HDR Darkroom: Working with Multiple Images

HDR Darkroom is a photo editing software with high dynamic range (HDR) image editing capabilities. The following tutorial describes how to work with multiple images with this sophisticated software.

Step 1: Taking Multiple Shots

The point is to take multiple shots of the same image with different exposure settings. For this, you can use the AEB (Auto Exposure Bracketing) function available in most digital cameras as this will provide an adequate coverage of the dynamic range of the image. Take at least 3 to 5 shots, and it is better to use a tripod.

Step 2: Loading and Merging Your Shots in HDR Darkroom

After you have initialized the software, you will be in the main work area. Here, you can click on the button on the right side of your screen or click on File, and then click on Create HDR. This will open a dialogue box for adding and merging your shots.

Step 3: Choosing the Options

In the dialogue box, under the Alignment column, you will see various options. These options are basically for correcting any errors which may have occurred during the shoot. Choosing the Slow Alignment option will give you the most accurate results, although it will be a slower process. It will correct the errors of distortion and rotational and translational movements, and after the alignment process will generate a merged digital negative of 32 bit float point. In the first option of No Alignment, there will be the same merged result but without any alignment taking place.

Under the Exposure options, you can choose EXIF if your image files have the exposure data in EXIF. Otherwise, choose the Guess option, which will estimate the exposures in your images. If you are not sure if EXIF data is available, it is better to choose the Guess option.  

After you are done with choosing the options, click on the Add button to include the photos you want to merge. The software supports RAW, BMP, JPEG and other 8 bit formats. Click on the OK button.

Step 4: Viewing the Outcome

After the process, HDR Darkroom will display the resultant digital negative or HDR radiance map in 8 bit values in the work area. This gives a fair idea of how the actual result in 32 bit float point will appear.

Step 5: Higher Quality HDR

In order to further enhance the HDR outcome, you can click on the Development button and choose Tone Mapping. This will open a panel on the right side of the work space with options and slider controls. The options are between three engines for tone mapping, namely Local Tone Balancer, Local Tone Enhancer and Fast Tone Compressor. These engines work on the contrast, lighting level, brightness and color saturation in the image. For example you can choose the Local Tone Balancer option if you want to extract more detail from the highlight and shadow areas in your image. After choosing the option and making the required adjustments, click on the OK button.

Step 6: Saving Your Work

Once the software has done the processing, it will again show the image in full size in the work area. If satisfied by the outcome, you can save it under various formats.