Understanding the Adjustment Sliders in Photomatix Pro
Photomatix is at the core most people’s HDR processing but it comes with a bit of a learning curve. There are so many adjustment sliders available that wrapping your mind around them all can be somewhat intimidating. Adding to the confusion is their tendency to interact with each other in sometimes unpredictable ways.
Most of the time when I’m processing an image in Photomatix I will slowly move each slider to each of its extreme points just to see what effect it has until I find the best setting. I have read many posts by other photographers who also use this method but at some point you want to understand the intended effect of the sliders. Knowing what each one is supposed to do can make your processing experience faster and a little more pleasant.
Photomatix ships with several presets that can set you up with a good starting point but I think most people prefer the “Default” preset! This one sets everything back to the default settings so you can begin to apply your own feel to the image. It’s important to reset to the defaults each time you start Photomatix because it remembers the settings that were used the last time it was open.
Photomatix has two processing methods: Tone Mapping and Exposure Fusion. Details Enhancer gives you a wide range of controls and the most flexibility when processing. Since I have only ever used this method those are the adjustment sliders that I’ll be discussing in this article.
The Strength slider is the foundation that your Tone Mapped image will be built on. It sets the initial contrast of the image to help bring out detail. The higher value you assign to Strength the more detail you will see. For really gritty images, there’s nothing wrong with pumping it up to 100% but other subjects don’t need that much. For example, I typically don’t use more that 50% on landscape images because they begin to look too surreal. Too much strength can add noise to smooth areas of your image, blue skies will begin to look grey and grainy if too much strength is applied.
This one does exactly what it says, controls the global saturation of your image. You’ll find that you use saturation in different ways depending on the image you’re processing. Lowering the overall saturation in urbex images can help draw the viewer’s eye to the details of the image and enhance the feelings of age and abandonment. Increasing the saturation in landscapes can help the natural colors pop and create a vivid image. Of course, you do want to be careful not to apply too much saturation. Colors that are already close to blowing out will begin to take on a psychedelic appearance and no body wants that.
Think of the Luminosity slider as global fill lighting, it increases the brightness in the darker areas of an image. As with all of the adjustments, the amount you apply depends on the type of image you are processing and the what result you are looking to achieve. An important thing to keep in mind here is that setting the Luminosity too far to the left or right combined with a high Strength slider can produce halos in areas with high tonal contrast.
Adjusting this slider changes the amount of contrast in the details of your image. It also brings down the brightness in the overall image. As you may have guessed this is where the sliders begin to work off of each other. You can use Detail Contrast to add some shadow into your image and pull back any extra Luminosity that you’ve added. You may also have to bump up your Luminosity to counteract the effect of Detail Contrast.
The overuse, and misuse, of this slider can be blamed for many of the super-surreal and haloed artifacts that are found in so many HDR images. Lighting Adjustments should be used sparingly and with care. The effect of this slider is completely different on every image. Pay attention to you image as you move the slider, you’ll see that it actually applies light and shadow to different part of the image. It almost functions like a graduated neutral density filter.
There is a check box called Lighting Effects Mode below the Lighting Adjustments slider. When this is checked, five presets are made available: Normal, Normal+, Medium, Surreal and Surreal+. In previous versions, you had to use either the slider or the presets but with version 4.2 you can choose a preset then use the slider to adjust it’s effect. Personally, I prefer to work completely with the slider and don’t use the presets.
Sometimes the process of merging different exposures can create harsh artifacts in areas of an image where the lighting quickly moves from very bright to dark. A bright window or a sunburst are good examples. The portion of the image surrounding the highlight can be rendered with a ‘stair-stepped’ transition instead of a smooth fall off from light to dark. Smooth Highlights can help correct these areas and return that clean transition.
White and Black point adjustments can be made to increase or decrease the tonal range in an image. Use this slider with you histogram to keep the highlights and shadows from clipping.
Gamma applies to the mid-tones and adjusts the global brightness/darkness of an image. I usually don’t touch this one.
Temperature is pretty self-explanatory. Use it to vary the color temperature of your image from cool to warm. I rarely make this adjustment inside Photomatix but it can help to return color to a clear sky that has lost its tint during processing.
This is where you can begin to remove some of the noise that will inevitably show up in your image. Clear skies are the worst but a heavy dose of Micro-Smoothing will help smooth them out. Be careful though, this adjusts the fine details of the whole image and will smooth sharp, gritty details that you may want to keep. The zoom-loupe doesn’t always render the effects of this slider so you really just have to wing it most of the time.
If you need to change the saturation levels in the highlight or shadow areas of your image separately these are the sliders for you.
Sometimes the adjustments we make during the tone mapping process can add unwanted artifacts or gradients in the shadows of an image. The Shadow Smoothness slider can help smooth out these problem areas but reducing contrast in the shadows.
Sometimes you need or want to add a little more shadow or smoothing doesn’t give you the results you were want. Shadow Clipping literally clips the shadow areas in your image. Use this slider with care because while shadow adds dimension to an image, too much clipping will render large areas to completely black.
You will find that not every slider needs to be used with every image and with a little practice, understanding how the adjustment sliders function in Photomatix will become second nature. Also keep in mind that while you can get acceptable results straight out of Photomatix it is just the starting point for processing your HDR images and more post-processing is often required.
Note: HDR One readers get a 15% discount. Simply use the code StrangeLands when you purchase the product on HDRsoft.com