my workflow is as follows: .raw conversion, global adjustments and grayscale conversion all happen in Lightroom, then I open the .raw file in Photoshop (ctrl+E) for local adjustments and soft proofing (I print using ABW profile for my Epson 3880 created by Eric Chan). If I'm not mistaken the image that opens up in Photoshop using the above workflow is still an RGB image, not a grayscale one. So I was wondering: do I lose anything if I convert the image to a gray working space in Photoshop? The advantage would be to have a .tiff file much smaller (1/3 than the one I would have if I saved the image in the RGB working space). I would also like to know: is it better to convert to a 1.8 gray space or to a 2.2? Or it simply does not matter? And last question: since the image that opens in Photoshop from Lightroom is already in black and white, does it matter which RGB working space I am using (Pro photo vs Adobe RGB) ??