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Silver Halide Emulsions, Dye Transfer
> >From: Sil Horwitz [SMTP:silh@earthlink.net]
> >Sent: Monday, March 27, 2000 12:11 PM
> >To: alt-photo-process-l@skyway.usask.ca
> >Subject: Re: Chlorobromide & Dassonville Charcoal black paper
> >
> >At 2000/03/27 09:35 AM -0800, you wrote:
> >>First of all since I'm starting from scratch ANY Silver formula would be
> >>interesting. I don't need Ilford's secrets. Is this Silver Cloride
contact
> >>speed formula that secret? I'm sure the chemists on the list already
have
> >>an idea what is in it. silver nitrate, etc
Here's some info on my Dye Transfer matrix emulsion. This could help you
with general info on emulsion mixing and coating. If you leave out the
yellow dye, this emulsion could be used for other purposes.
Dye Transfer Formulations
By James Browning
603.448.6241
Matrix Film Formulation
I developed the following matrix film with the generous help of Rae Adams.
This is a conventional Iodobromide emulsion, which has been adjusted for
moderately high contrast, but without sacrificing tonal linearity. This
emulsion works quite well. You will have to develop your seps to a higher
gamma than when working with the Kodak materials. The film is about the
same speed as the old Kodak matrix film.
Making the emulsion requires a system for heating a five-liter container
(Stainless), and maintaining the temperature accurately. A burette
suspended over the container is used to slowly drip solution B into solution
A over long periods of time. A paddle stirrer is also mounted over the
reaction vessel, and run at slow speed.
The following formulation (Trial # 20) is for four Liters of emulsion:
Solution A:
Potassium Bromide 168 g
Potassium Iodide (5% solution) 62.4 ml
Inert Gelatin
160 g
Distilled Water 3500
ml
Solution B:
Silver Nitrate
160 g
Distilled Water 500ml
Solution C: (for 500 ml of emulsion)
Sodium Thiosulfate (0.1% solution) 10 ml
Gelatin
30 g
(Gelatin added directly to the heated emulsion)
Solution D: (for 500 ml of emulsion)
Potassium Bromide (1% solution) 10 ml
Manganous Sulfate (1% solution) 10 ml
7-Hydroxy-5-Methyl-1, 3,4-triazaindolizine
(1 % solution pH 7.2) 7.5 ml
Acid Yellow Dye # 23 (Tartrazene) 1.5 g
Triton X-200
5 ml
Sorbitol
2.5 g
Note: Adj. pH of triazaindolizine solution to 7.20 by adding Sodium
Hydroxide.
* Emulsification / Physical Ripening
Add B (at 55 deg. C) to A (at 55 deg. C). Use a burette over a heated
beaker holding solution A at 55 deg. C. Stir the solution using a paddle
mixer. (Approx. 120 rpm). Temperature must be controlled to 1 deg. C using a
temperature controller and hot plate.
Addition as follows:
Add 10 ml of B to A in 5 seconds.
Wait 1 minute
Add 245 ml of B to A over 4 minutes.
Wait 10 minutes
Add 245 ml of B to A over 5 minutes.
Ripen additional 15 minutes
Immediately chill the emulsion using an ice bath. Chill until the emulsion
is very solid, whack the side of the container, there should be a distinct
'jiggle' feeling.
* Washing
Cut the emulsion into 'noodles' 1/4" crossection. Wash using distilled
water for 8 hours. Change water every few hours. Use at least 1 1/2 gallon
of distilled water. Washing is done when current measured by a pH meter
levels out.
The following steps prepare 500 ml of emulsion for coating one sheet.
Note: To prepare a batch of film having matched speed, do the following
steps on the full quantity needed. Multiply the quantities by as many sheets
as you are going to coat. Sensitize the emulsion, and add the final prep.
Filter the entire batch in two stages, first with 40 um filter paper,
followed by 5 um filter paper. Use a vacuum filtration system. Pour the
emulsion into 1L stainless containers with lids, 500 ml per container.
Refrigerate until fully gelled. Remelt the emulsion in one of these
containers, and immediately coat. Use the same procedure for each coating.
* Sensitization (Digestion or Chemical Ripening)
Remelt the emulsion, heat to 60 deg. C. Add the 30-g gelatin to the mix, and
stir until fully dissolved. Add Solution C, mix VERY thoroughly (important).
Stir for 1 hour while maintaining temp at 60 deg. C. Control temp to 1 deg
C. Cover the emulsion with aluminum foil while stirring to prevent fogging
from the safelight. The emulsion's speed increases 1000 times during the
sensitization process.
* Final Prep
Add solution D, mix. The Tartrazene dye is used to absorb blue light to
cause the depth penetration exposure effect and to minimize scattering. A
stabilizing agent is added to prevent fogging, such as the mentioned
triazaindolizine which is available from Alfa Aesar Organics Cat # A18438,
or from Allied Signal. A wetting agent (Triton X-200 from Union Carbide) is
added to promote even coating. The Sorbitol is a plasticizer used to
minimize reticulation, drying marks, and minimize curl. Mix a full batch of
emulsion, and pour into separate containers. Store chilled.
