Cyanotypes






Cyanotypes

The first book of photographs was produced in 1843 by Anna Atkins, who used the cyanotype process discovered by scientist Sir John Herschel (who coined the word "photography"). Atkins placed ferns and other translucent plants on top of paper impregnated with iron-salt and exposed them to sunlight for around 15 minutes, or until an image had formed. The paper was then washed, leaving a fine negative "photogram" on a vivid blue background. The cyanotype was one of the few early techniques to continue into the 20th century, and was also used for architectural drawings, or "blueprints." It remains the most accessible alternative process because you don't need a darkroom and the chemicals are available from specialist suppliers. Some enthusiasts make photograms in the original style; others create negatives on their computers and print them onto acetate or paper made transparent with cooking oil, beeswax, or paraffin. These enlarged negatives are used to contact-print and make positive cyanotypes.

A cyanotype is instantly recognizable by the color that gave the process its name. The pictures tend to be low contrast and often have rough edges. Some earlier examples, such as calotypes (see page38), have paper grain, but the process was used over such a long period that the physical condition and subject matter varies widely. If you can, print on matte, textured paper, as the photosensitive chemicals made cyanotype images part of the paper.

NEGATIVE EFFECT

To imitate a cyanotype photogram, you can scan objects and make them into negatives using an Invert Adjustment layer. This is the kiwi fruit that illustrated the calotype recipe. I also added a labelAtkins's pictures were scientific records.


This old cemetery had fallen into disrepair and was heavily overgrown, making the crooked gravestone an appropriate and interesting subject.

  1. If your original picture is in color, make it black and white using a Channel Mixer adjustment layer (see page 26). In general, favor the Blue channel and aim for a low-contrast image.

  2. In the Layers palette, add a Curves adjustment layer and select Blue from the Channel drop-down menu. Drag the Blue channel's curve upward, but don't close the dialog box.

  3. Select the Red channel and drag its curve downward. Adjust the Red and Blue channels until you achieve a cyan tone that you like. Cyanotypes vary between cyans and true blues to Prussian blues and the slight violet hue of some of Atkins's pictures.

  4. Cyanotypes were relatively stable, though some show discoloration, probably from adhesives. To emulate this, add a new layer and change its blending mode to Color; then select the Brush tool and paint onto the transparent pixels. If you want to simulate chemical staining, use a yellow color.

  5. Another option is to add a rough border. Enlarge the canvas by clicking Image > Canvas Size and adding an appropriate distance to each axis (before you do, check that the Anchor square is in the center with an arrow pointing out on all sidesif not, click in the middle box). Add a new layer and paint around its edges. A quick way to do this is to select the Brush tool and click one corner of the picture, which paints a dot. Then hold down the Shift key and click the next corner, and Photoshop will paint between the two. In this example I loaded one of Photoshop's Dry Media set of brushesthey are nicely uneven and easily achieve the coated paper effect.

This is a 21st-century digital photograph of a 19th-century graveyard, made to look like a cyanotype. If you like this recipe, you may even want to experiment with the original process.




 Python   SQL   Java   php   Perl 
 game development   web development   internet   *nix   graphics   hardware 
 telecommunications   C++ 
 Flash   Active Directory   Windows