Create an HDR Image from One Photo
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AFFINITY PHOTO FOR WINDOWS
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HDR, OR HIGH DYNAMIC RANGE, photography was enormously popular a couple years ago, then became so ubiquitous that even your cell phone can do it today. The idea is that you shoot three—or sometimes more—photos. One of them is normally exposed, one is overexposed, and the third is underexposed. You do this on a tripod, so they’re identical, then blend them in software, so the mid-tones come from the properly exposed photo, the darks from the underexposed, and the brights from the overexposed one. This makes a higher contrast final image that doesn’t suffer from a lack of detail in dark or bright areas, as can be the case from a single image, thanks to the way the sensors in digital cameras are built.
One of the problems with HDR is that it’s easy to do badly, and end up with a garish mess. Supersaturated blue skies are common, and other colors can be portrayed equally unrealistically. Software comes to our rescue, however, and for once it’s not Photoshop. -IAN evenden
1 RAW DEAL
To do this, you’re going to need a camera that can shoot in Raw. These files are the unedited data from the camera’s sensor, often at a depth of 12 or 14 bits, and contain more tonal data than is expressed in JPEGs, which are usually 8-bit. Frame your image so it contains light and dark areas—these are what you want to bring out in the final blend. It’s still a good idea to use a tripod and either a cable release or self-timer, even if you’re not planning on taking multiple bracketed exposures, because the additional sharpness of fine detail the stable platform enables is always welcome. The beauty of doing it this way, especially with a seascape, is that everything is guaranteed to be in the same place in each image, because a wave or distant bison can move a long way in the time it takes to rattle off three separate shots.
2 DEVELOPING SKILLS
Import your Raw file into Adobe Lightroom—we’re using Lightroom Classic—or another Raw image workflow app. You could do the whole thing in Affinity Photo, beginning in the Develop Persona, if you wanted, but we’ve got a soft spot for Lightroom. Work on the image until you’re happy, then export it as a JPEG. In the Develop window, reduce the exposure to -1.5 stops, export a new file, then increase it to +1.5 stops, and export again [Image A]. These are the three files you will use to create the HDR image, just as though you’d shot three frames with differing exposure settings.
3 SET THE TONE
Open Affinity Photo. If you’ve not bought the app, there’s a 10-day free trial available. Hop up to the “File” menu and select “New HDR Merge.” A window appears in which you can choose the files that will make up your project. We’ve left “Automatically align images” and “Tone map HD image” checked, which they were by default, before hitting “OK.” Once it’s done merging, you’re taken to Affinity’s Tone Mapping Persona, and presented with a series of preset choices for a final look, with options such as high contrast black and white, and “Dramatic” [Image B]. On the right are a few sliders for controlling the tone mapping in the image, which is the way the newly expanded dynamic range in your 32-bit document is wrangled into something that can be displayed on a typical monitor, or saved as a JPEG. At the top-right is a useful before-and-after split view button, with a divider that can be swept back and forth across the image.
LET IT SLIDE
The sliders on the right are where you take control of the process. There aren’t many, but some are capable of making enormous differences to your final
image. Right at the top, you’ll find “Tone Compression,” which is at 100 percent by default, and controls how many out-of-range tones are brought within the range. Leaving it at 100 percent gives you a brighter image, with trips down the percentage scale resulting in an increasingly dull look. Below it is “Local Contrast,” which is one of our favorites, but must be handled carefully. We’ve pushed it all the way to 80 percent [Image C], and the difference is easily seen in the split view—there’s much more contrast everywhere, and the image seems sharper all over. It doesn’t look exactly natural, though, and there’s clearly been some processing going on, even if the sharp new look is rather eye-catching. However, we might be able to tone it down with the other options.
GO INTO DETAIL
Heading on down, we have “Exposure,” “Blackpoint,” and “Brightness,” all of which control the brightness of the image. Then “Contrast,” “Saturation,” and “Vibrance,” which control the colors. We don’t want to touch “Contrast,” for fear of what it might do to our already contrasty image, but if yours is lacking in that area, it’s often the first slider to reach for. Then there are “White Balance” (which was taken care of at the Raw development stage), “Shadows,” and “Highlights,” which can be useful if you’ve got too much of one in your image. “Detail Refinement” is like a sharpening tool for your image. By default, this is set at 50 percent for “Radius” and 30 percent for “Amount.” We slackened “Radius” off to 30 percent in the pursuit of a more natural-looking result. Right at the bottom is a curves adjustment you can play with, if that’s your thing.
When you think you’ve finished, hit the “Apply” button at the top-left, and you’re taken to Affinity’s main Photo Persona after a small amount of processing time. You can see from the histogram [Image D] that the tones are spread completely across the range. Your image will be kept in the 32-bit color space until you export it, or you can save it as Affinity’s native file format to keep the extra depth.
WHAT IS A HISTOGRAM?
A display of all the information in your image, running from dark on the left to light on the right, a histogram is a quick way to identify whether your image is well exposed. Peaks bunched up at either end signify an image with large dark or light portions, and those that vanish off the edge are clipped to pure white or black, with no detail discernible in them by even the keenest eye. Adjustments such as “Levels” or “Curves” can be seen working on the histogram, as their effect is to change the position of tones. Increase the brightness of an image dramatically, and you’ll see the peaks bunch up at the right-hand side. A well-exposed image has data in almost every part of the histogram, with a smooth curve peaking in the middle considered ideal.