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1
Intro to Gum Printing
Intro to Gum Printing
::2012/06/11::
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2
St Pauls Photography - Gum Bichromate
St Pauls Photography - Gum Bichromate
::2011/01/14::
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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
Gum bichromate photography
Gum bichromate photography
::2013/05/13::
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5
Gum printing 3
Gum printing 3
::2011/01/04::
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6
Gum printing 1
Gum printing 1
::2011/01/04::
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7
Gum printing 2
Gum printing 2
::2011/01/04::
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8
Gum Bichromate Print
Gum Bichromate Print
::2011/10/01::
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9
What is a Gum Bichromate Print?
What is a Gum Bichromate Print?
::2012/05/28::
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10
gum bichromate process
gum bichromate process
::2014/02/25::
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11
Gum printing 4
Gum printing 4
::2011/01/05::
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12
Gum Printing Experience 2/11/12
Gum Printing Experience 2/11/12
::2012/02/11::
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13
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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14
Photo Developing Using the Gum bichromate Technique
Photo Developing Using the Gum bichromate Technique
::2010/04/18::
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15
Printing Gum Bichromate over Cyanotype
Printing Gum Bichromate over Cyanotype
::2012/12/13::
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16
Eco Gum Print workshop // Roman Tcherpak
Eco Gum Print workshop // Roman Tcherpak
::2013/08/07::
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17
Alternative Photography ตอนที่3 Gum Bichromate (2/3)
Alternative Photography ตอนที่3 Gum Bichromate (2/3)
::2010/04/24::
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18
Gum Prints " The Hastings Collection"
Gum Prints " The Hastings Collection"
::2011/02/08::
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19
Drying gum prints
Drying gum prints
::2012/05/04::
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20
Goma Bicromatada / Gum Bichromate
Goma Bicromatada / Gum Bichromate
::2013/10/04::
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21
Alternative Photography ตอนที่3 Gum Bichromate (1/3)
Alternative Photography ตอนที่3 Gum Bichromate (1/3)
::2010/04/23::
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22
Gum Bichromate
Gum Bichromate
::2014/03/08::
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23
Gum bichromate on paper 2014 07 02 09 31 26
Gum bichromate on paper 2014 07 02 09 31 26
::2014/07/07::
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24
Alternative Photography ตอนที่3 Gum Bichromate (3/3)
Alternative Photography ตอนที่3 Gum Bichromate (3/3)
::2010/04/23::
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25
Gum Oil Printing!!
Gum Oil Printing!!
::2012/11/05::
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26
My Internship Gum Print
My Internship Gum Print
::2011/03/19::
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27
Gum Bichromate C. Rendina
Gum Bichromate C. Rendina
::2010/05/30::
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28
5 gum - Print Ad Translation
5 gum - Print Ad Translation
::2009/08/18::
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29
Gum bichromate 2014 07 02 09 27 55
Gum bichromate 2014 07 02 09 27 55
::2014/07/07::
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30
Gum Arabica helping alleviate poverty in ASALs
Gum Arabica helping alleviate poverty in ASALs
::2013/10/25::
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31
Arabic gum bichromate - preparation
Arabic gum bichromate - preparation
::2013/08/24::
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32
printing on gum paste for YouTube.mp4
printing on gum paste for YouTube.mp4
::2011/03/08::
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33
Guar Gum & Printing Thickeners by Maruti Hydrocolloids, Ahmedabad
Guar Gum & Printing Thickeners by Maruti Hydrocolloids, Ahmedabad
::2013/07/08::
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34
The regulations followed in applying guar gum product in textile printing
The regulations followed in applying guar gum product in textile printing
::2013/12/20::
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35
Custom Company Logo Candy Gum Tins Printed Snap Top
Custom Company Logo Candy Gum Tins Printed Snap Top
::2013/03/14::
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36
Gum Tragacanth
Gum Tragacanth
::2007/05/22::
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37
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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38
THOMAS AND FRIENDS GUM きかんしゃトーマス ガム
THOMAS AND FRIENDS GUM きかんしゃトーマス ガム
::2014/03/28::
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39
My Chewing Gum production printing sleeves Stimorol
My Chewing Gum production printing sleeves Stimorol
::2008/07/14::
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40
Cricut Cake: Cutting Fondant and Gum Paste Basics for Cake Decorating by Cookies Cupcakes and Cardio
Cricut Cake: Cutting Fondant and Gum Paste Basics for Cake Decorating by Cookies Cupcakes and Cardio
::2011/10/03::
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41
Gum shield prototype test print for Evan, Calum and Conor.
Gum shield prototype test print for Evan, Calum and Conor.
::2014/02/06::
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42
Making the Gumoil Print
Making the Gumoil Print
::2011/04/22::
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43
How to Use Gum Arabic
How to Use Gum Arabic
::2014/06/04::
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44
Home of Love Graphic Print: https://gum.co/homeofloveprint
Home of Love Graphic Print: https://gum.co/homeofloveprint
::2014/05/30::
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45
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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46
Tamarind Kernel Powder And Its Derivatives by Hari Om Gum Ind., Surat
Tamarind Kernel Powder And Its Derivatives by Hari Om Gum Ind., Surat
::2013/07/15::
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47
FINI TENNIS-SOUR Lemon/Lime Tennis Ball Gum Review
FINI TENNIS-SOUR Lemon/Lime Tennis Ball Gum Review
::2013/06/04::
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48
The Giz Wiz 1451: A Shtick of Gum
The Giz Wiz 1451: A Shtick of Gum
::2014/01/16::
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49
K8019041 Gum Base Blender
K8019041 Gum Base Blender
::2013/10/09::
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50
Altrafine - Hydrocolloids - Guar Gum, Cassia Gum, Tamarind Gum, Sesbania Gum, Fenugreek Gum
Altrafine - Hydrocolloids - Guar Gum, Cassia Gum, Tamarind Gum, Sesbania Gum, Fenugreek Gum
::2013/07/20::
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RESULTS [51 .. 101]
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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