If I may add to Walker’s reply, do not use Print-Tool’s negative preference features with PiezoDN - they will not behave as intended since they are made for use with standard methods of making digital negatives in which a negative image is sent to the printer. With PiezoDN the quad curve performs the inversion which is why a black border is necessary in order to get a clear (un-inked) margin on film.
If my memory is correct, the current version of Print-Tool was released shortly after beta-testing of the original release of PiezoDN began 2.5-3 years ago. When I upgraded to this version of P-T I tried the negative functions to see if any were of use with PiezoDN and found that they are not.
Here is a screenshot of how I setup P-T for a PiezoDN negative:
Note the 4 layers in the Image Files and Text Boxes area. Only the top 2, black background and image, are necessary to print a negative with a clear film edge and no mask. The text and 21-step strip are things I find useful. Also note that the Negative box (circled in red) is not checked. This means that the Negative Preferences function is not active. This is important.
If you want a black printed mask around the negative to print a clean masked edge (without having to use a separate mask of rubylith or some other UV opaque material) you would add a white rectangle of something like 1 inch larger in both dimensions than your image size between the black background mask and the image.
Both the black background and any white mask can also be added to the image file by increasing the canvas size with the appropriate color, but Walker 's solution to this of using a separate layer in P-T is very elegant and also allows for easily adjusting the layout.
I’d also like to point out that Walker’s recommendation of a 2 inch bottom margin (right margin if printing in horizontal orientation as in my example) extra cautious - there seems to be quite a bit of variation in this regard among printer models and even different units of the same model. It is partially due to a QTR limitation regarding printing close to leading and trailing edges - generally 1/2 to 1 inch of unprinted margin is required to avoid banding in this area. But the other part that is more significant for us is the paper-feed mechanism and whether or not we need to disable the star-wheels to avoid marks on the negative. For example, on my first 1430 with the star-wheels removed, I needed minimum leading and trailing margins of 1 inch and 2 inches respectively. On my second (current) 1430, I tested for star-wheel issues before doing anything else and found to my surprise that there were no marks. This allows me to print as close as 1/2 inch on the leading edge and 1 inch on the trailing edge. On my 3880, with star-wheels disabled I have found the practical limitations to be 1/2 inch leading and 1.5 inches trailing. I guess my point is that it is worthwhile to test this for your particular printer.