Working space for Black and White

[Lucas]

Hi,
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) ??

Saluti,

Luca

[FranciscoDisilvestro]

Ciao Luca,

If you use the ABW mode with a profile then you can work with a gray working space in photoshop without loosing anything. Just keep it as a 16 bit grayscale.

RGB working space will not matter in this case, since it expects all values R=G=B.

I don't have a solid argument about the gamma, but I would suggest using a 2.2 value.

[Lucas]

Ciao Francisco,
thank you for your helpful reply.

[Ernst Dinkla]

Greyscale 16 bit, 2.2 Gamma or QTR's Gray Lab color space, there is a QTR RGB Lab color space for greyscale RGB files too.

If you do not use any of the Dotgain "spaces" of Photoshop ever, you better change the PS color management greyscale settings to one of the above choices.


met vriendelijke groeten, Ernst

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/

[bjanes]

Hi,
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) ??

A gamma of 2.2 is more perceptually uniform. See Bruce Lindbloom's companding calculator and his writeup to his BetaRGB working space.

[Lucas]

Thank you guys for your replies. bjanes: I tried to read the article on BetaRGB working space but that is a little bit over me   

So, according to your suggestions I would say that it seems optimal, from a B&W only perspective, to convert the RGB .raw file into grayscale in LR, then open it into PS using Adobe RGB (having a 2.2 gamma) in 16 bit, and then convert to Gray gamma 2.2 working space in PS (still 16 bit). I would then work on the photo, save it as a .tiff, and go back to LR for printing (using the ABW profiles) and exporting a .jpeg version to be posted on my website. It does not even look too complicated

[bjanes]

Thank you guys for your replies. bjanes: I tried to read the article on BetaRGB working space but that is a little bit over me   

So, according to your suggestions I would say that it seems optimal, from a B&W only perspective, to convert the RGB .raw file into grayscale in LR, then open it into PS using Adobe RGB (having a 2.2 gamma) in 16 bit, and then convert to Gray gamma 2.2 working space in PS (still 16 bit). I would then work on the photo, save it as a .tiff, and go back to LR for printing (using the ABW profiles) and exporting a .jpeg version to be posted on my website. It does not even look too complicated

If you are using Photoshop, you might try gray gamma  2.2