From Digital to Cyanotype

Alternative processes for photography are most often UV light sensitive only. Because UV enlargers do not exist, you need a negative the same size as the final print for contact printing. In the past this has mostly been done with either in camera original negatives (using large format view cameras to produce the negative) or enlarged negatives using copy film. Tillman Crane, an accomplished photographer and platinum printer, has an extensive description on how to produce an enlarged negative in a traditional darkroom.

The resurgence of interest in alternative photographic printing in relative terms just preceded the emergence of widespread digital photography. William Crawford's The Keepers of Light published in 1980 was a guidepost for many early re-practitioners of  these processes.

Photography exists primarily for the masses and for commercial use to communicate, influence and store memories. Insofar as widespread commercial use overlaps the needs of the artist, materials are available for the artist's use. As digital photography began replacing traditional photography across a broad spectrum of the photographic business (event and sport photography, photojournalism, consumer) sources of materials for traditional film-based photography - including material for making enlarged negatives for contact printing - began disappearing.

I think it is this ability to blend the old alternative processes with new digital methods for making negatives that will rapidly emerge as the standard approach to making traditional photographic prints. 

At the top of this article is a (transmission) scan of the digital negative I created to produce the cyanotype print below. Using Mark Nelson's Precision Digital Negative system. I calibrated the traditional cyanotype process using step tablets to determine an ink combination to produce a negative on Mitsubishi Ultra Premium Pictorico film on an Epson 3800 with full tonal range and densities calibrated to the process, chemistry, paper and light source. Digital negatives are created on transparent film using dye or pigment based inks. It is obvious that the negative is not black and white as is a silver negative. Exploiting the different UV blocking capabilities of the different colors of ink in a printer is key to producing high quality digital negatives.

The second image above shows the coated sheet of Arches Platine paper with the cyanotype emulsion before exposure. The digital negative is sandwiched ("emulsion" to emulsion) and placed in my built-in vacuum frame in my custom UV exposure unit from Edwards Engineered Products.

My exposure time is 3 minutes and 32 seconds, which is quite a short exposure for cyanotypes. As the image just above shows, cyanotype is a printing out process, which means the image is fully created during exposure. Traditional silver gelatin printing is a developing out process which shows no image whatsoever until the exposed print is subjected to chemical action by the developer. Some processes like palladium printing are partial printing out process where the developer completes the visible changes started during exposure. For the exposed cyanotype, the paper is cleared of unexposed emulsion by placing it inverted in a tray of water, ensuring there are no trapped air bubbles under the paper, and letting it stand for 8 - 10 minutes. The goal is to remove all of the yellow emulsion stain from the image. Depending on your paper, your wash time may be longer. Following clearing, a 30 second dip in a tray of water to which a splash of hydrogen peroxide solution has been added will bring the image to full intensity immediately. The step is unnecessary if one has patience as the image color will strengthen to the same end result in 24 hours or more. I let the print drip free holding it by a corner, and then lay it flat on a paper towel. I take a roll of blue shop paper towels and roll it over the print to remove any surface water remaining and then allow the print to dry. Alternately you can simply hang dry the print. The print may be flattened in a press for final mounting and presentation.

I have a lot more to cover about digital negatives and alternative processes!

The Epson 3800 Printer

I use the Epson 3800 printer to produce my digital negatives. There, I've said it.

So, one thing I continually bump into is there's not enough time in the day to do all the things I want to do with my photography. And I try to ask people who are working in similar areas for recommendations on equipment and technique.

I have Epson 4800 and 9800 printers, and they are fine printers indeed. I do many a digital color or black and white print with them and have been very pleased with the results. The problem I ran into with these two printers occurred when I started trying to produce digital negatives for palladium printing with high key images. A negative for a mostly white image consists of large swathes of solid ink lay down on Mitsubishi Ultra Premium Pictorico film. While studying the prints I noticed that there were uniform horizontal varying bands of light and dark (oddly the size of the print head seemingly) forming an undulating wave that was visible in the final print. I mentioned this to Mark Nelson and he replied he had seen this before and called the problem venetian blinds (putting a name to my pain). Not on all printers, and only in large, low contrast light areas of the resulting print (corresponding to areas of highest ink density in the negative). Interestingly Alain Briot mentioned that he had seen this density variation artifact in the shadow areas of some straight digital prints, but that the effect seemed transient.

This is not the same as a clogged head resulting in no ink from one nozzle and microbands appearing across the print. That requires a cleaning cycle. These are 1 - 1.5" bands varying dark to light and back again running parallel to print head travel. The effect is very subtle (but noticeable - someone else noticed it first in a print) similar to paper warped by moisture and wavy and showing shadows - except the paper is flat.

Mark mentioned in a moment of my deep despair that he had never seen this on an Epson 2200 (which I had just given to my friend Ken) - or an Epson 3800.

An Epson 3800 is a fine printer for generating digital negatives. I mentioned that already, I think. With a 17" wide carriage it can produce 16" x 20" negatives for large contact prints. One limitation of the Epson 3800 compared to the Epson 4800 is that there is no roll media support. I have to cut down the Ultra Pictorico roll material to size to feed into the printer. On the other hand, the Epson 3800 has a much smaller footprint that the Epson 4800 and can be considered a desktop printer (the Epson 4800 strains that definition). It is reasonably priced.

I use the Epson 3800 for straight digital prints also. It holds both Matte Black and Photo (Glossy) Black ink cartridges and will automatically switch between inks depending on whether you are printing glossy or matte surface paper. Ultra Pictorico is glossy. Some ink is wasted during flushing of the shared ink line so you don't want to switch inks say between each print but rather group your printing sessions if you go back and forth between media surface types.

The printer is a work horse and I'm very pleased with it. 

Another feature of the Epson 3800 is that it outputs 16 bit files rather than 8 bit files - with the right operating system and driver. While it is missing on a list of pro-imaging printers that support 16 bit operation, it is on another list and I can confirm that the MacOS X 10.5 driver has the option for 16 bit printing. Mark Nelson hopes that the support for 16 bit images will result in even smoother tonal transitions in digital negatives.

Someday maybe I'll figure out what the issue is with the 4800 and 9800 printers. I've already varied platen height, ink density, print quality (dpi), suction, orientation of the media (when cut into sheets), and colors used for the negative. For now I don't use these two printers for making digital negatives.

I have not tried to produce digital negatives on other printers besides Epson. I suspect that is in my future.