Thanks Tho mas and Czornvi. I’m now a lot clearer about this.
So to summarise…… the RGB TRC has no effect on the monitors gamma and it dose not change the appearance or numbers of a greyscale image when it is opened, only when it is edited will the K values not behave as expected (ie in a linerised manner), if the dot gain profile does not match the working space RGB TRC - but then hey, what you see is what you get.
Following on from this Photoshop comes with three gray space profiles, sGray, Gamma 1.8 and Gamma 2.2 It would seem that these are actually the inverse curves, net result use sGrey with sRGB = linerised gray, Gamma1.8 with any RGB workspace with a TRC of 1.8 = linerized gray, and the same for the 2.2 gamma.
Tho mas I am definitely leaning towards your way of thinking with your suggestion of using an RGB space with L* TRC, eg eciRGBv2, if for no other reason than as you say there will be less errors in the numbers when converting profiles as the PCS uses L*a*b*. This of course now leads to another question.
Does anyone know where I can get a gray space profile with an L* curve (or more correctly if my assumptions are correct an inverse L* curve)? If not does anyone know the correct numbers to enter in the custom gray space gamma setup in Photoshop?
Also whilst on this whole gamma / TRC subject can anyone explain what effect the check box next to ‘Blend RGB Colors Using Gamma:’ (the default is set to 1.00) in the Photoshop colour settings has, and how does it work?
Thanks All for your posts.