The max and min settings are quite sensitive. I am working with nearly-flat objects, so the two settings are quite close. I’m not sure why they don’t default to the actual max and min depths of the object, and instead makes you scrub very slowly until you find the points where depth changes from white or black to grey. But I’ve managed it with a dozen objects, now.
The “cylinder all white” meant that the min depth was past the middle of the cylinder, so everything you could see was close than the minimum depth, and thus white which is the closest color, and when it’s all black that means that the max depth is closer than the front of the cylinder so everything is further away than max, and thus is black, which is the furthest color.
Yes, far from obvious.
I’m using Meshlab 2016.12 on a Mac running MacOS 10.12.6.