This articles is a complilation of notes from the Picto Benelux group, edited by Jacques Kevers on the iron-silver processes: Kallitypes, Vandyke brown and Argyrotype.
- 1 I – Let’s not confuse…
- 2 When speaking about Kallitypes on this doc, we solely seek advice from the original process, slightly extra complicated and costlier, but providing extra flexibility for distinction controll than VDB.
- 3 III – Technical descriptions
- 4 B – The Kallitype Course of
- 5 C – Van Dyke Brown (VDB
- 6 D – The Argyrotype Course of
- 7 Bibliography
I – Let’s not confuse…
The fundamental processes being a part of the iron-silver family are the Kallitype, Van Dyke Brown,
And no: Calotype just isn’t part of them. It even doesn’t have something to do with them!
Calotypes have been designed by Henry Fox-Talbot from his ῝Photogenic Drawings῎ and are based mostly on the transformation of silver nitrate by sodium chloride (salt) into silver chloride. Calotypes are primarily negatives – at first, as their low sensitivity required very lengthy publicity occasions, their use was restricted to photograms; later improvements made it potential to use them additionally immediately in cameras. With them, Fox-Talbot threw the bases of the negative-positive system which was used till the arrival of digital images. It needs to be noted that for constructive documents utilizing the identical method, we don’t name them any more calotypes, but salted paper prints, or salt prints.
These processes, based mostly on the photosensitivity of silver salts alone, usually are not the thing of the current document. Those who want to know more about them ought to read ῝Salted Paper: Historical past and Follow῎ drafted by Lionel Turban, edited and translated by Picto Benelux.
Photograph by Dante Cappellani – print: Stanze di Luce
Here, we only will cope with the processes based mostly on the reduction of iron salts by mild. They divide into three huge households: the cyanotypes, the processes based mostly on noble metals reminiscent of platinum, palladium and gold, and eventually the ῝iron-silver῎ household, where silver salts lying in touch with ferrous salts are turned to the metallic state. The last-named family is the precise topic of this document.
Even within this household, confusions usually are not rare. It typically happens that folks consider they are making Kallitypes, whereas in truth they’re using the Van Dyke process – a bit of newer and easier – and conversely. In truth, the term ῝Kallitype῎ regularly turned type of a generic identify for the ῝iron-silver῎ household.
As for the Argyrotype, this can be a far more current method, developed by the British Michael Ware, where silver nitrate is changed by silver sulphamate in the sensitizer. The massive advantage of this course of is that an acid answer can be used, which makes the clearing much easier. Different processes use impartial or basal solutions producing iron hydroxide (rust..) which could be troublesome to remove and affect the highlights of the picture.
With Kallitypes, ferric oxalate is used to sensitize the paper; through the exposure, solely a very faint image will appear, that needs to be processed to seem utterly. Relying on the selection of papers & builders, numerous tints could be obtained: sepia, pink, eggplant and even blacks very close to these of platinum-palladium prints. All issues thought-about, Kallitypes seem the truth is to be nearer to the platinum-palladium course of, whereas Van Dyke Brown (VDB) stays nearer to the Cyanotype process: for VDB, sensitization can also be based mostly on ferric ammonium citrate, and the picture is asking just for a wash after publicity to seem utterly.
When speaking about Kallitypes on this doc, we solely seek advice from the original process, slightly extra complicated and costlier, but providing extra flexibility for distinction controll than VDB.
II – Slightly little bit of history…
As of 1842, Sir John Herschel ( 1792-1871 ) discovered that mild might rework the ferric ammonium citrate in a ferrous state, and that permanent photographs could possibly be shaped by the reduction of a noble salt into metallic there where it was in touch with the ferrous salts. He used prussian blue pigment, mercury, gold and silver, to describe processes which he referred to as respectively: cyanotype, amphitype, chrysotype and argentotype. Absorbed by his different a number of activities, he by no means pushed much additional his investigations, and it took a very long time before others truly carried out processes derived from his argentotype.