* Coating
Coat 500 ml over a 32" X 50" area. At > 100 deg. F.
* Setting
Set at 50 deg. F for 10 minutes to gel emulsion.
* Drying
Dry in a dust free enclosure for 12 hours at room temperature.
Use care when making the emulsion. Completely scrub the mixing vessel,
beakers, stirring paddle, stirring rods, etc. Use soap, and an abrasive
scrubber. Rinse thoroughly, final rinse with distilled water. Filter the
emulsion with 5um filter paper using a vacuum filter before coating. A
filter must be installed in the coater, placed in a position before the
emulsion passes through the slot. Thoroughly clean all mixing vessels and
other utensils as you go, and carefully clean the coater after a coating run
to prevent buildup of gelatin, which would re-melt into subsequent
emulsions. The coater must be rinsed with hot water between uses. All
coating is best carried out using the light of a sodium safelight, which
provides adequate light for working for long periods of time.
It is helpful to construct a 'noodler' which is used to cut the emulsion
into long strips of 1/4" crossection prior to washing. I used half of a
Besler 4x5 negative carrier. I drilled holes along the opening perimeter,
and threaded fishing line in both directions to form a grid. I force the
emulsion through this grid into a container.
About Gelatins:
The gelatin greatly affects the sensitization of the emulsion. In the
past, less refined gelatins, which contained sulfur compounds were used.
These are termed 'fast' gelatins, and they sensitize the emulsion without
the need to add a sulfur sensitizer. The problem with this is that each
batch of gelatin will have a different effect. In modern emulsions, a
highly refined inert gelatin is used. This allows a controlled sensitization
by addition of sulfur and gold compounds to the mix. I find that the lot
controlled Kind and Knox photographic gelatins work very well. They harden
well in the tanning developer, withstand vigorous wash-off, have low fog
characteristics, and absorb and transfer the dyes readily. Use of other
gelatins will probably yield very different results! I use a low viscosity
gelatin, the Kind and Knox T8042 Bloom 267, Viscosity 41.8. This gelatin
coats well at the concentration specified.
Dye Formulation
The following dye formulations will replace the Kodak dyes fairly
accurately. The dyes have been tested for fade, and perform very well.
Mix a 28% solution of Acetic Acid for pH adjustment.
Mix a 28% solution of Triethanolamine for pH adjustment.
* Add the specified amount of dye in 500 ml of distilled water. Heat to near
boil while stirring until dye is dissolved. Add 1.3 L of distilled water to
bring volume to 1.8 liters.
* Add 1 ml of Formalin 10% to protect the dye from biological growth
* Add 0.5 grams EDTA.
* Adjust pH of the solutions by first adding 10 ml of undiluted
Triethanolamine to the dye solution. Add 10 ml of undiluted Glacial Acetic
Acid. Titrate the solution to the proper pH using the 28% solutions. Add
acid to lower pH, add trieth. To raise pH.
* Top off with distilled water to bring total quantity to two liters.
* Filter.
Acid Blue 45 Acid Red 80 Acid
Yellow 11
Dye pH: 4.17 4.67
4.33 pH
Dye Concentration: 2.4 3.0
5.0 g / 2L
Notes:
Since there is no toe-cutter added to the magenta, you will need to use
Highlight reducer in the first rinse to color balance the highlights. Try
using no HL reducer for the Cyan and Yellow transfers, and for the Magenta
transfer, use a first rinse with 12 ml 1% Sodium Hexametaphosphate added to
1 liter of rinse for one minute. This acts as a toe-cutter.
An alternate cyan dye is Acid Blue 25. This dye is bluer than the Blue 45
and transfers more slowly. It is more light fast than the Blue 45. A less
stable magenta and yellow, which will produce the brightest color, are Acid
Red 289, and Acid Yellow 23. These dyes will produce brighter images, at
the expense of light-fastness.
Check the pH of the dyes frequently, and adjust as necessary. Make sure you
calibrate your pH meter before taking a reading, and use fresh buffer
calibration solutions. Allow plenty of time for readings to stabilize,
particularly with the cyan dye. Filter the dyes frequently to remove
particulate matter.
Replenish the dyes with a solution consisting of the same formulation, but
at four times the concentration; mix the replenisher solution to 500 ml
total. The replenisher should be adjusted to the correct pH. You will have
to experiment to determine the proper replenishment rate. A good starting
point would be to add five times the amount Kodak recommends, this
replenisher is five times less concentrated than the Kodak dye concentrates.
Developing the Matrix Film, and Making a Print
Expose the film through the base (Emulsion down), and develop in the
following tanning developer:
Matrix Film Tanning Developer
Solution A:
Benzoatriazole 5.0 g
Oxalic Acid 40.0 g
Metol 140.0 g
Pyrogallic Acid 150.0 g
Water to make: 20 L
Solution B:
10 lbs. Sodium Carbonate Monohydrate dissolved in 20L of 120 deg. F water.
