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The Nik Collection is free and compatible with Mac OS X 10.7 through 10.10; Windows Vista, 7, 8; and Adobe Photoshop through CC 2015. We have no plans to update the Collection or add new features over time.

HDR Efex Pro 2 Tour

Merge Dialog


The Merge dialog is displayed when first opening a series of images into HDR Efex Pro 2. You can also access the Merge dialog by clicking on the Merge Settings button found at the top of the History Browser.

1 Warning Dialog
For multi-shot series, a number of checks are performed in order to identify issues that would otherwise result in inferior image quality. If an issue arises, a warning icon is shown in this area as well as on thumbnail images. The issue will be explained in this area; however, if there are multiple issues for the loaded images, only the most problematic will be explained here. To determine all of the issues, hover over the warning signs located on the thumbnail images, and tooltips will appear explaining what is occurring.

2 Alignment Checkbox
Shooting HDR images without a tripod can introduce movement between each shot in the series. Without taking any steps to address this movement, the resulting image can have strange artifacts in which objects may appear twice or more in the image, or have strange edges around each object.

The alignment algorithms in HDR Efex Pro 2 work to align each image so that the resulting merged HDR image does not have any alignment artifacts. Check the Alignment checkbox to turn on the alignment algorithms and reduce any potential alignment artifacts.

After aligning the images, HDR Efex Pro 2 will automatically crop the image to remove areas with only partial image information. It is normal for an image that requires alignment to be slightly smaller than any one individual image from the series.

After checking the box, the image will be updated in the interface.

3 Ghost Reduction Checkbox
Ghost artifacts are unwanted image details that are created by objects moving between each exposure in the image series and are a tell-tale sign of an HDR image. When merged together, the moving objects may be semi-transparent or may be only partially formed.

To remove ghost artifacts, HDR Efex Pro 2 has a powerful ghost reduction algorithm that analyzes the images in the series and removes the movement. With the available tools, you can determine which position to show that moving object, based on the different images found in the image series. Check the Ghost Reduction checkbox to turn on the ghost reduction algorithms in HDR Efex Pro 2.

4 Ghost Reference Image
Once you’ve checked the checkbox for Ghost Reduction, a Ghost Reference Image selector will appear over one of the images in the Filmstrip at the top of the Merge dialog. The Ghost Reference Image will only become active after you have turned on Ghost Reduction. The image selected in Ghost Reference Image selector will act as the basis for the ghost reduction algorithm, with the goal of making all of the moving objects appear as they did within the reference image. The ghost reduction algorithms will try to make the objects that were moving in the series appear in the same position as in the Ghost Reference Image.

If you experience any unwanted artifacts, experiment with different Ghost Reference Images at different Strength settings. As a general rule, it is best to select middle exposures as your Ghost Reference Image, as they will have sufficient image detail to act as a foundation for the ghost reduction.

5 Strength
Use the Strength control to adjust the ghost reduction effect further. The default strength of 100% is recommended for most image series. If ghost artifacts are still present in your image, try selecting another image using the Ghost Reference selector by either clicking on the target image or by clicking and dragging the Ghost Reference selector and moving it onto the appropriate image.

After you have selected another image, review the result in the interface or using the Loupe tool (see a). Often, changing the reference image is all you need to remove any ghost artifacts.

By reducing the strength, you can blend the original image with the image created by the ghost reduction algorithm. Reducing the strength can be helpful in case you notice any unwanted image details created by the ghost reduction algorithm.

6 Chromatic Aberration
Checking this box enables the removal of chromatic aberrations from the image. Chromatic aberrations are most often visible as colorful fringes around objects in your images, especially around well defined high contrast edges.

7 Chromatic Aberration Sliders
The Red-Cyan and Blue-Yellow sliders enable you to remove any chromatic aberrations from the image series. In order to best see the chromatic aberrations, open the Loupe tool and ensure that the Chromatic Aberration option (see b) is selected at the top of the Loupe. Adjust the position of the Loupe until you can best review the chromatic aberrations in your image. Chromatic aberrations are easiest to see at the corners of the image, especially with high contrast edges, such as tree branches on top of a blue sky. Each slider will attempt to remove the most common types of chromatic aberrations: green or magenta chromatic aberrations, or blue or red chromatic aberrations. Move each slider until the color fringes are no longer visible.

8 Loupe Tool
To open the Loupe tool, click on the magnifying glass button. There are two display modes for the Loupe tool: Ghost Reduction and Chromatic Aberration. To move the Loupe tool, click and drag on the loupe to position it over different parts of your image. The Loupe tool can be closed by clicking on the magnifying glass button again.

a Ghost Reduction
In this view, the loupe will show the merged HDR version of your image with ghost reduction applied, enabling you to see the ghost reduction effect in a zoomed in state. This can help you determine if the ghost artifacts were properly removed.

b Chromatic Aberration
This view will show a non-HDR version of your image zoomed in to 100% in order to best display the chromatic aberrations in your image.

9 Preview Brightness slider
This slider affects the 32-bit preview only and can be used to adjust the preview image in order to properly see and remove all Ghost artifacts. Moving the slider to the right will brighten the preview, and moving the slider to the left will darken the preview. Moving the brightness slider in the Image Merge Dialog will not change the final merged image.

< Back: Image Selection Dialog Next: Interface Controls >


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