Solely in 1889, Dr . W.W.J. Nicol developed and patented the Kallitype course of and its variants, which he referred to as with out a number of originality Kallitype I, II, and III. These variants used salts reminiscent of ferric sodium citrate, potassium oxalate, ferric oxalate, oxalic acid, in addition to numerous builders.
In 1895, the company ῝Fabrik Technischer Papiere Arndt und Troost῎ from Frankfurt patented a course of referred to as “Braundruckverfahren῎ (brownprint) producing sepia prints. This patent describes a mix of ferric ammonium citrate, silver nitrate, tartaric acid and gelatin. This formulation did bear quite a few modifications, and ultimately the gelatin disappeared because the trendy papers ended up being properly sized at production stage.
It needs to be pointed out that the ῝Van Dyke Brown῎ identify only appeared much later, in the direction of the top of the 1930s – the start of the 1940s. The origin of this identify shouldn’t be recognized for positive: some individuals assume that it refers back to the palette of warm colors utilized by the Flemish painter Antoon Van Dyck. Anyway, the identify is actually wrongly used for the method thought-about right here: the ῝Vandyke῎ course of talked about within the early 20th centuries’ literature referred to a photo-lithographic course of used for the making of topographic maps. It was developed by Frederick Reginald Vandyke who was employed by ῝Survey of India῎ (a cartography establishment) in 1889, and ended his profession as director of the Photograph-Litho Service firm in 1923.
The ῝Van Dyke Brown῎ identify turned nevertheless progressively of widespread use, and the term was outlined for the primary time as a photographic method based mostly on an iron-silver salts combination in the Encyclopaedia Britannica of 1961.
III – Technical descriptions
A – The brownprint
This definitely is the least recognized/used course of within the silver-iron family.
a – The ῝Arndt und Troost῎ components
ferric ammonium citrate …………………. 100gr
silver nitrate ……………………………………. 20gr
tartaric acid …………………………………….. 20gr
gelatin …………………………………………….. 15gr
b- ῝Modern῎ version
The sensitizer is just like the one used for VDB , however resorts to using tartaric acid as an alternative of oxalic acid.
To sensitize the paper:
demineralized water“alt-proc” …………………… 30 ml
ferric ammonium citrate ………………….. 2,5gr
oxalic acid ……………………………………….. zero,4gr
silver nitrate ……………………………………. 1,0gr
“alt-proc” Really distilled water is dear and troublesome to get; and anyway, it’s going to nonetheless include chlorides (Cl-) answerable for the formation of the opaque white AgCl precipitate when in touch with silver nitrate. For our wants, an excellent high quality (≤ 1µs) demineralized (additionally referred to as DM or deionized) water does include neither chlorine, nor chloride, and is greater than sufficient.
Dissolve and mix at first the citrate and the oxalic acid, then add the dissolved nitrate beneath subdued mild. It’s potential that a sediment varieties; this can be filtered out. Depart aside in the dead of night for 24-48 hours. If this components doesn’t give sufficient distinction, it can be increased both by sizing the paper with gelatin, or by adding to the formulation a drop of a 10% potassium dichromate answer. In this case, there could be once more a precipitate, that has additionally to be filtered out.
Publicity: solar or UV. Expose as for a Kallitype or a VDB. Only faint traces will probably be seen earlier than processing, as it is the case with Kallitypes.
borax ……………………………………….. 5gr
Immerse the print for 5 to 7 minutes on this tub, with fixed agitation. Borax (as an alternative of straight water for the Van Dyke) is used for the processing; it is quite alkaline and favors the formation of iron hydroxide, which could be very troublesome to remove. The drawback may be lowered by immersing at first the print in a shower of salted water, slightly acidified with a pinch of citric acid.
Fixing: 1 minute in a three% answer of sodium thiosulphate. General, the image will darken, but the highlights will clear.
