Christina,
Thank you very, very much for taking the time and effort to post the cuprotype process. It is always exciting to discover a new alternative process and I intend to follow up on this.
Bob Schramm
Check out my web page at:
http://www.SchrammStudio.com
> Date: Wed, 31 Oct 2007 19:51:47 -0600
> From: zphoto@montana.net
> Subject: Re: My (first ) try with Jim Patterson Cuprotype-question
> To: alt-photo-process-l@usask.ca
>
> CUPROTYPE (Obernetter's Process, Ferrocupric Process, Copper Print)
> by Jim Patterson 10-5-2007
>
>
>
> J. B. Obernetter developed his process in 1864. The original formula is
> noted in Jan Arnow's "Handbook of Alternative Photographic Processes",
> 1982, page 113.
>
> "Copper Print" is from a 1978 Popular Photography "How to" guide. See
> http://pinhole.stanford.edu/cp.htm for details.
>
>
>
> GENERAL: A contact printing photographic process analogous to Cyanotype;
> full size negative, print frame, UV exposure. The image is reddish-brown
> copper ferrocyanide. All solutions are w/v (weight in a final volume),
> dissolving each salt completely before the next is added, in 10% less water
> than the final volume. Make up to final volume when all salts are
> dissolved. Use very pure chemicals and distilled water, and plastic or
> glass trays, vessels, stirring rods, etc. Try these processes at your own
> risk. The chemicals can cause property damage, environmental damage,
> personal injury, or even death. Store the stable solutions in brown glass
> bottles, plastic caps, plastic cap liner (corrodes metal). Damp coated
> paper (high humidity) may damage negatives. Use kitchen plastic wrap
> between the negative and paper if needed. Sunlight and florescent light fog
> the coated paper. Agitate trays during processing.
>
>
>
> PATTERSON'S modified Obernetter's Process (MO3)
>
>
>
> SENSITIZER: 100 ml distilled water
>
> (Stable) 12grams ferric ammonium citrate (green)*
>
> 12 grams copper sulfate, hydrated (CuSO4.5 H2O)
>
> *ferric ammonium oxalate & ferric oxalate do not work; precipitate
> with copper.
>
> Light sensitive component; mix in safelight area (yellow bug light,
> tungsten)
>
>
>
> DEVELOPER: 1000 ml distilled water
>
> (stable) 10 grams citric acid (hydrous or anhydrous)
>
> 10 grams ammonium thiocyanate (NH4SCN)
>
> (can substitute potassium- or sodium-
> thiocyanate)
>
> Or make a 10% C.A, 10% A.T. stock solution and dilute 1 part stock :
> 9 parts water.
>
>
>
> CLEARING BATH: 750 ml distilled water + 250 ml DEVELOPER (1 part
> developer : 3 parts water)
>
>
>
> TONER: 1000 ml distilled water
>
> (Stable) 20 grams potassium ferricyanide (K3Fe(CN)6)
>
> (or make a 20% stock solution and mix1 part
> stock: 9 parts water)
>
>
>
> WASH: 900 ml tap water + 100 ml white vinegar, or add 5 ml glacial acetic
> acid (CAUTION: noxious fumes) to 955 ml water. If your tap water has iron,
> use distilled water to avoid blue staining. This is a 0.5 % acetic acid
> solution.
>
>
>
> Coat paper with sensitizer in a darkened room with yellow bug light or low
> wattage tungsten lights; no fluorescent or sunlight. Dry with forced air
> (fan, no heat) & expose in print frame to UV light until an image is
> present. Work out your own exposure time. I have kept coated (no
> dichromate) dry paper in a dark, dry place for 3 days and it works ok. I
> don't know how long it lasts. I usually coat, dry, and expose the same day.
> Adding a drop of Kodak Photoflo to the sensitizer makes it coat better.
> Tween 20 might work (I didn't have any) but I'm unsure if it's compatible
> with copper.
>
>
>
> Tray develop in DEVELOPER until the shadows clear of orange color and are
> pale gray. About 3-5 minutes. Highlights may have a slight orange stain at
> the end of development. The developer will be slightly orange in color
> (iron salts). One shot developer. Do not save or reuse.
