Are Sepia Images Better?
As I may have mentioned before, one feature of the LX1 that I like is the ability to simultaneously store both a RAW file and a full-sized JPEG image, complete with whatever imaging mode is currently active: particularly grayscale and/or sepia toning.
Exactly what a camera does to the image to produce a sepia-toned image can vary. If the image is converted to 8-bit gray scale and then the processor just replaces the gradient of white to black with a gradient from light brown to the same darkened brown, then... well, you haven't gained much. In fact you've compressed the number of gray tones.
But if the conversion were more duotone-like, following curves that mapped the grayscales across hue as well as brightness, then there's the potential that there might actually be a larger number of discreet color values in such a toned image than there would be in straight monochrome. The result: smoother gradients, and a file format that could pack more of the original RAW info into a compact JPG package.
Does the LX1 do this the "right" way, by converting the original 12-bit RAW signal to 12 or 16-bit grayscale and remapping those 12 or 16 bits diagonally across the colorspace before quantizing to 8-bit and building the JPG? Sadly, I don't think it does. But some camera might...and the idea, that this otherwise merely decorative camera mode could be the secret path to higher-quality digital B&W, is appealing.