Godfrey
somewhat colored
OK, now if I have perfected a digital file to exactly what I like how come I can't easily print a digital negative so I can make a contact print on real B&W paper?
Um, do you mean you've rendered a positive digital image to exactly what you like and you want to invert it so that you can print a digital negative and then contact print that onto silver-halide photosensitive paper?
That's a complicated transformation, John. To properly invert a fully rendered positive image to a negative for the chemical print process, you have to apply the inverse of a gamma correction to the positive image in order to accommodate the print paper's contrast gain and tonal response in whatever print development methodology you've chosen.
To do this requires that you carefully control two things: the printing process and then the positive-to-negative digital inversion process, and in that order.
First, establish a reliable and consistent print process that will render a step-gradient negative image to a satisfactory positive. Then, use that positive to create a positive digital image of the step-gradient that matches the positive print, then use a tonal curve adjustment (in LR or similar software) to invert the image and match the negative step gradient image. Then you have to test that the printing inks used to make the output negative on whatever transparency or paper base you want to use respond the same as your original negative in the contact printer, and adjust the curve until you match the results to high fidelity. Once you have that total tonal curve adjustment, save it as a preset or template so that you can apply it to any B&W positive image.
At that point, you can "easily" print a digital negative from any rendered B&W digital positive image that will contact print to a satisfactory and high-fidelity silver-halide B&W print.
I did this process in the late 1990s, and found the consistency of the output was variable because of the materials available then ... they lacked sufficient stability to be able to just apply a well formed positive to negative transformation reliably without constant tweaking. It was due to the dye-based nature of the printer inks at that time, and the variable quality of the papers/transparency printing media. I kept working at it until about 2005, when the modern generation of pigment ink printers started becoming available. And then the modern generation of high quality ink printer papers started to become available, and I no longer found any reason to do the silver-halide print ... what came out of my pigment inkjet printer as a positive proved to be just as high quality and just as archivally stable. So I abandoned the digital negative process at that point, and print direct to high quality paper with my inkjet printer now from finished digital image positives. 🙂
G