topaz Adjust which is offered by Topaz Labs for a reasonable price. While such a software can be used to improve images, it can just as well be applied to ruin them by overdoing the adjustments. In this recipe, I will show you how to use Topaz Adjust sensibly on your images to get the most out of them. You will learn which sliders to use and which ones you should better keep your fingers from.
Assumptions and Requirements
For this recipe, you are required to have a copy of Topaz Adjust (also simply called Adjust in the following for brevity) on your computer. Get a free trial copy if you need to. This trial copy is fully functional. This recipe is based on Topaz Adjust version 4 but may just as well work with versions before or after that. I am assuming that you have created your tone-mapped image and are ready to post-process it in Photoshop.
The very first thing we do in post-processing is to apply Topaz Adjust to the image. We apply it first because it can change the appearance of your image quite drastically. Thus, any subsequent processing steps should build on the new basic appearance. Otherwise, you may find yourself reverting or redoing some steps which would be a waste of time. You may argue that some noise reduction should be applied before Topaz Adjust. However, noise reduction has a tendency to blur your image, removing some of the details that we would like to bring out by using Topaz Adjust. Moreover, Topaz Adjust may bring in new noise which means that you need to apply noise reduction again after the processing, removing even more details and increasing the blur in your image. Thus, we apply Adjust first and then apply the right amount of noise reduction only once to deal with the increased noise.
NOTE: Another, more effective way of applying noise reduction is right before feeding your images into Photomatix. In this case, you may be getting away without any noise reduction in your post-processing work. Read more in my recipe on the “The Three Rules of Noise Reduction“.
Step 1: Open your image in Photoshop and start Topaz Adjust
After the installation, Topaz Adjust can be started from the Filters menu. This brings up the main window. I am not going to explain the entire functionality here. This is covered in detail in the Topaz Adjust Manual. I am going to restrict myself to how I use the program for achieving the results I want.
Step 2: Reset All
When you start Adjust for the first time, you will notice that there is a list of presets on the left side. It has become common practice to offer such presets in all kind of image editing software. I must say that I use this feature extremely rarely. And when I do, I learn time and time again that I like none of the presets that come with the program. The reason for this is that every image is different, and no two images look good under the same settings. Therefore, I do not start from some preset but from the neutral setting (the default setting that does not alter the original image at all). Since Adjust stores that last setting, I start by clicking the Reset All button.
This sets all sliders to their default (neutral) setting. Then, I gradually work my way towards the desired settings.
Step 3: Adjust the Exposure Settings
You should start by setting the Adaptive Exposure value. Increment it in steps of 0.10 to 0.15 and watch what Adjust makes of that. Of course, the optimal setting depends on your personal preferences and on the image (as with all the other settings). Personally, I find that value between 0.3 and 0.5 work best for most images. As I said, every image needs a little bit different treatment. I stop where the contrast in the image starts getting too high and things start looking artificial.
I have to admit that I touch all the other sliders in the Adaptive Exposure section only rarely. Sometimes, I change the Regions value to make the effect more global or more local. However, this tends to be more trial and error than goal-oriented work. I usually leave Contrast and Brightness at zero. They are not the same as the normal contrast and brightness adjustments in Photoshop. Usually, I find their effect unpleasant. Sometimes, it can help to protect Shadows and Highlights using the last two sliders. But usually, I stop well before that becomes necessary.
Step 4: Adjust the Details Settings
When you found a pleasing Adaptive Exposure value, it is time to work on the details. In order to decouple Details settings from the Adaptive Exposure setting, I always check the Process details independent of exposure check box. This makes the image a lot softer instantly, but increasing the Strength will cure that quickly. The best setting of the Strength slider heavily depends on the size of the image. For larger images (e.g. a vertorama), I usually need to go to values between 2.0 and 3.0 while normal images look good at settings between 1.2 and 1.8.
Apart from the Strength, I do not touch any slider in this section. Sorry, dear Topaz Team, but I did a lot of experiments with all the sliders, and I find that while Threshold and Radius do change the image, I have a hard time explaining their actual visual effect. For me, they do not make a lot of difference. So, I leave them alone. Boost is outright evil! If you change the Boost value the smaller details are strengthened. I found that this makes most images look bad and noisy. You better leave this slider where it is. Sharpening is better done with more sophisticated means in Photoshop.
Step 5: Adjust the Color Settings
The Color settings work nicely for some images while they are useless and detrimental on others. If you have a lot of white and grey in an image, increasing the Adaptive Saturation setting will introduce an ugly red, blue and green cast in these regions. You should use it with care. Increasing the Regions setting introduces even more color in regions where it does not belong, so I leave that at zero. All the other settings in this section have more powerful counterparts in Photoshop. So, no changes here either.
Step 6: Ignore the Noise Section and get a good Noise Reduction Software
Ok, this is not really a “step”. It is just to say that you should really have a sophisticated noise removal software. Otherwise, HDR and Topaz Adjust is not going to be much fun. If you have such a software, there is no need to use the Noise setting in Adjust. I recommend Topaz DeNoise.
Step 7: Go back to the Exposure Section if necessary
Sometimes you may want to do some fine-tuning when you are finished going through all the setting sections. Try to apply small changes to the settings until you are pleased.
The Process – Animated
The following figure (looping animation) shows a small animation of the whole process. Watch how I change the sliders and which effect they have on the image.
Tip 1: If you click and hold down the mouse button on the preview, you see the original image and can compare the before and after states.
Tip 2: If you make a change to one of the sliders, you can easily compare the effect in a before-and-after kind of fashion by using the Undo and Redo buttons in the upper right section of the Adjust window. This can help you judge the benefit of a setting.