This is a very simple method of making digital negatives using Photoshop and a computer printer. There is nothing fancy about this method. It will only do the basic contact printing - nothing elaborate - but it has worked for me. I printed on tracing paper using this method. As long as the paper being used is compatible with the printer or printer ink, it should work. The reason I used tracing paper is because my printer will not recognize transparencies or I would use something like pictorico. There is also a great deal of information on digital negatives on the internet, especially YouTube.
Open an Image: File>Open
Size the image: Image>Image Size
Invert the Image: Image>Adjustments>Invert
The image is now a negative
Flip the image so it will print correctly with emulsion side down: Image>Image Rotation>Flip Canvas Horizontal
Print the Image: File>Print
When selecting the options in the print screen, make sure the check box for Emulsion Down and Negative are de-selected. This is because we already inverted the image and flipped it horizontally (mirror image).