Blueprints (Cyanotypes)

CONTENTS Safety Materials and Equipment needed Simple Step-by-Step Instructions Stock solutions Making Sensitizer and Coating Paper Exposure Processing Notes Other Recipes Paper Negatives Special effects For more information	(click images for larger views)
	blueprint on graph paper, from a high contrast negative of an original etching (83k jpeg)	blueprint from a halftone negative, with resulting moire pattern from being screened again in scanner (20k jpeg)
	blueprint on grayish paper, from streaky fogged negative; infrared original photo (~20k jpeg)	blueprint on light lavender paper (sometimes I like to include the edges and everything) (~20k jpeg)
	blueprint (~20k jpeg)
	commercial blueprint paper (33k jpeg)	commercial blueprint paper (33k jpeg)
	Commercial blueprint paper comes pre-coated and is developed in ammonia fumes. (details below) These are two pages from a book made in 1981. Some fading around the edges of the pages can be seen in the large views. (The reddish-yellowish tint on the right sides is from the scanner being partly open.)

Safety

• These chemicals can be harmful or fatal if swallowed.
• Avoid getting chemicals on skin or in eyes.
• Wash in running water if this does occur, and seek medical help.
• Avoid breathing fumes and dust.
• If you are sensitive, wear mask and gloves.
• Seek medical attention if adverse reactions occur.
• Do not eat or drink while working with chemicals.
• Wash hands with soap and water when done.

Materials and Equipment needed

• Safety Equipment: An apron and rubber gloves are recommended;
  mask and goggles for splattering, airbrush
• A clean surface to work on that can be washed, or put down old newspapers.
• A place for coated prints to dry, in subdued light
• Chemicals: ferric ammonium citrate; potassium ferricyanide; hydrogen peroxide or chlorine bleach
• Measuring cups and spoons
• A container for mixing the soultion
• Plastic spoon, for mixing
• Brushes, for coating sensitizer on paper
• Paper
• Negatives
• A light source and print frame
• A timer or clock
• 2 Trays, slightly larger than the paper size, and running water
• Masking tape
• Pencil for registration, or notes
• A place for prints to dry undisturbed
• Sponge, rag, mop, soap for cleanup

Detailed Instructions

Stock solutions:

• Solution A -
  Dissolve ferric ammonium citrate in water:

  ferric ammonium citrate	120 grams	(or 4.25 oz)
  water	90 ml	(or 3 oz)

  make up to 1 liter (or 1 quart plus ~2 oz)
  (add enough water so there is a total of 1 liter)
  This is organic and will get moldy.
  When this happens, strain mold off before using.

• Solution B -
  Dissolve potassium ferricyanide in water:

  potassium ferricyanide	60 grams	(or 2 oz)
  water	90 ml	(or 3 oz)

  make up to 1 liter (or 1 quart plus ~2 oz)
  (add enough water so there is a total of 1 liter)

• Label containers clearly.

Making Sensitizer and Coating Paper

• Mix one part A with one part B.
  Mix a small amount; only what will be used in a day.
  
  
• About 20 ml (or about 2/3 oz) of solution will coat about five to ten 8"x10" sheets of paper, depending on whether they get two coats, coating method, type of paper.
  
  
• In subdued light (darkroom, indoors with lights off, shades closed, away from direct sunlight), pour or spoon small amount of sensitizer onto paper and spread evenly with brush. Paper can also be dipped into sensitizer in a tray; then drain over the tray, and hang up to dry with a tray underneath to catch dripped solution, so as not to waste chemicals.
  Let dry, undisturbed, still in subdued light. A closet, basement, or storeroom might be a good place.
  
  
• A fan or blow dryer may be used to speed up drying.
  
  
• For a deeper blue, coat the paper twice or even three times, letting it dry between coats.
  
  
• Leftover paper may be stored in darkness for a day or so, but it is best to use it the same day.
  
  

Exposure

• Place negative on dry coated paper, tape edges to hold in place if necessary (especially in multiple exposures), cover with glass or put into a print frame, and expose to light. The negative can be face up or down, just however you want it. A print frame keeps the negative evenly in contact with the paper during exposure. A glass in a hinged wood frame is convenient to use. A simple "print frame" can be made by placing your paper and negative on a board or flat folded cloth in the sunlight and covering it with a piece of glass or clear plastic. Commercial platemakers and blueprint machines have rollers or vacuum systems that keep the negative evenly in contact with the paper.
  
  
• Sunlight, ultraviolet lamp, arc light, commercial platemaker, sunlamp or other ultraviolet light sources may be used.
  
  
• Expose until most of the image turns gray.
  As the print is exposed, the yellow turns to green or blue and finally to light gray.
  Make sure the imageis grayish-looking, not just the edges. Underexposed prints might look a nice solid blue, but when put in water, the whole image can wash away.
  
