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  Tone Mapping Plug-In Help
 
 
 
The Tone Mapping plug-in is a filter that reveals details in highlights and shadows in High Dynamic Range (HDR) images and enhances local contrast.
The resulting tone mapped image can then be converted into an 8-bit or 16-bit image that shows the whole dynamic range available in the original HDR image. Because the tonal range has been compressed while maintaining local contrast, the image is now ready for display on standard monitors and prints.
The Tone Mapping plug-in can also be applied to an image in 16 Bits/Channel mode converted from RAW.
 
 
 
Help Content
1.   Tone Mapping 32-bit HDR images
2.   Tone Mapping 16-bit images converted from RAW
3.   Preview and settings
 
 
 
Tone Mapping 32-bit HDR images
The Tone Mapping plug-in is intended for images that contain the whole tonal range information of a High Dynamic Range (HDR) scene. Such images are stored with a depth of 32 bits per color channel and are usually produced from differently exposed photographs of the scene (also known as "bracketed" images).
If you already have photographs of the same HDR scene taken under different exposure settings, you can directly merge them into a 32-bit HDR image in Photoshop CS2. For this, use the Merge to HDR function located under menu item Automate of the File menu.
The section Taking differently exposed images provides some tips for taking bracketed shots.
In any case, it is important to ensure that your HDR image is free of noise. For this, your bracketed shots should include at least one image that correctly exposes the deepest shadows of your scene. If you had to shoot at high ISO settings, it is recommended to apply a noise removal tool to your bracketed shots before merging them into an HDR image.
Once you have opened or created a 32-bit HDR image:
1. Go to Photoshop's Filter menu, locate the Photomatix item and click on Tone Mapping.
2. Adjust the tone mapping settings if necessary (see section Preview and settings for details).
3. Click on OK to apply the tone mapping to your image. This will compress its tonal range down to a range that standard monitors can correctly reproduce. However, Photoshop will still keep a 32-bit depth to store the image, even though it is not necessary anymore.
4. Go to Photoshop's Image menu, click on Mode and select either 8 Bits/Channel or 16 Bits/Channel. On the HDR Conversion panel, keep the default method Exposure and Gamma with Exposure 0 and Gamma 1.
Important note: When applying the Tone Mapping plug-in directly after "Merge to HDR", you may notice black artifacts on the tone mapped image. Most likely, the artifacts come from incorrect preview settings: Go to Photoshop's View menu, click on 32-bit Preview Options and set the Exposure to 0.
 
 
 
Tone Mapping 16-bit images converted from RAW
The Tone Mapping plug-in also works on images with a depth of 16 bits per color channel. However, you will only get good results if the level of noise in your 16-bit image is as minimal as possible.
To ensure a low noise level, we recommend exposing for the shadows when taking the RAW image, i.e. to overexpose your shot. Even though the histogram of your camera may indicate that your highlights will be lost, you should still be able to recover them during RAW conversion -- unless the dynamic range of your scene is too high, but then a single RAW will not be sufficient and you will have to bracket anyway.
When converting your overexposed RAW file in Photoshop, set an exposure of -1 or -2 depending on how much highlights you want to bring back.
Once you have converted the RAW into a 16-bit image:
1. Go to Photoshop's Filter menu, locate the Photomatix item and click on Tone Mapping.
2. Adjust the tone mapping settings if necessary (see section Preview and settings for details).
3. Click on OK to apply the tone mapping to your image. This will compress the tonal range from 16-bit to a lower range that standard monitors can correctly reproduce. You may still want though to keep a depth of 16 bits per color channel to ensure a high precision for further processing.
 
 
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