Rinse: After a primary tub (5 min.) in a 1% answer of sodium sulphite, rinse in operating water for 20 minutes. If no sulphite tub is used, one may need (in case of fairly arduous water) to acidify the water with a pinch of citric acid and to extend the rinse for 40 minutes.
B – The Kallitype Course of
The Kallitype process never was quite common. It acquired some constructive assessments – especially in the USA – but had the dangerous luck to arrive 10 years after the platinum course of with its monumental status, and just before the very fashionable ῝gaslight῎ paper. Neither fairly as permanent as the primary one, nor as consumer friendly as the second, it received a status of instability which was particularly detrimental.
This fame was principally as a consequence of clumsy processing, particularly to dangerous fixing: Nicol in his first formulae used ammonia solely to repair the picture. Issues improved when this was changed, totally or partially, by sodium thiosulphate. Permanence relies upon certainly largely on the entire elimination of the iron salts with an applicable solvent, and of the unexposed silver salts with thiosulphate. It can be further improved with numerous toners. Over time, Nicol’s unique formulae have been strongly modified. They subsequently have just some historic interest, and we won’t delve additional into them here.
The Kallitype is a creating out course of ( DOP), which does not have the automatic masking effect of printing out processes (POP) nor the associated reduction of distinction in the shadows. Its curve presents an extended and common slope, just like that of the platinum course of. A very good Kallitype could be very troublesome to differentiate from a pt/pd print – however much cheaper…
Workflow: Sensitizing – dr ying – publicity – improvement – washing/clearing – firming (elective) – fixing – wash.
Sensitizing tub: While Nicol’s unique formulae introduced in numerous products, with particularly of ammonium oxalate and oxalic acid, the modern method is far easier and incorporates solely 2 substances. Prepare two options (in subdued mild for the silver nitrate):
A – a 10% silver nitrate answer
B – a 20% ferric oxalate answer
Maintain them separated, in brown bottles and away from mild.
When ready to coat, mix equal elements of A and B (avoid contaminating options by dipping a dropper in the other bottle..) for just the amount you want. Mix with a circular motion (as in the event you have been turning a glass of wine..). A Kallitype requires about 20% more merchandise than a platinum print. As a starting base, foresee (A+B answer): for a 10×12,5cm print: 16-20 drops, for a 13x18cm: 1,5ml (or 34 drops), for a 30x50cm: 6-8ml, and for a 50x60cm: 14ml. in case your prints are likely to fade, you possibly can barely improve the amount of A vs B.
The following may be prepared/used too:
– 1 drop of a 1% gold chloride answer per 20 drops of A+B (hotter tones, olive-black)
– 1 drop of a 5% Tween20 answer per 20-40 drops of A+B (better absorption in paper)
Only use Tween20 when really mandatory (with Bergger’s COT320 for example.)
Drying: If utilizing a hairdryer, it is crucial to not blow the recent air immediately on the moist surface. This might fog the highlights. Use the low temperature setting and direct the air stream to the back of the paper. Even higher, use an air fan as an alternative.
Attention! The paper needs to be ῝bone dry῎ earlier than use! By wet climate, a simple air drying, even for a protracted time, won’t be enough.
Publicity: Proceed as traditional, perhaps with the help of a ῝Stouffer῎ (or comparable) step wedge. The exposure shall be shorter than for a pt/pd print, and must be round 1-6 minutes within the sun; you may need to double that point beneath a UV lamp. It all relies upon from several variables in fact: lighting gear, paper, damaging, and so forth.
Improvement: various totally different formulae exist, giving all totally different results (picture colour,…). In fact, when you intend to tone your image, the effect on picture shade is of little importance…
The image showing very quickly when it will get in touch with the developer, it’s important that each one elements of the print are immersed on the similar time. The commonest method is to put down the exposed paper in an empty, clear and dry tray (clear it before every new print) and to pour the developer over it as shortly as attainable.
