Photoshop HDR

High Dynamic Range processing creates a higher range of luminosity than is possible using standard photographic or editing techniques. The object is to reproduce an image which simulates what the human eye perceives. The eye is constantly adjusting its iris to the fluctuating range of tones it experiences in the shifting light conditions of the seen environment. The brain further processes this information so that we perceive a wide range of light and dark. Non-HDR cameras capture shots with a very limited exposure range, resulting in much detail being lost in either the highlights and shadows, or both. However, we can adjust our images in Photoshop using a series of narrow range exposures taken of the same subject, thus simulating the dynamic range and clarity of HDR images.

Processing HDR images in Adobe Photoshop has become even easier with the introduction of the HDR adjustment feature in the CS5 version. For example, open a few images via Mini-Bridge. Mini-Bridge was first introduced in Photoshop's CS5 version and is basically a shortcut to the full Adobe Bridge program, which is a great tool for arranging and categorizing your images within your database. If you don't see Min-Bridge visible on your Photoshop interface, go to File and choose Browse in Bridge. Then go to File again and choose Browse in Min-Bridge. The panel will open at the bottom of your screen - you may prefer to move this to stack alongside your other panels on the right-hand side of the GUI.

High Dynamic Range (or HDR) refers to a technique whereby we can achieve maximum depth in the shadow areas of a photograph, as well as finer details in highlights like clouds. The mid tones are then redistributed between the new pure black and pure white settings, resulting in a sharper, more detailed and dynamic image.

To perform some HDR image processing select a few images in Mini-Bridge. These should be multiple F-stop bracketed exposures of the same image. This method allows us to capture various tonal ranges of the same shot, usually taken with the assistance of a camera tripod. After selecting the images right-click on one of them and choose Photoshop and Merge to HDR Pro, and hit OK. This combines the images as an HDR Composite image, aligns them and opens it up in the new HDR dialog box.

If Photoshop detects a difference in the images' exposure values the Manually Set EV dialog box will open. Here we would choose the correct parameters for Exposure Time, F-Stop, and ISO. Alternatively select EV and enter the value. In addition you can change the balance to under or over-exposed by adjusting the Set White Point slider to control the exposure rate. You can also choose to save as a 32 Bit per channel image. This will increase your file size dramatically however.

Also note the various Presets at the top of the dialog box, for example More Saturated. Note also features like Remove Ghost - this would be the case in wind-blown branches creating a ghosting effect in the final exposure.

Alternatively, if you didn't shoot for HDR, that is, you only have one photographic image go to the Image menu at the top of the screen, choose Adjustments and note the new additional of HDR Toning. This allows us to simulate the effects of High Dynamic Range without having the multiple exposures usually needed, resulting in a really sharp image.

As we can see, Adobe are continually updating their Photoshop editing features, making available to the general user what used to be the exclusive domain of the professional photographer.


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Tom Gillan has been training Photoshop to corporate clients in Sydney for seven years. Visit us at http://www.designworkshopsydney.com.au/adobe-photoshop-courses/ for more information.