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Cyanotype Notes Silvi Glattauer

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Cyanotype Notes Silvi Glattauer Cyanotypes Support notes for hands-on workshop conducted by Silvi Glattauer Health and Safety As with any aspect of art studio work, were we are exposed to harmful substances one must take precautions to ensure safe work practices. These are common sense, But worth outlining: • When mixing chemicals from powder form, wear gloves and goggles. • Wash hands with warm water and soap after working in studio and Before eating or drinking. • Always try and work in well-ventilated areas and make sure you have regular breaks from the studio. • Wear protective clothing, such as an apron, closed shoes and gloves etc. The Cyanotype technique use very toxic chemicals. Always wear gloves and protective safety glasses. Tongs should always Be used when processing prints in photographic trays. What is a Cyanotype? Cyanotypes prints are regarded as an alternative photographic process or historical process. It uses a light sensitive emulsion that is coated on to art paper. This emulsion is then exposed to UV light through a large format negative to reveal an image. Sir John Herschel invented the cyanotype process, also known as the Blue print process in 1842. In 1842 he began using potassium ferricyanide as a light-sensitive coating. The resulting rich deep blue colour, also known as Prussian blue for the watercolour pigment of the same name, is extremely stable. The original cyanotypes that Sir John made in the 1840s are still clear and beautiful. Because the process requires ultraviolet light for exposure, the images are also sometime known as sun prints. Great examples of cyanotypes prints can Be found on the “Alternative Photography” weBsite: http://www.alternativephotography.com/ General list of materials Before you start, get all the items you need together. • Scales • Apron • Measuring spoons (plastic) • Newspaper to cover work surface • Small measuring jug • Cleaning cloths • 3 glass containers for mixing • Brushes or coating rod (Japanese ingredients 'Hake' Brush, or small foam Brush) • Plastic spoons • Bulldog clips • Small containers for mixed • Glass or a contact print frame chemistry (round take-away • Sunshine or a UV light source containers are ideal) • Distilled water • Face mask • Hair dryer • RuBBer gloves Material copyright Silvi Glattauer 1 updated 21/3/19 Papers Any paper you choose needs to be strong enough to hold when washed for extended periods of time. Hot press – for sharper results Cold press – for creamier results Favoured papers for cyanotypes: Sized paper Better - sharper • FaBriano Satine Watercolour 300gsm • Arches Aquarelle Cold press • Saunders Book Coating Brushes Japanese 'Hake' brush Sponge Brush Material copyright Silvi Glattauer 2 updated 21/3/19 Cyanotype Process Formulae & Method Solution A Potassium Ferricyanide 5g Distilled water 50ml Solution B Ferric Ammonium Citrate (Green) 12.5g Distilled water 50ml • Working in suBdued light, prepare Both these stock solutions and keep separately in dark Bottles. Stock solutions will keep adequately for 3 months. • Mix equal parts of solution A & B. Once the sensitiser is mixed, it may only Be optimum performance for aBout two hours. • Coat paper in an even manner and dry with slow heat from a hair dryer. Sensitised area on paper should be a bright yellow colour. • Sandwich the negative and the paper in a contact frame. • Expose to UV light for time determined (see section under “Finding your base exposure time”). A well-exposed cyanotype will appear with the high values a little too dark and the shadows beginning to reverse. • Once the print is exposed, it can Be developed under cold running water for a few minutes, until the highlights have cleared. You should not see any yellow traces from the sensitiser. • When the print is wet, it will still Be a weak, silvery Blue. As it dries it will oxidize and turn a much darker blue. • Air-dry print. • Toning A Cyanotype 1 teaspoon of Tannic Acid diluted in one litre of warm water 1/2 teaspoon of Sodium CarBonate diluted in one litre of water Tannic Acid > water rinse > Sodium CarBonate Times will vary according to result desired. This is very experimental process that will require lot’s of reject prints, time and patience! Finding your base exposure time – Sun or UV Light Box Your goal is to estaBlish the minimum or correct exposure time to create a Dmax (darkest tone possible) on paper with the chosen chemistry. Every light source and every paper combination will require a different base exposure time. It is important to determine this exposure time before working out what type of contrast curve your negative will require. It’s tempting to adjust exposure time if you find that your shadows are Blocking up or that your highlights are blowing out. But if you do adjust your exposure time then the contrast curve will no longer be accurate. Material copyright Silvi Glattauer 3 updated 21/3/19 Be aware these are some variaBles that will affect the process. Be consistent with the following: • Paper type. Every paper will vary slightly in base exposure time. • Chemistry mix (age, dilution, mix, temperature etc.) • Coating method. Single or douBle application, Brush type etc. To determine this time: 1. Coat 4 or 5 strips of paper with your sensitiser. Leave part of the paper without coating. 