Workshop of uncommon photographic techniques

Display Schedule

Code	Completion	Credits	Range	Language Instruction	Semester
307DNF	ZK	3	13S	Czech	summer

Subject guarantor

Jiří PETERA, Martin STECKER

Name of lecturer(s)

Jiří PETERA, Martin STECKER

Learning outcomes of the course unit

The workshops are intended to printing copies using special historical techniques Carbon

Carbon is a contact printing process that gives a final image that comprises a pigment suspended in gelatin placed on a final support, usually paper. To make this image a negative is placed in contact with a sensitized sheet of carbon tissue and exposed with an ultraviolet light source. This causes the gelatin to harden directly in proportion to negative densities, i.e. the tissue is hardened more in the shadows than in the highlights. After exposure the tissue is soaked briefly in cool water, then squeegeed into contact with a paper or plastic support. After about 30 minutes the tissue on its support is transferred to a tray of water at about 105° F for development. Once the pigmented gelatin has begun to melt the tissue is peeled from the support and discarded. The unhardened gelatin slowly washes away from the support leaving a relief image.

Mode of study

Place of workshop Beroun, Barrandov 30

workshop terms: 15. - 17. 2. , 8. - 10. 3., 29. - 31.3. 2019

Prerequisites and co-requisites

No prequisities.

Course contents

Stage one: Making carbon tissue

It is recommended that you prepare the pigmented gelatin solution, which I will call henceforth in this article the “glop,” in one-liter quantities. One liter gives a convenient reference point for many existing formulas and provides an adequate amount of solution to make about 10-15 tissues 8X10″ in size, or the equivalent. It is not necessary to use all of the glop in one session since it can be frozen and used at a later date, weeks or even months in the future.

1 Pour 900 ml of distilled water at 65-70°F into a clean wide-mouth container, either glass or plastic. While stirring, add 100 g of gelatin (Bloom 175-250), to the water and allow the solution to sit for about thirty minutes. Plain Knox gelatin from the grocery store works fine.

2 Fill a small ice chest, or some other type of insulated container, with warm water at around 115-125°F. Place the gelatin solution (in its container) in the warm water and allow it to completely liquefy.

3 When the gelatin solution has completely liquefied, stir in 40g of plain white sugar. The purpose of the sugar is to give pliancy to the dry tissue and prevent it from becoming too brittle. In arid climates the addition of 5-10 ml of glycerin per liter of glop can be added in addition to the sugar to prevent the tissue from drying out too much.

4 Add the pigment to the gelatin solution, and stir well. Many different kinds of pigment can be used. With some exceptions almost any pigment that disperses well in water can be used. For this formula I am going to recommend either Sumi or India ink, or a tube watercolor such as Ivory Black or Lampblack. Both Sumi and Ivory give a warm black color, while India ink and Lampblack give a very neutral tone black. The exact amount needed depends both on the specific pigment itself and on both how much contrast you want in the tissue (the more pigment you add, the higher the contrast). For your first try, use about 15-20 g of pigment per liter of glop.

5 Add water to top off the solution to 925 ml and then stir gently for a minute or so. Then add 50 ml of Isopropyl Alcohol to serve as a surfactant, and a few drops of a 30% solution of Thymol in Isopropyl Alcohol as a preservative. Finally, top off the solution with distilled water to one liter.

6 Leave the container of glop in water at about 115-125°F for at least an hour before coating. This should get rid of most of the bubbles stirred up during mixing.

7 Coat a suitable base with the glop. Although paper can be used for the tissue base I recommend a plastic such as Denril Multi-Media Vellum or Yupo, a synthetic polypropylene paper. You can coat either by pouring the warm glop directly onto an oversize base and spreading it with your fingers, or by the use of a frame of flexible magnetic used over a sheet of galvanized steel plate. Either way, make sure that the room temperature is at about 68-72°F for the duration of the coating.

Assessment methods and criteria

The condition of successful completion of the workshops is at least 75% attendance and handover of two works at a common exhibition.

Note

Workshop dates will be determined during the semester

Schedule for winter semester 2018/2019:

The schedule has not yet been prepared

Schedule for summer semester 2018/2019: