Requiring recalibration A paint circulation system for a painting line, comprising: a supply channel, a return channel, a plurality of drop lines downstream of the supply channel and upstream of the return channel, the plurality of drop lines including a first drop Gustav Klimt oil paintings line and a second drop line, first control means located in the first drop line for controlling a first paint flow rate, the first control means including one or more lengths of first coiled tubing shaped to adjust the first flow rate according to a first flow controlling pressure differential. And wherein the first flow controlling pressure differential is the pressure differential across the first drop line between the supply channel and the return channel, second control means located in the second drop line for controlling Pablo Picasso oil paintings a second paint flow rate, the second control means including at least one second length of coiled tubing that is different than the first length of coiled tubing and shaped to adjust the second flow rate according to a second flow controlling pressure differential. And wherein the second flow controlling Van Gogh oil paintings pressure differential is the pressure differential across the second drop line between the supply channel and the return channel, wherein changes to viscosity in the paint do not result in changes to the system requiring recalibration between paint drop lines. Related articles: 1 Paint circulation line