Hybrid RAW Conversion
Luminous Landscape’s latest article is a technical look by Jonathan Wienke at using linear and non-linear RAW file conversions to produe a black and white image.
“As I refined my B&W technique, I began using linear RAW conversion because it allows one to easily make use of 100% of the dynamic range captured by the sensor. Linear RAW conversion is difficult to use for color images because no tone curves are applied to the image data; there is no profiling or color adjustment done during the conversion process. In addition, images converted in linear mode tend to be extremely dark, and require fairly radical gamma adjustment to get the image to look “right”. But the slightly odd-looking color common to linearly converted RAW images is not an issue when the image is being converted to B&W. I discovered that if I normalized the color channels of a linear RAW conversion (basically “stretching” the values of each color channel so that they ranged from the minimum to the maximum values) and then applied a gamma adjustment of about 4 to 5, I would have a color image that, while frequently looking a bit odd in color, would always convert to a very nice B&W.”