>
>
>
> Place directly into CLEARING BATH, series of 3 tray or solution changes,
> until highlight are clear (paper white) and solution is clear. If you don't
> get all the orange out (iron salts) the print will be blue stained in next
> step. About 5 minutes, longer with thick or unsized papers. The image is
> now copper (I) thiocyanate, which is a dye mordant. (You can stop at this
> point and dye-tone the image with basic dyes (methylene blue, basic brown,
> basic fuchsin, etc) in a 2.5 % acetic acid dye bath (0.1% dye). Wash in a
> 2.5% acetic acid wash and dry. 2.5% acetic acid is 1 part vinegar : 1 part
> water.) Or continue on for the Cuprotype if you are not dye toning.
>
>
>
> Place directly into TONER until fully toned to reddish brown image (About
> 15-20 min). The image is now copper ferrocyanide.) A tray of toner can be
> used for more than one print but discard when it slows, and do not pour back
> into the stock bottle. The thiocyanate from the prints causes it to break
> down. Discard at the end of a work session.
>
>
>
> Transfer to WASH, 3 or more tray or solution changes until highlights are
> clear and solution is clear. Check the back of the paper. About 10
> minutes. Thick papers clear slowly. Thin or dip sized papers clear faster.
> See TROUBLESHOOTING.
>
>
>
> If your tap water is alkaline or hard, final wash in distilled water +
> vinegar as above.
>
>
>
> Dry and marvel.
>
>
>
> CONTRAST CONTROL: Do NOT use potassium chlorate, as the copper chlorate
> that forms is EXPLOSIVE when dry!!! It may be better to tailor your
> negative to the characteristic curve with 1 drop dichromate to clear the
> highlights. I use 30% ammonium dichromate drops (CAUTION: dermatitis,
> carcinogenic; handle carefully), with 0-4 drops in 2 ml sensitizer.
> Ammonium persulfate and hydrogen peroxide do not work. (Just for your info,
> I tried potassium chlorate in a very safe area and it didn't work either.)
>
>
>
> PERMANENCE: USDA tests show that copper ferrocyanide used as a pigment in
> outdoor fences holds up well. Probably as permanent as Cyanotype, and does
> not bleach on light exposure.
>
>
>
> AMIDOL TONING: see the Copper Print http reference. Works fast. 250 ml
> water, 5 grams citric or acetic acid, 0.2 gram amidol. Soak the print for 1
> minute, wash in the WASH and dry. It darkens dramatically to a dark warm
> brown as it dries. I think the copper ferrocyanide acts as a mordant,
> binding the amidol, which oxidizes to the familiar dark brown as it dries.
>
>
>
> GALLIC ACID TONING: Brown image, lower Dmax just as with Cyanotype.
>
>
>
> PAPER: I have used Crane's Diploma Parchment (very sharp image, no
> bleeding, & ferricyanide stain clears easily). Arches Hot Press Watercolor
> Paper (slight texture) and Cold Press (moderate texture) work but are slow
> to clear the ferricyanide stain. (See TROUBLESHOOTING) I am sure other
> papers work, but some do not. Don't use buffered paper or paper filled or
> sized with calcium carbonate or magnesium carbonate as alkalis bleach the
> image. Works on cotton fabric also.
>
>
>
> TROUBLESHOOTING: Low Dmax: double coat the paper, drying between coats or
> size the paper. Blue Staining: Iron contamination of solutions, iron not
> cleared completely in CLEARING BATH, or toner (ferricyanide) was not washed
> out of the print. Increase the clearing or wash times. If a thick paper
> has a yellow ferricyanide stain after a long wash, you can soak it in a
> solution of 500 ml water, 5 grams acetic acid, 5 grams zinc sulfate & 5
> grams sodium sulfite, which converts the potassium ferricyanide to zinc
> ferrocyanide, a white pigment used in marine paints. Then WASH to remove
> excess salts and dry.
