A lot of people quote this line, but attribution in context appears to be sorely lacking...

I can help with background and dates.It was a quote developed during the time of using the typositor for phototypesetting headlines. Herb Lubalin, Aaron Burns and ITC were clients of ours who often required the careful and considered placement of one letter next to the other. We had to take into account the positive and negative space between letters. This was being done in a red light safe darkroom, exposing each letter one at a time and watching it develop under a "glass" which held liquid photo developer. Being a flirtatious man, my father came up with that quote during that period which was around 1985-1986. A couple of years later he became a consultant for a few companies including Adobe in their earliest years. That quote can be found in one of Adobe's first specimen books "Adobe Type Guide, Volume 1"