Sugar lift etching is a long process by which cooked sugar (like caramel) is used as ink on a copper plate.
Once the caramel dries, it is coated with a "stopping" layer. Once dry, the copper plate is placed underwater for a day or two. The sugar melts, the "stopping" layer is lifted, and lines are revealed.
The plate is now ready to be immersed in the etching acid. Once the copper plate is etched with the sugar lines, aquatint may be introduced to create gray areas.
The plate is now ready for printing. An oil-based printing paint is used on the plate, in this case, I pushed a raw sienna into the lines, then rolled some blue over it.
The element of surprise in inherent to the printmaking process.