Many thanks to Matt Johnson for telling me about this amazing photoset on Flickr that details the process involved in printing the new Rush+ station maps for Washington, DC’s Metro system. Click through to see the whole set!

Even as an experienced graphic designer, I was amazed to see that the maps are screen printed — each colour on the map is printed one after the other, each using a separate screen with its own spot colour ink. With a map as complex as this, that means that there are a whopping twelve different colours to print! These being: river blue, park green, National Mall green, Blue Line, Orange Line, Yellow Line, Green Line, Red Line, Silver Line, District/County border grey, Beltway grey, and finally, black.

I would have thought with the advances in digital printing and stochastic (micro) screening, that these could be produced digitally in one step instead of twelve, but maybe these are special long-lasting UV inks that will withstand many years of use without fading — an important consideration for station maps! In any case, these photos are a fascinating behind-the-scenes look at a process that many people may not even think about.

Edit: A Metro representative has confirmed that there are THIRTEEN colours used in the printing: 4 greys (Silver Line, Beltway grey, county border grey, and icon grey), 3 greens (parks, Mall, Green Line), 2 Blues (river, Blue Line), Black, Red, Yellow and Orange.