The concept of creating a Digital Negative itself is fairly simple; however doing it well is a little more complex. You could simply create a negative image in Photoshop and print it or use your printer driver software to print a negative image if you printer driver can do that, but both these processes would be wrong, or at least would not result in an optimum Cyanotype print with the best possible tones.
Besides printing a negative image we have a few other things to tend to. First the image also needs to be reversed. That is, it needs to be flipped on the Horizontal plane. The Negative image will be placed emulsion side of the negative to the emulsion side of the paper and then contact printed. This process reverses the image so this needs to be corrected to make sure words read properly and that right hands remain right hands.
Secondly, more importantly and definitely a little more technically challenging is that the tones need to properly be converted, or mapped, to produce a good tonal curve specifically for the Cyanotype process. Your perfect image with great Whites, Blacks and Mid-Tones will not convert perfectly during the Negative Conversion and even if they did, they would be a perfect Negative conversion for printing on standard paper, not on the greatly reduced tonal range of Cyanotype papers.
|Negative Image, Reversed|
I will cover the process I used in detail on my next post “Cyanotype – Curves”. However, some excellent information can be found on the Internet and in some books. Careful with the books however. Although some purport to help you with the Digital Negative and even with Alternative Printing Processes, very few help you with creating curves specifically for the Cyanotype Process.
For my first test I used an image that somewhat represented my project and then did a simple Negative Conversion and only eyeballed the curves to create what I thought would be a better negative based on my days in the darkroom. I then reversed the Negative image (flipped on the Horizontal) and printed my Acetate Negative. Again, I will cover in detail my printing process but for now note that I used the Epson’s B&W settings to get optimum blacks in my Negative.
|Fake Digital Cyanotype, Colors and Density not right but an accurate representation of the details.|
The Negative was printed on what is considered to be the best Transparency Film available for creating Digital Negatives, Pictorico Premium OHP Transparency Film. Note that this overhead transparency film is clean. For creating Digital Negatives for traditional B&W prints and some other alternate processes, White (as opposed to clear) Transparency film is recommended; the Pictorico Hi-Gloss OHP White Film. For testing and to keep costs down I first purchased 8.5x11 inch sheets. I also purchased Sun Art pre-made Cyanotype paper in 5x7 sheets.
Using my printed Negative I laid it overtop (emulsion side down) of the pre-coated paper. Over top of that I laid a sheet of Contact Glass to press the negative and paper together. This was all done in my office, no darkroom required. I place this setup outside on a sunny day for five minutes creating other test exposures of 3 minutes and 10 minutes.
|Scanned Cyanotype, Some detail is lost, colors fairly good. If you enlarge the image you can see some of the diagonal banding from the paper.|
The paper was then developed in a shallow tray of water with running water trickling into the tray. Apparently water temperature can make some differences and so can the addition of other substances to help darken the final image. I tried some tests using Lemon Juice. The results were great considering I didn’t use proper curves for the negatives, the quality of the coated Sun Art paper is less than great, the test exposures were not refined and proper developing techniques were not used.
On the pre-coated Sun Art paper my comment is based on both the cheap very thin paper that is used and on the banding effect that is either caused by their coating process or perhaps by the paper itself. Not sure which. But, used as kids’ projects by moms or teachers these would be very cool and very affordable.
Next post - Cyanotype - The Shoot
© 2013 Francois Cleroux
(Version 1.02 - March 2013)