I’ll always remember my first experiences in the darkroom, watching my prints come up, feeling like something magical was afoot. In recent years, I’ve frequently wished that there was an effective way to use my digital images in the darkroom, and make prints on fiber-based paper that has that special silver-based depth and luminosity.
Hewlett Packard Company has developed updated technology* that makes it possible to create a “digital negative” using a digital file or film scan. That digital negative can be used in a traditional darkroom to make prints of any reasonable size. HP calls this the Large Format Digital Photo Negative Solution. In this article, I’ll review the process in detail, including some of the methods used in the darkroom-printing phase.
The process consists of six steps:
1. Creating a base digital file via camera capture or film scan.
2. Performing normal editing of the image through Photoshop or other application.
3. Adjust image file for correct printing density.
4. Flip and invert file.
5. Print to HP Designjet Z3200 printer using the Photo Negative pre-set for the printer driver.
6. Make a contact-style darkroom print, using your preferred chemistry.
*Printing large format photo negatives with inkjet ink is an old concept. There are a number of books and methods that helped pioneer this. The goal in creating this solution was to make the process of printing large format photo negatives easier, and to achieve maximum quality using the HP Designjet Z3200 printer.
Creating a Base File
Image quality is, as always, a key driver in final print appearance. Obviously, a high-quality DSLR will (all else being equal) yield a better digital file and final print. Similarly, a high-resolution drum film scan will give better results than a scan made on a low-end tabletop flatbed scanner.
At the end of the day you’ll want a digital file that would also provide excellent quality as an inkjet print−a print the same size as the negative you plan to make. So, if you want a 16×20 negative, ideally you’ll want to have a digital file with pixel dimensions equivalent to a 16×20 @ 300 dpi. You can improvise at lower resolution, but your mileage may vary.
Initial image editing follows a normal path, with ad- justments as needed. Keep a close eye on highlight and shadow detail−remember that you’ll be printing to inkjet film, not paper−and the film is somewhat sensitive to clipping, particularly in the shadows.
Flip and Invert
You’ll be making a negative, so of course you’ll flip the on-screen image horizontally, and invert it.
We’ll make one last adjustment to the file before printing the negative−but first, we have to create a test chart and evaluate the results.
Adjust Image Density
HP recommends printing a test chart, and making a test print to set image density correctly. I’ve found that one can in many cases use a shortcut for this. I’ll review the process by the book in summary form, and then describe the shortcut. (Please refer to the HP instructions for full details).
The adjustment for image density enables creation of a negative that will yield a darkroom print with best possible shadow, mid-tone, and highlight values.
Print the 256-step target generated by the HP software. Here’s the original test target:
(The digital test target is printed on the inkjet film, and then a test image is printed in the darkroom.)
You can print from an image-editing application, or directly through the HP Z3200’s Embedded Web Server (otherwise called EWS−Postscript model). Quoting from the manual “If the printer driver is used to send the image to print, make sure to select “no color management” in the application used to print the image and “application color management” in the driver. Select the plug-in preset for the digital negative film type using “HPPhotoSilverNegative 1.0 for clear film, and HPPhotoSilverNegative 1.0d for translucent film. The printing parameters must be “maximum quality,” “no gloss enhancer” and “more passes.””
The figure below illustrates the settings to use when printing using the EWS’s “job submitter” interface.
This “gray” chart negative can now be used in the darkroom to create a print using your silver paper and your standard printing time−once completed, find the patch that yields “paper white”. The “value” of this patch in this case is 200. This value is used to adjust the digital image file when printing the digital negative (described below).
Final Image Adjustments: Printing the Negative
First, go to the Channels palette, and fill the Red channel with black. (Select the Red channel, then Edit> Select All, then Edit>Fill>Black).
Next, click on RGB in the channels palette to reselect all channels. Create a Curves adjustment layer, select the Red channel. Left click, hold and drag the low left point of the line upward until the output level indicates 200.
Generally, an adjustment in the red channel between 195 and 210 will get the job done. Keep in mind that small adjustments may have significant impact on image appearance, particularly in shadow detail and midtone transitions.
