Printing the Paper Copy

Confirm Correct Sign Choices

TLDR: Print the front facing layer as the positive and the back layer as the negative.

First, we need to know if we need positive or negative artwork. MG Chemicals' presensitized boards are positive resist - the part that is not exposed stays, such that the image exposing the board must be black where you WANT copper. Like all other chemical film, the lithograph process is negative - exposed areas turn dark. Therefore the printer output that will be used to make the film must be negative, such that the film print is positive. The circuit board program will with nearly 100% surety output a positive vector image - this will need to be imported to a high resolution B&W in e.g. photoshop and inverted.

The second set of choices relate to parity. First, we must remember that the art for the back of the board must be face up, and the art for the top side face down: The top and bottom must be mirrored relative to each other. Second, the film must be emulsion up (and the printed paper face down) to achieve a sharp transfer. Therefore the front face is mirrored twice (i.e. not mirrored) and the back is mirrored once (mirrored).

Create paper art

The UO copy center adjacent to the craft center in the basement of the EMU (adjacent to EMU falling skies) accepts high-resolution B&W images in png format. They have a delivery time of a few minutes and a cost of ten cents for a B&W page printed at high resolution onto fine surface photo paper.