  
• Exposure varies, depending on light source, method of coating, kind of paper, density of negatives, and other things. A starting test exposurecan vary from a few seconds in a commercial blueprint machine to around 15 minutes in sunlight or hours outside on a cloudy day. It is usually better to overexpose blueprints than to underexpose them. If a print is underexposed, the image could disappear once it is put in water.
  
  
• Make small test prints first to determine the correct exposure.
  
  

Processing

• Develop the exposed print face down in a tray with running water or with agitation . Turn print over and check after a few seconds or a minute. The print will turn blue in water. Leave it in water until details show in shadow areas and most of the yellow has washed off of highlights.
  
  
• To intensify blue color, place prints in a rinse of hydrogen peroxide and water, with agitation, for a few seconds. Try approx. 1 oz (or ~30 ml) hydrogen peroxide to about a quart (or liter) of water and check, using a test print first. If nothing happens, the solution isn't strong enough; add more peroxide to the solution. If the print fades, the solution is too strong. Remove print immediately and rinse in running water. Add more water to the solution before immersing next print.
  Chlorine bleach may be used, instead of hydrogen peroxide, in about the same proportions with water.
  
  
• Rinse prints in running water for about five minutes and hang to dry.

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NOTES:

• Mix small amounts of solutions first, such as 20 ml or 1/2 oz, then mix more as needed.
• The powdered chemicals keep longer than the stock solutions.
• Stock solutions will keep several months or more.
• Unused solutions or coated paper might only last overnight.
• Other recipes with different proportions exist; stronger or more dilute solutions may work better for specific situations.

Another recipe:

Mix and use as above.

Solution A

Solution B

Small amount:

Mix all together, use same day, as above.
20 ml solution makes about five to ten 8"x10" prints.

Paper:

• Use any paper that can stand soaking, such as many watercolor, etching, and charcoal papers, commercial offset cover stock, or heavier sketchbook pages.
  If unsure, test a small paper sample by soaking it in water at least an hour, or overnight, then pick it up and turn it over several times. If it tears easily or falls apart, it is unsuitable.
  
  
• Colored papers may bleed or fade.
  
  
• If the paper is very absorbent or unsized, size the paper first:
  • Mix 1 teaspoon of cornstarch or arrowroot with a small amount of cold water to evenly wet it,
    then add 1 cup boiling water.
  • Brush evenly on paper.
  • Let dry.
  • Spray starch or sizing may also be used to size paper.
  • Many commercial papers do not need sizing.
  • If unsure, make a small test print. If sensitizer immediately soaks into the paper or if the image is very faint or looks like it sank under the surface of the paper, sizing is needed.
  • Put sensitizer on same side of paper as sizing.

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Negatives:

• Continuous tone or line negatives and positives may be made in a copy camera or by projecting small negatives or slides onto sheet film in an easel under an enlarger. Any graphic arts film, line film or copy film may be used, such as Rapid Access, Kodalith, LPD4, QPD4, Kodak EL. See the high contrast film page for more details. These may be obtained from a lithographic supply company. Process film according to manufacturer's instructions, OR
• For continuous tones on high contrast film, use a diluted paper developer such as Dektol (1:1 or even more diluted, such as 1:4 or 1:10), or use halftone screens when making the copy negatives. (see the halftones page for more information.)
• When making large negatives in an enlarger, it may be necessary to project onto a wall or floor, and to make an easel. Use a big piece of cardboard with the film size drawn on it, and some masking tape to hold film if necessary.
• Ortho films require a red safelight. Red cellophane may be used over a yellow darkroom safelight.

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Other methods for making negatives:

• Photocopy images or make computer printouts onto clear plastic (transparencies, overheads).
  Piece together several 8"x10" sheets for larger images. Overlapping edges will show up as less exposed areas on print. If this is undesirable, cut pieces to fit exactly. Secure with tiny pieces of clear tape in unobtrusive places. Or, use overlaps and pieces of tape as part of the design.
  Thin paper printouts may also be used, but will need long exposures, approximately twice as long as needed for clear film. The paper grain might show up in the image.
  
  
• Draw or paint on clear plastic or thin paper. Try black or red marking pen, India ink, film opaque, whiteout, litho crayon, black cattle marker, black oil pastel. Shadings in pencil may or may not not come out well.
  
  
• Use paper or rubylith and cellophane cutouts or make photograms. Opaque materials will block the light and appear as blank spots; transparent and translucent materials will make areas of tones.
  
