Luminous Landscape Forum

Raw & Post Processing, Printing => Colour Management => Topic started by: NAwlins_Contrarian on March 01, 2018, 10:06:43 pm

Title: Color space and rendering intent for B&W photos?
Post by: NAwlins_Contrarian on March 01, 2018, 10:06:43 pm
I have been trying to improve my B&W prints. Toward that end, I have two question:

(1) Assuming I output my raw conversion, which is made B&W as part of the process, as a 16-bit TIFF, would it be better to use sRGB or Adobe RGB as the color space?* In other words, does Adobe RGB have a wider ranger of neutrals that it can describes, blacker blacks and/or whiter whites?

(2) If I then import that TIFF into Lightroom for printing, will it almost always be better to print with perceptual rendering intent, instead of relative colorimetric (which I usually prefer for color photos)? My sense is that relative colorimetric has crushed the shadows in some of my B&W photos, and in a couple of experiments, perceptual better preserved shadow detail. But maybe I'm missing some relevant considerations.

Thanks!

* I often use DxO PhotoLab with DxO FilmPack. DxO's internal working space, at least in the older Optics Pro, was Adobe RGB, so outputting to ProPhoto RGB seemed pointless. Also, since the TIFF will already be B&W, the only consideration is how well the color space represents the range of neutrals.
Title: Re: Color space and rendering intent for B&W photos?
Post by: Doug Gray on March 02, 2018, 12:20:42 am
I have been trying to improve my B&W prints. Toward that end, I have two question:

(1) Assuming I output my raw conversion, which is made B&W as part of the process, as a 16-bit TIFF, would it be better to use sRGB or Adobe RGB as the color space?* In other words, does Adobe RGB have a wider ranger of neutrals that it can describes, blacker blacks and/or whiter whites?
It doesn't make any difference at all.
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(2) If I then import that TIFF into Lightroom for printing, will it almost always be better to print with perceptual rendering intent, instead of relative colorimetric (which I usually prefer for color photos)? My sense is that relative colorimetric has crushed the shadows in some of my B&W photos, and in a couple of experiments, perceptual better preserved shadow detail. But maybe I'm missing some relevant considerations.
Your observations about Per v RelCol in Lightroom is expected. Lightroom automatically uses BPC which rescales black to the paper's DMax and lightens everything else in proportion. Per. adjusts the tone curve so the overall appearance appears similar even though the dynamic range of the paper is lower. It does this by slightly increasing contrast in the midrange. At least with X-Rite products and most others.

Photoshop offers optional BPC and RelCol w/o BPC is best if the images' deepest shadows do not go below the paper's black point. With Lightroom you have no option. BPC is always enabled and RelCol will always lighten the printed image. Normally, this works out best since colors below the paper's black point can be clipped and even shifted in color when the image contains these darker colors.
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Thanks!

* I often use DxO PhotoLab with DxO FilmPack. DxO's internal working space, at least in the older Optics Pro, was Adobe RGB, so outputting to ProPhoto RGB seemed pointless. Also, since the TIFF will already be B&W, the only consideration is how well the color space represents the range of neutrals.
Title: Re: Color space and rendering intent for B&W photos?
Post by: NAwlins_Contrarian on March 03, 2018, 08:58:21 pm
Doug, thanks for your answer. And I'd forgotten about black point compensation--another piece of the puzzle--thanks for reminding me.