Use sufficient developer to cowl the complete picture, otherwise there can be a danger of irregular improvement and of exhaustion before the processing is full. Too weak a developer will depart stains on the picture. It is advised to add at the very least 50ml of recent developer after each 500cm2 processed. Additionally it is good to maintain monitor of the variety of prints processed per batch: each developer has its capacity which it is helpful to know.
Even when the image does seem shortly (10-20 seconds), you shouldn’t chorus from extending the event: it’s unattainable to overdevelop, and it’s important that a most of ferric salts are reworked into ferrous salts. Develop during 8 to 10 minutes. The image will appear far too dark, but will clear up afterward.
Watch out that the developer does not develop into alkaline, as this can foster the transformation of the iron in insoluble salts. The acidity must be checked recurrently with pH strips or with a pH meter. As quickly because the pH will increase, add the same acid as already used in the formulation: citric, oxalic or tartaric. It can guarantee a greater conservation of the picture, and cleaner highlights.
Don’t throw away the developer, but maintain it for the further processings; you may need to get it filtered: after some time, a dark sediment of metallic residues will type.
῝Basic῎ developer (black-brown tones)
DM water ……………………….. 1000ml
borax (anhydrous) …………… 100gr
Rochelle salt …………………… 75gr
tartaric acid ……………………. 3gr
For colder tones, improve the amount of borax and scale back the Rochelle salt (potassium sodium tartrate) – proceed inversely for warmer tones. Be careful: borax does not dissolve properly in chilly water: start with 750ml at 30°C.
In truth, this developer is just not the simplest to organize, nor the one giving the cleanest highlights.
The following formulae are often giving more satisfactory results:
Mixed developer sodium acetate/ammonium citrate
A – a 20% answer of sodium acetate (200gr in 1000ml water)
B – a 20% answer of ammonium citrate (200gr in 1000ml water)
To use: 1 part A + 1 half B. Renew 400ml per 2500cm2 processed paper.
Answer A can be changed by:
C – 150gr sodium acetate + 1,5gr tartaric acid in 1000ml water.
Options A, B and C may also be used individually:
A: brown-black photographs
B: warm reddish to maroon photographs, nicely detailed shadows, superb grain
C: neutral black photographs, deeper blacks than with A.
There are various other developer formulae, far too much to be detailed right here.
After improvement it is necessary to take away the yellowish stain, particularly perceptible in the highlights. Additionally it is indispensable, for permanence, to take away all unexposed ferric salts. Begin by rinsing the print throughout 4-5 minutes in demineralized water water added by a hefty pinch of citric acid. Comply with by an immersion in two successive 4 % EDTA baths (5 minutes in every, with agitation), till highlights are clear. As ferric salts remove, the water will get a yellow colour. When the color turns into robust and clearing slows down, get rid of the bathtub: the second replaces the primary one, and a new one replaces the second. For those who should not have citric acid or EDTA, a 7-Up ® will help you out… Rinse before passing to the following stage.
Firming (optionally available)
The firming tub allows to vary the final picture’s colour, but more importantly to improve the permanence of the picture by plating its silver with a more secure metallic. It also helps to scale back the metallic sheen within the shadows, which may be the results of too lengthy a improvement. All of the baths used for pt/pd prints or salted papers can be used. Firming occurs before fixing.
Gold: citric acid 5gr + 1000ml DM water + 5 % answer of gold chloride 5ml. Immerse 5 minutes, or till the result is to your style. With utilization, its action slows down.
Palladium: sodium acetate 2gr + citric acid 2gr + DM water 400ml + 20 % answer palladium chloride ( 30 drops). Immerse 5 minutes, or until the result’s to your taste. After firming, rinse the print for 5 minutes in operating faucet water.’
Fixing – Washing
A lot of the permanence issues come from insufficient fixing and insufficient washing in water that is too alkaline. It will be a pity to have applied yourself up to this stage, just to compromise every little thing now.
Repair: if too acid, it should bleach the picture; if too alkaline, its action won’t be optimum…
sodium thiosulphate (hyposulphite) ………… 50gr
household ammonia ……………………………….. 5ml
DM water …………………………………………… 1000ml
Repair for two minutes – Water rinse for 2 minutes, then immerse 1minute in a 1% sodium sulphite answer – last wash in operating tap water for 30 minutes. – grasp to dry.
Drawback: highlights are stained.
Think about following ideas:
– add Tween20 to the sensitizer
– use acidified DM water for the first rinse earlier than clearing
– use the mixed sodium acetate/ammonium citrate developer
– course of for at the least 5 minutes
Drawback: contrast is mistaken.
– Adding potassium dichromate to the developer may improve contrast, however with the danger of staining your highlights, and your developer is changed perpetually… It is perhaps fascinating in that case to keep at hand several units of developer, every one with a unique content material of 4% dichromate: 4 – 8 – 16 – 24 – 32 ml/l (the higher the proportion, the upper the contrast).
– A colder developer (≥ 20°C) will produce colder tones and more distinction; hotter (30°C), it’s going to provide warmer tones and decrease contrast.
Some usable papers (Kallitype & VDB).
- Arches Aquarelle
- Bergger COT320
- Fabriano Artistico (acidified)
- Canson Crob’Art
- Canson Montval
Photograph Cezar Popescu
C – Van Dyke Brown (VDB
This can be a simplified version of the Kallitype process. This components doesn’t require ferric oxalate and the processing is completed in straight water. It’s in a method the equal of the cyanotype process in the silver salts family. This process nevertheless does not have the Kallitype’s flexibility for contrast controll.
- one single sensitizing tub, easily prepared
- processing in straight water
- fast; relatively brief publicity occasions
- somewhat long tonal scale; toners just like these used for silver printing
Simply because the Kallitype course of, VDB had from the start a nasty fame relating to image permanence. Largely wrongly, as the problems came principally from insufficient processing directions, transmitted from era to era. Once the formation of iron residues throughout processing and their interplay with the metallic silver within the image absolutely understood, as well as the importance of enough fixing and wash, most of its problems could be addressed. It’s a pity that a course of, that is principally fairly simple whereas giving such lovely results, aroused so much distrust…
Workflow: Sensitizing – dr ying – exposure – wash improvement – toning (non-compulsory) – fixing – ultimate wash.
Sensitizing tub: prepare three options A,B,C to be mixed:
Ammonium Iron(III) Citrate ……. 27gr
DM water( room t°) ………………..100ml
Tartaric acid ………………………… 4,5gr
DM water( room t°) ………………..100ml
Silver nitrate ……………………….. 12gr
DM water( room t°) ………………..100ml
Underneath subdued mild, add B in Some time mixing slowly (avoid metallic instruments) and pour the entire into an opaque brown bottle, large enough to include all three elements. Then add C very slowly, otherwise a milky precipitate will type. If that happens, it’d ultimately dissolve, probably after a day or two. If this is not the case, some citric or tartaric acid might be added drop by drop , till the answer clears up. Warming the solution at about 50°C before adding the nitrate may help. Some authors point out that this tub has to mature a couple of days earlier than use; all don’t agree on this level..
Label clearly. The mixture keeps for about one yr in the refrigerator. If a black sediment varieties, it’s unnecessary to filter, simply be careful to take off the required quantity of answer with out disturbing the sediment. If you don’t get the specified densities any more, it’s time to renew your emulsion.
It’s also attainable to keep elements A, B, and C individually and to make use of a dropper to organize just the required amount at the time of use.
