[John Sadowsky Participant Posts: 169]

Topical debate

on: November 11, 2019 at 1:32 pm

Adobe RGB (hereafter aRGB) was proposed in 1998 as a color space that would largely cover the gamut of CMYK printers of the day.  Personally, I think it has outlived its usefulness.  I wonder if others have thought about this.

1. While percentage of aRGB was used as a metric for wide-gamut monitors – monitor technology has moved on.  aRGB extends the sRGB gamut into the greens, but has the same red and blue primaries as sRGB.  Today, we DCI-P3 on everything from cell phones, computer monitors and TVs.  DCI-P3 also pushes its green primary beyond sRGB (although not as much as aRGB), but DCI-P3 also has a nearly monochromatic red primary.
2. Cameras offer sRGB or aRGB setting – but that only sets the space for in-camera JPEG production (not raw image data).  I see in-camera JPEG production as an important tool for event photographers or photo-journalists who need to deliver images to clients quickly.  Does aRGB help for that?  If you wanted a wide-gamut in-camera JPEG option, wouldn’t a DCI-P3 be a better choice?  Today, there is a good chance the client has DCI-P3 monitor, but not for aRGB.  (A minor issue is that DCI-P3 doesn’t specify a TRC which is a necessary compression step, but that could be easily dealt with.)
3. The original intent (I believe) for aRGB was to provide an electronic storage media for sending images to a print shop.  But you can do that with any wide gamut color space, including ProPhoto RGB.  The file storage color space gamut will never match the printer gamut.  You have to do color management (rendering intent – perceptual vs. relative).  You can render your image to your print shop gamut (assuming they provide the ICC profile), and then store the result to a ProPhoto JPEG.  That gives you full control of the rendering process.  (Or, you could just leave the rendering up to the print shop.)  The advantage of doing this with ProPhoto is that it has a wider gamut than aRGB.  Another issue is that ProPhoto uses the D50 white point – which is preferred for ICC color management.  aRGB uses D65 – preferred for monitor viewing – but adds another step in the rendering process (hence potential color distortions) when printing.  (Note:  I print on an Epson P600, so I am not an expert on workflows for external print shops.)

JSS

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