HDR Software Review

In this HDR Darkroom tutorial, you will learn how to create a fantastic High Dynamic Range (HDR) image with HDR Darkroom, using three photographs of the same scene taken under different exposures, and how to process the HDR image to its best effect with HDR Darkroom.

Step 1: Taking photos of a HDR scene with HDR Darkroom

In order to create the best HDR images, you need to take enough photos (at least 2) with different exposures to cover the dynamic range of the scene.

Most digital cameras on the market offer an Auto-Exposure Bracketing (AEB) function, which makes the HDR capture relatively easy. HDR Darkroom enables you to align images if the camera moved slightly between frames, but using a tripod is still recommended.

In Step 2, we will load the images into HDR Darkroom.

Step 2: Open HDR Darkroom

Enter the working area of HDR Darkroom by double-clicking on the application’s desktop icon or enter through the Start menu if the application has been installed. The working area of HDR Darkroom is as shown below.

Step 3: Generate the HDR image with HDR Darkroom

Click File , select Create HDR (or click the icon on the right hand side) and the merge dialog will appear as can be seen below. At this time you will specify the merge options.

Align option area:

Choose No Align , photos which have been added will automatically be merged into a 32-bit float point HDR radiance map (digital negative) without applying any alignment technology.

Choose Fast , photos which have been added will be aligned using translational alignment technology and then be merged into a 32-bit float point HDR radiance map (digital negative). This option can only compensate for translational movement that took place during the capture process, but the alignment speed is usually fast.

Choose Slow , photos which have been added will be aligned using a feature matching method and then be merged into a 32-bit float point HDR radiance map (digital negative). This option can compensate for both translational and rotational movement, and even distortions during the capture process. This option gives much more accurate result. However, this speed is relatively slower.

Exposure option area:

If the exposure value in EXIF data is available in the photos, you can choose the EXIF option, otherwise, you need to choose the Guess option. The default option is Guess option.

Tip: If you are not sure about the whether the EXIF data is available in the photos, we suggest that you choose the Guess option. Our Guess option uses an advanced algorithm to ensure that the exposure values can be estimated correctly.

Once the options are specified, select the Add Image button to add the image sets (You can choose 8-bit images like JPEG, BMP etc. or you can choose 16-bit images like camera raw), Click OK to continue.

After this HDR Darkroom will use the selected photos and merge these into a single 32-bit float point HDR radiance map (digital negative) based on the selected Alignment and Exposure options. In order to let users view the results, a simple global tone mapping engine (Fast Tone Balancer) using the default settings is applied to convert the 32-bit float point HDR radiance map to 8-bit integer values so as to give users a first impression in the working area of what the results are going to be after merging.

Step 4 Tone Mapping with HDR Darkroom, here is the magic:

In order to obtain high quality HDR image please use the Tone Mapping option.

Next, click Development , select Tone Mapping (or click the icon on the right hand side) and the tone mapping preview window will be displayed. In the window you have three Tone Mapping Engines to choose from to process images.

• Local Tone Balancer (LTB) : This is a patented Local Tone Mapping Engine, which is aimed at balancing tones in the photo and reveal detail in both shadow and highlights

  Strength: Adjusts the local contrast of the image
  Local lighting: Adjusts the local lighting level
  Brightness: Adjusts the brightness of the image
  Saturation: Adjusts the color saturation of the image

• Local Tone Enhancer (LTE) : This is a patented Local Tone Mapping Engine, which has the strong power of extracting details in the photos .

  Strength: Adjusts the local contrast of the image
  Brightness: Adjusts the brightness of the image
  Saturation: Adjusts the color saturation of the image
  Fill Light: Used to reduce the contrast of a scene and provide some illumination for the areas of the image that are in shadow

• Fast Tone Compressor (FTC) : This is a Global Tone Mapping engine. The following helps to explain the meaning of the different options:

  Strength: Adjusts the global contrast of the image
  Brightness: Adjusts the brightness of the image
  Saturation: Adjusts the color saturation of the image

Also, HDR Darkroom provides color balance and black/white clip functions in the post processing area.

Once you are satisfied with your settings, click OK . Next, the full size image will be processed and the results will be displayed in the working area. At this stage you can choose to save the image in a number of different formats.

Batch Processing with HDR Darkroom

If you have a large amount of photos to be processed, you can use our batch model. We have made large efforts in adapting the default parameter setting of each Tone Mapping Engine to process various image contents automatically and nicely. Thus, our batch processing feature can process large amount of images without your interaction and automatically deliver batches of well-processed images to you. To use batch model, Click Batch, select Batch process, the following window will be displayed for you. Then specify different options and click Run to start batch processing.

To use batch processing, you must have a fix number of photos for each group. For example, if you use 3 photos to combine to a HDR photo, there must be only 3 photos for each group. For example, you have two groups of photos, one group are A1.jpg, A2.jpg, A3.jpg. Another group are B1.jpg, B2.jpg, B3.jpg. You can put them into the same folder and “Select 3 image at a time” for batch processing. However, if another group are B1.jpg, B2.jpg, B3.jpg, B4.jpg. No matter you “Select 3 image at a time” or “Select 4 image at a time”, problem will occur.

– End of HDR Darkroom Tutorial, Thanks for Reading –