2. Place your step wedge on the strip, emulsion side down. Make sure your step wedge has a section of clear film around it. 3. Each whole strip of paper needs to Be exposed for a different time. Expose each strip of paper for two minute increments. (Cyanotype start at 4 minutes). Develop each test strips normally. • The first thing you should Be looking for is the first test strip where the two darker printed steps merge together. This will tell you that you have reached a point where additional exposure is not going to give any significant additional print density. • From this test strip, you now know that you need to decrease the exposure time, But By how much? – The correct exposure will have a the same tone in the darkest patch as the clear film. If you can see the edge of the clear film, then your exposure time is too low. • The example Below shows a cyanotype test strip. You can see that the 15 minute exposure time is too long because the last two patches merge as one tone. More exposure is not going to give us a deeper dark tone. The 5 minute exposure time is too short because we can see the edge of the clear film. The ten minute time is just right. We can see a distinct difference between the last two tones, yet we cannot see a difference with the clear film base. • Material copyright Silvi Glattauer 4 updated 21/3/19 Making a negative for Cyanotype 1. Open Your image in Photoshop 2. Turn your image to Black and White 3. Check to make sure you have a full contrast range (use your levels to check this) 4. Size your image to the exact size you would like your final print at 360 dpi 5. Invert your image to make it a negative 6. Apply a compensation curve to lower the contrast of your image. You may need to lower the opacity of this curve depending on the paper type – experimentation is the key. You can download a curves for Classic Cyanotype Formula and New Cyanotype Formula here: https://www.dropbox.com/sh/rqyqip4cg7mrfwd/AAAg3UsSnkyVzIo5UXFm79Zsa?dl=0 Print your image using Inkjet coated transparency film. I suggest Agfa Copyjet film - http://graphicarts.com.au/shoppingcart/products/Agfa-Copyjet-Film.html Suggested Printer settings: **Printer profile - SC-P800 Series Premium Photo Paper Glossy **Rendering Intent – Perceptual **Uncheck Black Point Compensation **Emulsion Down Material copyright Silvi Glattauer 5 updated 21/3/19 Colour Density may change according to the Cyanotype formula you are using. Classic Cyanotype: -25 - You may need to 25 experiment with this based on your Cyanotype formula and paper combination. Finding you base Exposure time: You will need to do this test on each paper and cyanotype chemistry combination. Material copyright Silvi Glattauer 6 updated 21/3/19 STARTING POINTS FOR EXPOSURES – WITH UV FLOURO TUBES or LED strips AND FABRIANO 5 PAPER: Classic Cyanotype – 20 minutes Contrast correction Adjustments - Inkjet films ****The tones of your print will not match the image you see on your computer screen, unless you apply a contrast adjustment**** The most important thing to understand with inkjet films and ANY alternate photographic process, is that every photographic emulsion will create a different contrast range or tonal distribution in the final print. If you want the print to match the image you have on your computer screen, then you will need to work out a contrast correction adjustment that will match the densities you see on your computer screen with those on the print. This can Be done with an adjustment Levels or Curves layer in Photoshop. Important factors for your curve to be effective: 1. CaliBrate your computer monitor – otherwise how do you know that what you see on your screen is correct? 2. Keep your variaBles the same every time you make a print: Paper, chemistry mix, chemistry temperature, exposure unit, base exposure time etc. 3. Keep notes!! ***The joB of your contrast adjustment is to match the printing densities with the image densities**** For this to occur, you will need to customize a contrast adjustment. This adjustment will takes into account your own workflow variables for your printing method. Basically, what you are doing is the same joB that the custom printer profile does on your film. The printer profile bends the image tones so that the film looks just like the screen image.
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