Convert HDR Raw Images to Black and White
If you convert your high dynamic range (HDR) images during Raw conversion, you must shoot your images and brackets in Raw and be prepared to convert them to black and white in your favorite Raw converter. Depending on the strength of the application you use, you can have more or less control over the process.
If you shoot using JPEGs only, these methods (as they pertain to Raw photos) are not applicable to you.
Here are a few examples of the options you might have:
Desaturation: This method certainly works, but you have no control over toning. Photoshop Elements (via Adobe Camera Raw) and certain Raw editors (such as the Sony Image Data Converter) offer this option. Sometimes, the only way to convert a photo to black and white is to completely desaturate it (in addition to altering its contrast, sharpness, and so forth).
Cameraesque presets: Nikon’s Capture NX 2 has handy presets that enable you to convert a color photo to black and white. Choose a camera preset with filter (green, red, and so in) from the Color Mode drop-down list in the Picture Control palette, as shown in this figure. You can also convert Raw photos using New Additional Adjustments in NX 2 (at the bottom of the Edit List panel).
Apple Aperture works the same way but also allows for a level of custom control.
Robust black-and-white toning: Applications such as Photoshop and Adobe Lightroom both contain extensive black-and-white conversion routines. You can see the Lightroom interface active in this figure. The Develop tab is being used to convert a Nikon Raw image to black and white.
If you want to convert your bracketed photos to black and white before processing them as HDR, apply the exact same settings to all images. This ensures a consistent conversion.