>
>
>
> ARCHIVAL WASH: Don't! The long alkaline tap water wash will dissolve part
> of the image making it fuzzy or weak. Use tray washes of dilute acetic
> acid.
>
>
>
> MOUNTING & STORING: Don't use buffered mats or papers. See PAPER above.
>
>
>
> EXPOSURE: I use a homemade UV unit of eight, 18-inch black light bulbs from
> Home Depot about 3 inches from the print frame. My exposure time is about 5
> minutes with no dichromate added. 30-150% longer with increasing
> dichromate additions.
>
>
>
> COPPER PRINT: A printing out version. Develops in water. See the http
> reference. I get staining of highlights and bleeding of shadows, but
> Obernetter's gives sharp prints with clear highlights.
>
>
>
> EXPERIMENTAL NOTES: I tried the original Obernetter's formula: Sensitizer:
> ferric chloride, copper chloride, with added concentrated hydrochloric acid.
> Developer: potassium thiocyanate with added concentrated sulfuric acid and
> some senstizer added (why?). Slow process, very long scale and very
> difficult to clear the iron salts. Split tones with reddish brown shadows
> and blue highlights were common, due to cyanotype reaction in the toner when
> all ferric salts not removed in washing. Almost impossible to clear the
> iron with a water wash. The developer is dark blood red and can't see the
> print unless you pull it out of the solution. I don't recommend it.
>
>
>
> I first modified the formula (MO1) to use 1 % citric acid instead of
> hydrochloric acid and sulfuric acid in the sensitizer and developer
> respectively, and left the sensitizer out of the developer. The clearing
> bath I added to get the iron out and keep some thiocyanate ion in the bath
> to keep the copper (I) thiocyanate in the print by common ion effect. It
> is also slow (20 min exposure) but clears the iron out easily. Very fine
> grained smooth image. The 21 Stouffer step wedge gives about 18 steps.
>
>
>
> (OM2) I next tried ferric ammonium citrate to replace the ferric chloride
> with a great increase in speed and about the same long scale on step wedge.
>
>
>
> (OM3) is the process above, with ferric ammonium citrate and copper sulfate.
> If you have very long range negatives, such as an older process with glass
> negatives, the long range of the process without dichromate may match well.
> The best print is probably from a long range negative with 1 drop dichromate
> in the sensitizer to keep the highlights clear and the scale matching your
> negative. Photoshoping the image to match the scale of the process will
> probably work great. With very high dichromate levels the print is grainier
> and much longer exposure.
>
>
>
> The Copper Print is analogous to the New Chrysotype by Mike Ware, in that
> the potassium ferricyanide and copper sulfate are mixed together as the
> sensitizer and the process is mostly a printing out one with washing
> (developing) in water. But without ligands (complexing agents) like
> citrate, acetate, etc., the copper precipitates as copper (II) ferricyanide,
> just as gold does in chrysotype without the 3,3 dithiopropionic acid ligand.
> I tried disodium EDTA alone, sodium citrate (tribasic) alone, ammonium
> citrate (tribasic) alone and combinations with sodium acetate as in the
> reference. The starting weight ratio of copper sulfate, hydrated, to sodium
> citrate is 1:4 which is also about the molar ratio. Speed is fast, but
> staining of highlights and bleeding is a problem, just as with the New
> Chrysotype with low ligand ratios. By increasing the ratio to 1:5 and 1:6
> the staining of highlights is reduced and the contrast is increased, but the
> Dmax is decreased and exposure is increased, just as with the New
> Chrysotype. Also, as with New Chrysotype, the Copper Print sensitizer is
> unstable after mixed and must be coated, exposed and washed (developed)
> quickly. I never got prints as sharp and clean with this process as with
> the modified Obernetter's. I also had great difficulty with ammonium
> persulfate causing a precipitate (potassium persulfate was worse.) Ammonium
> dichromate worked better for me.
