The reason given is "a slab of black on the wall has a tendency to create a dark, depressing, uncomfortable and gloomy atmosphere", and they will be replaced "with a 'chalkboard' in some one of nine brighter colors"
Amusingly, the Collins English Dictionary (3rd edition) defined "chalkboard" as "a U.S. and Canadian word for blackboard." at https://archive.org/details/isbn_9780004332864/page/268/mode... . Archive.org says it's from 1981 but I can't find a date in the book.
And in "An Assembly Collection" by Joan Hasler, Headteacher at Dover Grammar School for Girls, (1986) is reading 128, titled "Green Blackboards"
The school is up-to-date.
Proudly, the principal tells of all the improvements.
The finest discovery, Lord, is the green blackboard.
The scientists have studied long, they have made experiments;
We know now that green is the ideal colour, that it doesn't tire the
eyes, that it is quieting and relaxing.
....
I also found mention of a "green blackboard" in Comedians, a 1975 play by Trevor Griffiths taking place in 1970s Manchester (see https://en.wikipedia.org/wiki/Comedians_(play) ): "his room, on the ground floor, is smallish, about a dozen chipped and fraying desks, two dozen chairs set out in rows facing the small dais on which stands the teacher’s desk, with green blackboard unwiped from the day’s last stand beyond." - https://archive.org/details/comedians0000grif_p3e8/page/6/mo... .
So it appears at some point there were at least green blackboards in the UK.
Great research. Obviously I was not being 100% literal when I said we don't have green blackboards (heh) in the UK. I'm sure somewhere someone has one, but I've literally never seen a single one so they must be exceedingly rare.
The reason given is "a slab of black on the wall has a tendency to create a dark, depressing, uncomfortable and gloomy atmosphere", and they will be replaced "with a 'chalkboard' in some one of nine brighter colors"
Amusingly, the Collins English Dictionary (3rd edition) defined "chalkboard" as "a U.S. and Canadian word for blackboard." at https://archive.org/details/isbn_9780004332864/page/268/mode... . Archive.org says it's from 1981 but I can't find a date in the book.
And in "An Assembly Collection" by Joan Hasler, Headteacher at Dover Grammar School for Girls, (1986) is reading 128, titled "Green Blackboards"
I also found mention of a "green blackboard" in Comedians, a 1975 play by Trevor Griffiths taking place in 1970s Manchester (see https://en.wikipedia.org/wiki/Comedians_(play) ): "his room, on the ground floor, is smallish, about a dozen chipped and fraying desks, two dozen chairs set out in rows facing the small dais on which stands the teacher’s desk, with green blackboard unwiped from the day’s last stand beyond." - https://archive.org/details/comedians0000grif_p3e8/page/6/mo... .So it appears at some point there were at least green blackboards in the UK.