Mix 1 part A to 2 Parts B for normal contrast. Develop for 3 minutes @ 68
deg. F. Rinse film in 68 deg. water for 30 sec, and fix in a non-hardening
fixer for 3-min. Rinse in 68 deg. F water for one minute. Wash off
unhardened Gelatin using four of five vigorous rinses at 120 deg. Rinse the
matrix in cold water for one minute. Harden the matrix for 3 minutes in the
following hardener:
Hardener
Formalin 10% 50 ml
Kodak Photo-Flo 5 ml
Distilled Water 2 L
Dry the matrices before use.
If you don't have Kodak Dye Transfer paper, you will need to prepare your
own paper. I have used Ilford MG FB F paper successfully. Fix and wash the
paper completely. Treat it with the Kodak M-1 formula:
Kodak M-1 Mordanting Solution
Part A
Aluminum Sulfate 200 g
Water to 1 L
Part B
Sodium Carbonate 80 g
Water to 1 L
Mix one part B to one part A. Add B to A. Filter out any undissolved
precipitate. Soak paper in mixture for 5 minutes. Wash 5 minutes. Then
immerse in a 5% sodium acetate solution for 5 minutes. Dry paper or immerse
in paper conditioner.
Condition the paper in paper conditioner for about 15 minutes before
transferring the image. This is Bob Pace's formulation:
Paper Conditioner
Triethanolamine 60 ml
Glacial Acetic Acid 19.4 ml
Ethylene Glycol 100ml
Water to make 4 L
Check pH and adjust to 6.0.
Soak the paper in hot water for 5 minutes. Drain, and transfer to the
conditioner. Condition for at least 15 minutes. Drain, and then roll the
conditioned paper onto the transfer board with the emulsion face up.
To transfer a matrix, first soak it in 120 deg. F. Water for one minute.
Then place it in the appropriate dye bath for five minutes. Agitate the dye
bath using a tray rocker. Drain the matrix, and transfer to the first rinse
(1-% acetic acid). Rinse for one minute, drain, and then transfer to the
second rinse (1-% acetic acid). Rinse, drain, rinse again, and move the
matrix to the transfer board along with some of the rinse. Roll the matrix
into contact with the paper. Place a hot towel over the matrix. Let
transfer for 10 minutes for the cyan and magenta dyes, and 7 minutes for the
yellow.
The dyes transfer very well, but as with all matrix film transfers, you need
to maintain the temperature at least at 70 deg. F, with higher temperatures
working better. Soaking a towel in hot water, and placing it over the matrix
will facilitate the transfer. Highlight clarity may be controlled by using a
small amount of the highlight reducer (Sodium Hexametaphosphate) to get the
clearest highlights, near paper white. Use a good quality fiber based
paper - I have used fixed out Ilford Multigrade FB, treated in the M1
mordant.
Kodak Formulations
Here are some alternative formulations from Kodak's Formulas for Dye
Transfer Chemicals CIS-154:
Tanning Developer
To prepare a working solution of part A, mix 14.1 g of Part 1 and 6.0 g of
Part 2 with enough water to make 1 Liter
PART A
Part 1 (two-part formula)
Kodak ELON Developing Agent, fine 6.00 g
Ascorbic acid 2.00 g
Methyl paraben, purified 1.00 g
Potassium bromide 5.00 g
5-Methylbenzotriazole 0.1 g
Part 2
Pyrogallic acid 6.00 g
PART B
Sodium Carbonate Monohydrate 215.9 g
Kodak Anti-Calcium, No 1 10.0 g
Water (120( F) 1 L
Dye Transfer Paper Conditioner
Water, demineralized 579.0 g
Glacial Acetic Acid 35.5 g
Formaldehyde, 37% solution 90.1 g
(12% Methanol)
Ammonia, 28% solution 77.7 g
Ethylene Glycol 264.0 g
Allow the mixture to stand for at least 12 hours before testing to allow the
reaction between the ammonia and formaldehyde to go to completion. To
prepare a working solution, use 250ml of concentrate and enough water to
make 1 liter of conditioner. The pH of the working solution should be set
to 6.0 (by adding ammonia if necessary) at 80 deg. F (26.7 deg. C).
These Dye Transfer formulations are finalized, and I am using these
techniques to make some really nice dye prints from my portfolio. I coat
using a travelling slot coater onto 30x40" sheets of Melenex polyester
stock, and make 10 sheets at a time. The coatings are quite good, but the
coating process does require great care, and cleaniness to get flawless
film. Also, the coater slot is machined to very high tolerances. For more
info on the coating techniques, as well as paper coating, mordants, dyes,
mechanical drawings, electrical schematics, etc. please contact me.
For those who are interested, I am working on importing materials from ECCO
Sas of Florence Italy. This may be of interest to alternative process fans,
so I want to help them out with these difficult to find items. Ecco makes
a great hand-operated coater for coating paper and film, as well as a nice
Baryta Base, Cotton Base, undercoatings, and Bergger liquid emulsion for
B&W use. Please feel free to contact me if you have any questions about Dye
Transfer, or the Ecco products. Thanks - Jim
james.browning@valley.net
603.448.6241