I have several methods of converting a color image to black and white. This is an example of one. I used two programs on this image to get the final result I was looking for. LightZone (now defunct), and GIMP (GNU Image Manipulation Program). The Operating System I use is Debian GNU/Linux.
Note that this is not a detailed how-to by any means. In fact, it’s not a how-to at all, rather a how-I-did-it.
Original: Shot in camera RAW with a Nikon D700 (manual settings) and a 70-20mm f/2.8 lens. Ambient light measured with a Sekonic L-758DR hand held meter. The shot was over exposed 2/3 of a stop to ensure detail in the horse. What is produced is a slightly over exposed, flat image as below. Now on to the conversion and final edits.
The Conversion: Opening the RAW file in LightZone, the first order of business is to crop the image. Naturally I want to remove some from the left and top of the image, placing the subject in the left third as much as I can. This does two things. One, I get rid of the horse on the left. Two, by removing some from the top I draw attention to the barn door. A slight rotation to align the fence with the horizon. Finally I select a red filter for the black and white conversion. I want the grass darkened and red will do just that. Once the adjustments are made I save the image. Still, the image is somewhat flat, and has yet a few more things I need to add, as well as remove. Perfect. So I now save the image in tif format and exit LightZone.
Finishing touches: I finish out the image using the GIMP. Contrast, cloning, and decreasing depth of field are what’s needed.
For the contrast I simply select the auto contrast correction. However in doing so I lose some detail in the horse. To correct this I open the dodge tool. Selecting a soft brush and setting the dodge for the highlights I dodge all highlights on the horse. This gives a nice rich look with good detail.
I remove the straw on the horses neck, the car behind the fence on the left, and the light fixture just above the barn door with cloning and healing tools.
Isolating the subject by decreasing the depth of field is not as straight forward yet easy to do. I duplicate the layer, then blur it to the desired effect. Adding a layer mask I select the gradient tool and set it to radius. Placing the cursor on the horses nose I then drag it to the bottom of the tail. Now everything except the horse is thrown just a bit out of focus, mimicking even shallower depth of field. Any areas missed by the gradient I simply paint those in on the mask. I have now isolated the subject and am happy with the results below.