Intro to Gum Printing

Channel: HydroHobbit   |   2012/06/11
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1
Intro to Gum Printing
Intro to Gum Printing
::2012/06/11::
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2
Gum bichromate photography
Gum bichromate photography
::2013/05/13::
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3
Making a tri color gum print
Making a tri color gum print
::2013/08/17::
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4
St Pauls Photography - Gum Bichromate
St Pauls Photography - Gum Bichromate
::2011/01/14::
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Gum printing 1
Gum printing 1
::2011/01/04::
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Gum printing 3
Gum printing 3
::2011/01/05::
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7
Alternative Photography ตอนที่3 Gum Bichromate (1/3)
Alternative Photography ตอนที่3 Gum Bichromate (1/3)
::2010/04/23::
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8
What is a Gum Bichromate Print?
What is a Gum Bichromate Print?
::2012/05/28::
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9
Gum Printing Experience 2/11/12
Gum Printing Experience 2/11/12
::2012/02/12::
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Gum printing 2
Gum printing 2
::2011/01/04::
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11
Gum Bichromate Print
Gum Bichromate Print
::2011/10/01::
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12
Gum printing 4
Gum printing 4
::2011/01/05::
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13
Gum Prints " The Hastings Collection"
Gum Prints " The Hastings Collection"
::2011/02/08::
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14
La Stampa alla Gomma Bicromata - The Gum Bichromate Process
La Stampa alla Gomma Bicromata - The Gum Bichromate Process
::2013/10/05::
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Alternative Photography ตอนที่3 Gum Bichromate (2/3)
Alternative Photography ตอนที่3 Gum Bichromate (2/3)
::2010/04/25::
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gum bichromate process
gum bichromate process
::2014/02/25::
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17
Printing Gum Bichromate over Cyanotype
Printing Gum Bichromate over Cyanotype
::2012/12/13::
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18
Eco Gum Print workshop // Roman Tcherpak
Eco Gum Print workshop // Roman Tcherpak
::2013/08/08::
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19
Alternative Photography ตอนที่3 Gum Bichromate (3/3)
Alternative Photography ตอนที่3 Gum Bichromate (3/3)
::2010/04/23::
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20
Gum Bichromate C. Rendina
Gum Bichromate C. Rendina
::2010/05/30::
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21
Gum Bichromate
Gum Bichromate
::2014/03/08::
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22
Drying gum prints
Drying gum prints
::2012/05/04::
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Goma Bicromatada / Gum Bichromate
Goma Bicromatada / Gum Bichromate
::2013/10/05::
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24
Photo Developing Using the Gum bichromate Technique
Photo Developing Using the Gum bichromate Technique
::2010/04/18::
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25
Arabic gum bichromate - preparation
Arabic gum bichromate - preparation
::2013/08/24::
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26
Gum Arabica helping alleviate poverty in ASALs
Gum Arabica helping alleviate poverty in ASALs
::2013/10/25::
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27
Making the Gumoil Print
Making the Gumoil Print
::2011/04/23::
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28
My Internship Gum Print
My Internship Gum Print
::2011/03/19::
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29
5 gum - Print Ad Translation
5 gum - Print Ad Translation
::2009/08/18::
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30
Textile Fabric Printing video 4
Textile Fabric Printing video 4
::2012/03/31::
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31
Custom Promotional Gum Printed w/Logo
Custom Promotional Gum Printed w/Logo
::2012/01/24::
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32
Gum Oil Printing!!
Gum Oil Printing!!
::2012/11/06::
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33
Isiolo looks to Gum Arabic for millions in revenue
Isiolo looks to Gum Arabic for millions in revenue
::2013/10/14::
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34
Sunnah IIC Arabic Gum Group
Sunnah IIC Arabic Gum Group
::2014/03/04::
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35
Gum Arabic 5
Gum Arabic 5
::2014/02/25::
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36
05 - Positive Photo Plate Lithography - Prepping Plate for Storage - Gum Arabic - part 02
05 - Positive Photo Plate Lithography - Prepping Plate for Storage - Gum Arabic - part 02
::2013/09/08::
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37
Painting Watercolors- Gum Arabic vs. Lifting Preparation
Painting Watercolors- Gum Arabic vs. Lifting Preparation
::2011/10/06::
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38
Gum Arabic 6
Gum Arabic 6
::2014/02/25::
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39
gum arabic kibbling hammer mill supplier
gum arabic kibbling hammer mill supplier
::2014/01/09::
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40
The true story of GUMDAM, half gum, half machine.
The true story of GUMDAM, half gum, half machine.
::2010/09/24::
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41
Nexira
Nexira's Mathieu Dondain on the acacia gum market
::2012/01/12::
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42
Arabic Gum Gravity Separator in Nigeria
Arabic Gum Gravity Separator in Nigeria
::2012/03/18::
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43
gomme bichromatée portraits écrits 11_13
gomme bichromatée portraits écrits 11_13
::2013/11/12::
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44
Chad Gum Arabic
Chad Gum Arabic
::2012/07/31::
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45
Indian Gum-Arabic Tree or Babul (Herb Therapy)
Indian Gum-Arabic Tree or Babul (Herb Therapy)
::2010/11/27::
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tirage gomme bichromatée
tirage gomme bichromatée
::2012/04/25::
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Gum Arabic 3
Gum Arabic 3
::2014/02/25::
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Gum Arabic harvesting basta
Gum Arabic harvesting basta
::2012/09/10::
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Formulary 2008 Platinum/Gum/QTR Workshop
Formulary 2008 Platinum/Gum/QTR Workshop
::2008/09/07::
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Gum Arabic 8
Gum Arabic 8
::2014/02/25::
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From Wikipedia, the free encyclopedia
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Gum printing is a way of making photographic reproductions without the use of silver halides. The process uses salts of dichromate in common with a number of other related processes such as sun printing.

When mixtures of mucilaginous, protein-containing materials together with soluble salts of dichromate are exposed to ultraviolet light, the protein content becomes tanned and resistant to solution in water. The untanned material can be washed away in warm water leaving a hardened, tanned protein negative.

For gum printing a solution of gum arabic is mixed with either potassium or ammonium dichromate. The higher the proportion of dichromate, the more sensitive the mixture. However, increasing the concentration of dichromate also reduces the contrast which is very low at best. The right concentration of dichromate is always a compromise between speed and contrast.

Using ammonium dichromate allows concentrations up to 15% of the active ingredient whereas potassium dichromate is limited to about 10%. Exceeding these concentrations results in deposits of chromic acid in the dried film which ruins any attempts at printing. The greatest sensitivity expressed as an ASA speed rating is estimated to be about ASA 0.003. The resulting mucilaginous mixture is spread on a suitable base and allowed to dry in the dark. A contact negative the same size of the finished print is then placed on top of the dried coating and exposed to an ultraviolet light source, typically bright sunshine.

Often more than one negative is used to provide detail in all tonal ranges. Using multiple exposures requires very careful registration. In exposing the paper, the thinnest parts of the negatives will allow the most exposure and cause the areas to be darker. The densest parts of the negative require more exposure.

The exposed print is then developed gradually in a succession of trays of still water (approximately ten minute intervals) at room temperature until the bath water is clear. The gum is soft and easily removed at this stage. The negative is then carefully dried when the negative image will be visible as raised areas of clear colourless gum. This surface can then be inked using proprietary oil based printing ink and impressions made using a simple pressure printing press. Each negative can be made to yield several copies or even copies in different colours. However the fragile nature of the dried gum surface usually will restrict re-use to only one or two copies.

See also[edit]

References[edit]

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