I designed the sign in Inkscape, made a litophane of it at http://3dp.rocks/lithophane/.

The size was adjusted in Cura (rescaled) to get the graphics to be three layers thick and to fit the print bed.

After slicing, in layer view, the layer where the graphics started printing was pinpointed and "stop at layer" was added in "post-processing gcode". The filament was switched and printing resumed.