Project: HDR and Tone Mapping

Friday, October 14, 2011 7:19 PM By Stephen J Christophers

Above: Nikon D5100 with 18-55mm lens. This image was created by converting the file into three separate exposure values before exporting to Photomatix HDR software, for exposure fusion and tone mapping. Further processing was done using Photoshop.

I've saved a selection of the best High Dynamic Range (HDR) 'tone mapping' images at my Flickr favorites. They're about the best examples, with respects to processing skill, photographic subject and composition, that I've personally found in the genre. Most of the photographers represented there show a large body of professional work that's worth exploring a little further. To gain more insight into the process of HDR, in general terms. Furthermore, they represent the level at which I'm striving to achieve, with my current work. Although, my camera, a Nikon Coolpix is letting me down, with lesser image clarity, the quality needed to produce the sharpness and resolution most of these guys are working with, in RAW format; like the top of the range Nikon or Canon with professional lenses are able to produce. Nevertheless, it's still possible to create HDR with my current set-up - lets look at my process.

My Tone Mapping Process: My current production method, also-known-as, "Unsharp Masking": using a standard image editing package with .jpeg image format. This is a technique that doesn't require RAW, and one to which I add other filter processes: Hue & Saturation, Threshold, Contrast, Blur and Invert to gain results. These standard filters are found in most free or professional software packages, such as Photoshop or Elements. Personally, constrained to a lower quality .jpeg with my camera, I've nevertheless developed a work-flow process that produces results over 30-50 layers. Including 5-10 layer compressions, over all. This helps to gain a detailed, yet highly-dynamic end result by using the image as a template, to render one layer at a time.

It's a little like chemistry: you've got to believe in the photographs ability to produce results using this method. Key in on image details, and contrasts in colour and light, in the original image. It's also important to take into consideration the image composition in order for the process to show an extraordinary end results. As it takes about 20 layers and three+ layer compressions before you start to see areas of clear definition in tone and contrast forming in specific areas of your image - Unsharp Masking alone is not enough to produce professional results. In the end, using this process depends upon which areas of the original image show the potential for the process to give you the clearest results possible, like details and colour contrasts. So, it's important to be aware of how this might change your original composition depending on how your image takes to the process.

Yes, there's software that produces good quality results, relatively easily. I find that using Photmatix can help, nevertheless the resulting HDR image is usually layered into my project using a layer transparency of 50%, or less. In some of my images I use Photomatix to merge differing exposures values (E/V) and apply Tone Mapping. Although, my manual technique gives your image the edge over most of these processes - or in combination - with respects to each image supporting its own unique personality and subtle differences, while also producing a uniformly inherent quality.