It's often agreed that logos should always work in black and white... am I right in thinking that doesn't mean greyscale, and literally just means black and white i.e. positive and negative space?
It would certainly make a logo more versatile, but then obviously doesn't give the designer as much room to be creative. I also see a lot of logos these days that wouldn't work in just black and white... such as those with gradients and those making use of blend modes:
Of course logos can have an alternate single colour version that can be used when necessary... but that just seems a little inconsistent to me.