|If you have images (e.g. archived scans) in Ekta Space PS 5 and you wish to open up RGB values close to zero to improve deep shadow separation, this can be accomplished beautifully, to a significant degree, by assigning the Chrome Space 100 profile in place of the PS 5 profile using Image > Mode > Assign Profile in Photoshop 6 through CS, or Edit > Assign Profile in CS2 or later (not by converting from one profile to the other using Convert to Profile). See shadow detail comparison.
It so happens that the tone curve difference between these two profiles is such that values nearest zero are opened up the most, with a nice, progressive curve that can help out scans with insufficient shadow detail if the shadow values are near zero. The chroma variant sets for each profile match the tone curve of the master profile, so if you want to have your choice of shadows either staying as they came from the scanner or opened up as they get from assigning Chrome Space 100, and also to be able to vary the chroma at will, you need both complete sets. Alternatively, you can use either set alone and stick to using RGB curves to work with the shadow detail. If your images will be printed over their lifetime to printers which are well-behaved and fairly perceptually linear, conversions from members of the Chrome Space set to the printer profile will protect the images from posterization better than conversions from Ekta Space, assuming you are working with 24-bit files. If you are working with 48-bit files it is less likely to matter