>
>
>
> I also coated paper with ferric oxalate 10 % solution and exposed. Very
> fast exposure. (1 min.) This can then be placed in TONER directly for a
> cyanotype, or transposed to copper ferrocyanide by using a reagent of copper
> sulfate, complexed with citrate (1:5 sodium citrate) and ammonium
> thiocyanate The reagent is unstable after mixing and must be kept in
> separate bottles and mixed just before use. It is slow to convert to copper
> (I) thiocyanate, and then it is cleared and toned just as for Obernetter's.
> The image tends to be grainy. Obernetter's has stable reagents and is
> faster to complete.
>
>
>
> The image is redder, grainier, & printing speed faster with increasing pH
> of the sensitizer used. I like the color of the modified Obernetter's
> detailed above. Lower pH sensitizers respond to smaller doses of
> dichromate. Higher pH sensitizers take a lot of dichromate to modify
> contrast. GOOD SOUPING! I know you real photographers can make great
> images with these processes.
>
>
>
>
>
>
>
>
>
> ----- Original Message -----
> From: "Robert W. Schramm" <schrammrus@hotmail.com>
> To: <alt-photo-process-l@usask.ca>
> Sent: Wednesday, October 31, 2007 7:38 PM
> Subject: RE: My (first ) try with Jim Patterson Cuprotype-question
>
>
> >
> > Christina,
> >
> > Tried to google and tried Alt-process-archives but could not find.
> > Could you please repost info on cuprotype. I would much appreciate.
> > Many thanks.
> > Bob Schramm
> >
> > Check out my web page at:
> >
> > http://www.SchrammStudio.com
> >
> >
> >
> >
> >
> >> Date: Tue, 30 Oct 2007 21:02:52 -0600
> >> From: zphoto@montana.net
> >> Subject: Re: My (first ) try with Jim Patterson Cuprotype-question
> >> To: alt-photo-process-l@usask.ca
> >>
> >> Bob,
> >> Google Jim Patterson Cuprotype on the list and I just posted it within
> >> the
> >> last month.
> >> Chris
> >> PS Cor, print is beautiful and Jim (I forwarded him your link) is sooo
> >> pleased that someone used his formula and was successful!
> >>
> >>
> >> ----- Original Message -----
> >> From: "Robert W. Schramm" <schrammrus@hotmail.com>
> >> To: <alt-photo-process-l@usask.ca>
> >> Sent: Tuesday, October 30, 2007 8:48 PM
> >> Subject: RE: My (first ) try with Jim Patterson Cuprotype-question
> >>
> >>
> >> >
> >> > Where can I find the formulas for Cuprotype? This looks like a great
> >> > process.
> >> >
> >> > Bob Schramm
> >> >
> >> > Check out my web page at:
> >> >
> >> > http://www.SchrammStudio.com
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >> Date: Tue, 30 Oct 2007 20:42:38 -0400
> >> >> From: jseigel@panix.com
> >> >> Subject: Re: My (first ) try with Jim Patterson Cuprotype
> >> >> To: alt-photo-process-l@usask.ca
> >> >>
> >> >>
> >> >> On Mon, 29 Oct 2007, C.Breukel@lumc.nl wrote:
> >> >>
> >> >> > Since I have some history with Copper in alternative printing, I was
> >> >> > eager to try Jim Patterson's method.
> >> >> >
> >> >> > I made this quick web site to share my first result and some
> >> >> > observations, hope you like it.
> >> >>
> >> >> Cor, that's a really beautiful print, *especially* considering that
> >> >> it's
> >> >> probably one of the first, possibly even the very first, you did with
> >> >> the
> >> >> process.
> >> >>
> >> >> I myself find the color, at least as it appears on the monitor,
> >> >> especially
> >> >> beautiful. I suppose it doesn't have the cachet of platinum...
> >> >> but maybe it could get a fancy name -- like, say, copper-gold glycee?
> >> >> or
> >> >> Electric Cupratone?
> >> >>
> >> >> I don't recall any mention in the discussion of archivality. How is
> >> >> it
> >> >> in
> >> >> that respect ? (How about "Electric Archival"?)
> >> >>
> >> >> (and how are the twins, et al????)
> >> >>
> >> >> best,
> >> >>
> >> >> J.
> >> >
> >>
> >>
> >
>
>
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