HDR and Exposure Blending

You can use HDR on portraits, too

We’ve already established on page 23 that the brightness/dynamic range of a digital sensor has its  limits, and that once contrast goes beyond these limits something has to give – either you hold detail  in the highlights and let the shadows ‘block up’ or you expose to record detail in the shadows and let the highlight ‘blow out’.

There is a solution: all you do is combine a series of images of a scene or subject shot at different  exposures to produce a composite image with increased brightness range. The first way to do this is  using a technique known as high dynamic range (HDR). HDR is considered by many to be a gimmicky special effect that produces unreal, unnatural images, so it tends to have a poor reputation among serious photographers. However, it doesn’t have to be an over-thetop effect, as it can produce some great results.

The ‘proper’ way to generate the images for an HDR merge is to shoot a series of frames at different exposures (see page 53). However, it’s also possible to create ‘pseudo’ HDR images by taking a single raw file and processing it several times in your raw processor, and then adjusting the exposure for each one so you have a sequence of bracketed images. I often use this process for travel portraits as it’s difficult to take a sequence of images of a person without there being movement between frames, even if it’s just the blinking of an eye. Using HDR on portraits emphasises detail in the subject’s face, revealing every wrinkle, pimple and strand of hair. The results could never be described as flattering, but they look amazing. 

However, to create HDR images you need suitable software. Recent versions of Adobe Photoshop have an HDR option (File>Auto>Merge to HDR). However, I have never found this to be particularly effective and instead prefer to use the third-party application Photomatix Pro (www.hdrsoft.com). The latest 4.1 version costs $99 (around £61) to download and licence, and is available for both Mac and Windows. There’s also a slimmed-down version called Photomatix Essentials 3.0 (formerly Photomatix Light) that costs just $39 (around £24) and is aimed at newcomers to HDR, plus a plug-in for Aperture priced $79 (around £49). Another option is Nik Software HDR Efex Pro. This costs $159.95 (around £140) and is available for Mac and Windows (www.niksoftware.com). 

If you Google HDR software, other options will come up, some of them free, but these two are the most sophisticated.

Here’s a step-by-step to creating an HDR image using Photomatix Pro

1 SELECT FILES
Launch Photomatix Pro and click on Load Bracketed Photos at the top of the Workflow Shortcuts box. Drag and drop the files you want to combine into the box that appears, or use the Browse option to find and select the relevant files. Click OK.

2 PREPROCESS IMAGES
A dialogue box appears titled Preprocessing Options and has various check boxes and sliders. I just leave this in its default state of Align Source Images, Reduce Noise, Reduce Chromatic Aberrations and so on, and then click Preprocess.

3 TONE MAPPING
It usually takes 30-60 seconds to combine the exposures. A tone-mapped image then appears along with sample images created using presets within Photomatix Pro.

4 CHOOSE YOUR PRESET
There is an Enhancer-B&W preset worth trying, although I find that it rarely gives a satisfactory result. In this image I found that the Enhancer-Painterly gave the best HDR effect.

5 FINE-TUNING
Having chosen the best preset, you can then fine-tune the effect using the sliders in the toolbox to the left of the preview image. Adjustments are quite subtle, but it’s definitely worth getting to know how these controls affect the image.

6 SAVE AND RENAME
Once the Tone Mapping has been applied to the image, save it as a 16-bit TIFF file, re-name it and then choose a location where it can be saved to. Now open the image in Photoshop.

7 CONVERT TO MONO
Convert the image to black & white. You can do this using any method you choose, although here I relied on Nik Software Silver Efex Pro, adding extra drama using the High Structure preset.

Tutorial 3:36 PM