I hope you don’t mind bringing this thread back on-topic, since I need more input for my own reassurance.
I think Andrew Rodney answered my question, although it’s quoted from another thread: “A working space is a container for holding you image data and it has a fixed gamut. You can shoot a gray card in RAW and encode that data into two working spaces of differing gamuts. It might fully fit within sRGB and it will of course fit in ProPhoto with a heck of a lot of additional gamut around this data. So looking at the scene gamut before even deciding what working space to use for encoding is useful. If you can fit this gray into sRGB, using ProPhoto buys you nothing.’
ProPhoto RGB has no advantages if the color gamut of your image fits in another smaller color space. Therefore I think it’s wise to check for OOG colors and adjust your working color space accordingly.
Put into practice:
No OOG colors in sRGB, then sRGB is the preferred working color space.
No OOG colors in Adobe RGB, but OOG colors in sRGB, use Adobe RGB.
No OOG colors in ProPhoto RGB, but OOG colors in Adobe RGB, use ProPhoto RGB.
Considerations:
- There are no disadvantages when using smaller color spaces (if there are no OOG colors), but is there an advantage? A wider gamut gives you a wider range of color, but it doesn't give you more colors. The size of the working space's gamut determines the spacing of all possible values of each channel. The same number of colors is simply stretched over a larger color range. This means using a smaller color space gives you finer control over the color.
- High-bit editing gives you 32768 levels per color channel, but your tools use 256 possible values. Maybe (banding) artifacts are reduced, but your color control while editing is not any better. …or is it? This brings me to …
- Does using ProPhoto RGB have any real disadvantages when you work with small gamut 48-bit images. For example, I remember something that perceptual rendering (to the printer profile) attempts to compress the gamut of the source space into the gamut of the target space. Does that mean there is also a change in saturation when the image's gamut fits easily into the target space and there are no OOG colors?
I hope some can give more insight in this matter. I lack the knowledge to fully understand all possible consequences, but I’m tempted to leave ProPhoto RGB as my standard working space and use the space that fits my image.
Thanks!
Hendrik