The main focus of my work on alternative printing equipment is the design of a UV exposer unit to allow a digital image to be scanned onto the emulsion of a alternative photographic print. Instead of using a UV exposure box with inkjet printed contact negative.
With a digital negative, because of the limited saturation of ink on the film, the resulting ability to block UV light, combined with the non-linear response to light of the emulsion, results in a compramise between maximum saturation, mid tones and minimum saturation.
One of the The advantages of controling the intensity and duration of light at each pixel means that unexposed regions recieve zero light. The tonal range is theoretically unlimited, but practically limited by overall print speed. This also allows the non-linear emulsion response to be compensated in a repeatable way, where in comparison for digital negatives the printer ink is not designed with UV wavelengths in mind.
Comparison of 2400DPI inkjet negative print vs 110PPI image
The aim of this comparison is to show that the you can have much lower PPI than DPI for the equivalent amount of detail. And a proof of principle that the direct digital exposer should have good image reproduction capability.
Kalitype print captured by digital camera
Same image on LCD screen captured by same digital camera, at equivalent image size / zoom.
Minimum focus image of kalitype print from inkjet negative @ 9600 x 2400 dpi
Equivalent minimum focus image of LCD screen @ 110PPI (8bit B&W) – Moire vissible from pixels vs digital camera sensor to capture image, and not visable in person.