Blocked shadows when dumbing down an image for the Web

[jsachs]

My error -- SMPTE 240M is gamma 2.2

[Charles2]

... and it appears that Changing color profile from a wide one to narrower sRGB typically blocks shadows on the histogram unless special measures are taken. You are right, J.S., that whether it results in a visible problem mostly depends on the variation in the sRGB monitor's brightness and contrast settings. (A real Keystone Kops thread here.)