Coating of the emulsion: Use your favorite technique, brush or glass rod. Keep away from brushes with metallic elements. Avoid loading the brush too much: the resulting paper crinkling and puddles formation can be a source of issues through the processing. Unfold the emulsion on the whole floor in a single course before starting in the other one, otherwise you’ll have an uneven distribution which can show within the remaining image. As soon because the emulsion begins to ῝arrange῎ (it loses its sheen while observing the surface reflection), it’s necessary to cease the brushwork, in any other case streaks will seem. (If not used to this, it may be good to coach, with a yellow watercolor for example). When all the product is unfold, put the paper aside a couple of minutes earlier than using a hairdryer (set to the coldest temperature). Rinse and dry the comb within the meantime, mopping it on some family paper. Keep away from leaving it on this paper: it might take in chlorinated elements used to bleach the paper. Final recommendation: be certain that the paper is ῝bone dry῎ earlier than coating. If the climate is moist, you may resort to a dehumidifier.
Exposure: VDB is a POP (printing out course of): the image have to be utterly seen after exposure and before ῝processing῎ – the latter will mainly clean the image without darkening it enormously. A slight overexposure is preferable to an underexposure. Using a Stouffer (or comparable) step wedge to make a collection of check strips exposed with 30 second increments might help.
Beneath the solar, the right publicity often is within the range of two to six minutes; a slightly longer publicity shall be needed underneath UV lamps. Given the massive number of variables (merchandise, unfavorable, paper, mild supply) it isn’t potential to offer more exact indications.
῝Wash improvement῎: One of many standard issues is that the image, which appeared appropriately after exposure, appears to weaken and the darkish tones to ῝bleed῎ through the processing or even later. That’s what made the dangerous fame of the method. These issues will not be inherent to the method, however are as a result of inadequate processing.
First wash improvement: it is very important use demineralized water with a pinch of citric acid added. The presence of chlorine or chloramines within the tap water is the primary reason for stained highlights and image fading in the fixer. With using DM water, the milky cloud leaving the print can be clearly less essential. This cloud is silver chloride shaped in response to the presence of chloride ions within the tap water. Hold agitating the print in this tub during 2 minutes.
(Acidification: the amount of acid to be added will depend on the traits of the water. The water must be acid enough to permit an excellent elimination of the iron residues, however not an excessive amount of, with a purpose to keep away from a reduction of the silver’s Dmax. Start by 1,25gr/l and improve regularly until 30gr/l, as much as wanted. Should you can’t get deep blacks any more, you went too far. A pH slightly below 7 is right)
Second wash improvement: fill a tray with faucet water and add a pinch of citric acid. Agitate the print in it for 2 minutes. Continue the wash in operating faucet water for an additional 2 minutes. A slight fading of the picture is normal at this stage; it’ll darken once more within the fixer. The picture will then additionally get a colder tone.
Toning (elective): Some tonings will shield the metallic silver of the image, enhancing its permanence and decreasing its bleaching within the fixer. Additionally they can change the image’s tones.
Gold-thiourea toner (L.P. Clerc): 50ml of 1 % gold chloride + 50ml of 1 % thiourea + zero,5gr tartaric acid + 20gr sodium chloride + water to make 1000ml
Palladium toner: 2gr sodium acetate + 2gr citric acid + 400ml DM water + 30 drops of 20 % palladium chloride Tone the print in both of those solutions till the end result pleases you visually; rinse in operating faucet water for five minutes and fix.
Selenium toner: Combine 1 to 5ml of Kodak Speedy Selenium Toner (or equivalent) in 500ml DM water. Could be utilized earlier than or after fixing. Be careful: it shortly bleaches the image.
After fixing: 2 minutes, however cease as quickly as you discover the image begins to bleach. Then, hypoclear and wash.
Earlier than fixing: dilute the answer 1:100 or 1:200, tone the print for 30-60 seconds but cease as soon as you discover it starts to bleach; rinse, repair, hypo-clear, wash.
