4 bars - that's 25% - there are 16 bars?About 4 bars on my iMac 27". (2017 model year). Found I can soft-proof more accurately in LR.
Sounds about right. Yes, I thought it was low when I was advised by a pro printer to use that level, but it works for me. That's in normal grey (Yorkshire) ambient light, side-on to a window. The first time I tried it my print was spot-on, having struggled for years.4 bars - that's 25% - there are 16 bars?
edit with full brightness and then drop it to half, make any adjustments if needed before getting something printed