Printing On Inkjet Film
Print the negative the same way you printed the test target, above. Please keep in mind that these negatives are a bit fragile; handle the film and printed negative with care. Use lint-free gloves. Carry the negative in a folio with interleaving sheets to prevent scratching.
We used fiber based fine art papers in our darkroom printing. Here are a couple of examples of methodology:
• Silver Halide Paper: ADOX Premium MCC VC FB (glossy)
• Enlarger: Omega Super Chromega D Dichroic II
• Developing: LPD, Hypo cleaning, Selenium Toning,
• Archival Wash and Dry
• Silver Halide Paper: Ilford Multigrade FB Fiber
• Enlarger: Devere 810 w/ Dichroic Head
• Developing: Dektol D 72, Sprint Record Fixer/ Sprint Archive Fixer remover
• Archival Wash and Dry
Prints are made using a contact frame. You can purchase one or simply adapt an old picture frame as we did. Ensure that the frame is completely flat, and that there are no gaps or spaces between the glass, negative and paper.
Given the size of these negatives and the material used, they tend to attract dust. When possible, handle with lint-free gloves and use a hand-held blower when mounting/dismounting from the contact frame.We also used an archival-style washer that featured continuous low flow of clean water.
We used enlargers listed here for a number of reasons, including the ease of filter selection, and high quality adjustable lenses. On the ADOX paper, for example, we finalized settings of f/22 or f/27, approximately 24 seconds, with mag- enta filter (ranged from 45-80).
Tips and Hints:
The manufacturer suggests that any diffused light source can be used. Certainly we tried this; however I have found that sharper prints can be made with a lens mounted in the enlarger. Another benefit of this setup is that an adjustable aperture makes exposure easier to control.
Use reasonably fresh chemistry. Once you immerse the exposed paper in the developer, try to be patient. It may take a while for the print to come up (be visible) and then the process seems to accelerate a bit to completion. If you’re working with a low-key image, watch the shadows carefully; it seemed that even with the modest contrast of the ADOX that it was possible to over-do and lose detail in this area. I suggest in- process inspection (after initial wash), as you may find that you’ll want to make small adjustments. Some photographers suggest that they like the idea of using dodging/burning to enhance the image in-darkroom, however, it’s a pretty big negative for this. My personal preference is to do as much of the image editing on the digital file− if nothing else, once the adjustments are “locked down” in the digital file, the printed negative can provide very consistent prints.
We also found that image contrast continued to improve, as did some highlight detail, after dry-down. Take a close look at this stage−if you find that shadow/highlight detail, or transition areas are not exactly as you’d like, consider making a small adjustment to the density of the negative using the curves adjustment described above. You might also try adjusting the enlarger filter settings.
It all starts with the negative−it has to hold its own in critical areas. The darkroom work is straightforward− just be sure to attend to the details. We made a number of prints, ranging in size from 8×10 up to 20×24. I feel that image quality was excellent, showing good depth and dimensionality, holding up well in shadow/ highlight areas. One model I had photographed had very fine blonde hair and the detail shown was remarkable. Another image with strong textures held up very well, even at larger sizes. And of course, silver- gelatin fiber-based prints are unequaled for their inherent luminosity and presence!
This process asks that the photographer/printmaker adopt a modified workflow. I found most of this work to be only moderately demanding, with the curves density adjustment requiring a few trial and error cycles before I felt completely comfortable. Overall, the prints looked great and it was well worth the effort!
My sincere thanks to Tony Zinnanti, printmaker, Santa Clarita and Eric Luden of Digital Silver Imaging for their support in this project.
Resources: HP Designjet Z3200 Printer/HP Backlit Film – hp.com; Premium Clear Film® – premierimagingproducts.com; OHP film Pictorico® – pictorico.com; Digital Silver Imaging – digitalsilverimaging. com; Tony Zinnanti – bnr-art.com; Adox Paper – adox.de; Sprint Systems – sprintsystems.com