  

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Special effects:

• Multiple exposures or coats:
  • Multiple exposures, moving or changing negatives between exposures.
  • Multiple coatings of sensitizer - exposing and processing and drying between coats.
  • Use different negatives, varying exposure times, etc, for the different exposures or coats.
  • Layers of gum bichromate in different colors, using different negatives and so on, may be added on top of cyanotype.
  • For best results with registration, preshrink paper by wetting it in warm water several minutes and letting it dry before making the first coating.
  • Line up negatives the way you want them and make registration marks with pencil or tape on the paper before first coating, then line up each negative with the marks for subsequent exposures.
    (my page about registration for lithography may be illuminating, or confusing.)
    
    
• Coat small areas, spatter, or paint designs with sensitizer. Spattering may be done with an old toothbrush or airbrush. Use goggles, apron, gloves for messy or close work. Clean up spills and splatters as soon as you finish.
  
  
• Coat sensitizer over wax resists or crayon drawings.
  
  
• Other surfaces besides paper:
  • Cloth, wood, birch bark, leather, some kinds of plastic, bisque ware ceramics, and other porous, water-immersible materials may also be used.
  • Size cloth with laundry starch or cornstarch, or spray sizing before coating with sensitizer.
  • When coating T-shirts or other clothing, put a sheet of plastic inside the shirt so the sensitizing solution does not soak through to the back.
  • Give very porous objects, such as plaster, a coating of matte spray paint or spray laundry sizing to keep the sensitizing solution from soaking in.
  • Give shiny objects, such as metal or plastic a thin, fine layer of matte spray paint to give the sensitizing solution something to hang on to.
  • Brush on sensitizer or dip items in sensitizer.
  • Tape negatives to three dimensional objects that won't fit under glass for exposure.
  • Coating methods, exposure and processing times may vary; and it might be difficult to get good results with very porous or very smooth, hard surfaces; so experiment with small test images first!
    
    
• Toning:
  
  This toner bleaches out the image and then turns it a dark dull purple.
  
  Solution A
  

  tannic acid	1 tsp	(or 5 ml)
  water	1 quart	(or ~1 liter)

  Solution B
  

  sodium carbonate	2 tsp	(or 10 ml)
  water	1 quart	(or ~1 liter)

  • Place blueprint in soultion A for one minute with agitation
    
  • Take out and rinse in water
    
  • Place print in solution B for about 30 seconds with agitation
    
  • Rinse again in water
    
  • Place print back in solution A, agitate until it turns purply brown
    
  • Wash a few minutes and dry.

  -----------
  
  A similar toner for blueprints:
  
  Solution A
  

  ammonia	15 drops
  water	30 cc	(or ~1 oz)

  Solution B
  

  tannic acid	10 grams	(or 0.35 oz)
  water	1 liter	(or ~1 quart)

  
  Bleach in A; tone in B; wash and dry, as above.

• Commercial Blueprint Paper
  There are some commercial blueprint papers that have a light sensitive emulsion and can be exposed to sunlight, arc light, blueprint machine, sun lamp, and so on, and then are developed in ammonia fumes. Commercial blueprint paper is usually direct, positive paper, since it is made for copying blueprints as positive images. Longer exposures give lighter images and short exposures give dark images. This type of paper can be found at blueprint or printers' supply companies.
  • Commercial blueprint paper is usually fairly fast and may only need exposures of less than a minute, even a few seconds, depending on light source and negative density. As always, make some small test exposures first.
  • To develop the exposed paper, pour some ammonia on a sponge in a cup,
  • place the loosely rolled exposed blueprint paper over the sponge, without letting it touch the sponge (to keep from getting the paper wet),
  • and put a cardboard box over the cup and paper, to contain the fumes.
  • Let it sit a few minutes and then check--it should turn a deep dark blue in a few seconds to minutes.

  Household ammonia will do, and industrial strength ammonia works better but is more hazardous to handle.
  A taller coffee mug or a jar work better than a teacup; the taller sides hold the paper in place.
  This kind of paper fades in light. An image on the wall can fade to a pale lavender-purple in a few months. The images are preserved if kept in the dark. The images at the top of this page are from a book made almost 20 years ago; people page through it but most of the time it sits on a shelf. The edges faded but the centers of the pages have not.

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For more information:

the first two are technical, the others are more general

• John Carroll, E.J. Wall, Franklin Jordan, Photographic Facts and Formulas, Prentice Hall, NJ, 1975
  
  
• L. P. Clerc, Photography Theory and Practice, Pitman Publishing Co., NY, 1954
  
  
• William Crawford, Keepers of Light, Morgan & Morgan, Dobbs Ferry, NY, 1979
  
  
• Robert Hirsch, Exploring Color Photography, Wm C Brown Publishers, Dubuque Iowa, 1989
  
  
• Glen Rand, "Cyanotype on Clay" Ceramics Monthly, September 1979, p48-50.
  
  
• Links to Alt Photo sites and supplies on Oatmeal Box Camera main page.

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email - ekelana at gmail dot com

last update 8-4-03