I have a logo which has been designed using RGB colours. Part of the logo is in grey and the colour use for this is a middle grey, R127, G127, B127.
Several online colour scheme generators convert this to C0, M0, Y0, K50. e.g. https://coolors.co/7f7f7f-7f7f7f-7f7f7f-7f7f7f-7f7f7f
This makes sense to me at it is 50% black ink.
Photoshop however converts to C50, M39, Y39, K21.
Photoshop is configured with:
RGB: sRGB IEC61966-2.1
CMYK: Coated FOGRA39 (ISO 12647-2:2004)
As far as I'm aware those are the defaults - I've not consciously changed them. I'm based in the UK.
What is the reasoning behind each conversion method, and which would be the best to use when sending a CMYK version of the logo to a commercial printer?