Fixing: Repair = 30gr sodium thiosulphate + 1000ml water. If your water just isn’t alkaline (arduous), 2gr of sodium carbonate, or a teaspoon of household ammonia may be added. This can restrain the picture’s bleaching. Be careful! If the fixer is just too alkaline, the elimination of the iron residues risks to be incomplete, and the residual iron (III) will ultimately oxidize the silver in the image.
This fixer being very diluted, will probably be exhausted shortly. It’s advisable to fix in two baths (2 minutes in each) and to switch the second each Eight-10 prints. A slight fading of the print in the fixer is not any massive deal, because the print will dry-down considerably afterwards. However, it’s of utmost importance that each one the residual silver is eradicated. Do subsequently not interrupt the fixing too early…
Remaining wash: The function of the wash is to get rid of the last residues of the fixer. If you wish to accelerate the wash, immerse the print in a 1 % answer of sodium sulphite (or in a half-strength business hypo-clear), and wash in operating tap water for 20 minutes (without hypo clearing: 30 to 40 minutes).
Drawback: the darkish elements of the image appear to῝bleed”
A brown cloud streams out the darkish areas of the print as quickly as it’s in touch with the washing water, or with the fix. Too much sizing in the paper prevents the sensitizer to impregnate the paper’s fibers. Avoid sizing the paper. An excessive amount of sensitizer coated on the paper. if vital: 1st coat, wipe off, dry, 2nd coat, wipe off, dry, expose. The papier was dried too shortly, the sensitizing answer didn’t have the time to soak into the paper’s fibers.
Drawback: stained highlights, print fogged
The alcalinity of the wash improvement tub brought on the formation of metallic compounds which cannot be eradicated: use DM water and citric acid within the first (and if needed, the second) wash improvement tub.
Drawback: distinction is dangerous
- Make another damaging digitally and adapt the curve of the picture: one of the best assure for a superb picture is an accurate damaging.
- Overexposing reduces contrasts; underexposing decreases it.
- The paper needs to be ῝bone dry῎ earlier than exposure; when climate is wet, a easy drying in open air, even for an extended time, won’t be sufficient.
- Expose the paper instantly after drying.
- Exchange the basic sensitizer with following ῝ VanDyke FC ῎ (ferric citrate) answer:
Answer A῝FC῎: 35ml water + 10gr ferric citrate + 10gr citric acid + 2,5gr sodium citrate
Add B and C options , as for the basic sensitizer.
Use: mix various proportions of ῝Basic῎ (Cl) and ῝FC῎ sensitizer :
1Cl + 0FC = 17 steps — 9Cl + 1FC = 15 steps — 8Cl + 2Fc = 13 steps — 5Cl + 5 FC = 12steps. Growing the FC proportion further won’t improve contrast, however scale back velocity (longer exposures). Growing sodium citrate from 2,5gr to 5gr within the 50/50 components will increase distinction by two further steps on a Stouffer step wedge.
- Use Wynn White ‘s Van Dyke reducer:
potassium ferricyanide ……………… 0,25gr
potassium bromide ……………………. zero,20gr
sodium thiosulphate …………………… 5,00gr
DM water to make …………………… 1000ml
Soak the print to be lowered in water, be certain that no bubbles are left, then immerse and agitate within the reducer. The
lighter elements seem to clear first, and contrast increases. Stop before reaching the desired outcome, rinse, deal with for three minutes in a hypo clearing answer, wash for 30 minutes. (please observe that this is also an answer for cleansing stained highlights…).
Drawback: learn how to determine whether the wash is complete?
If unsure, a residual hypo check could be useful:
HypoTest-2: 75ml DM water + 12,5ml acetic acid 28% + zero,75gr silver nitrate + water to make 100ml
After the wash, wipe floor water off a nook of the print with a paper towel (an element that can be hidden or minimize off afterwards), then put one drop of HT-2 on it. Let sit exactly for two minutes, and blot. If no stain is visible, the wash could be thought-about full. It is perhaps a good suggestion to extend the wash considerably – say 20 minutes – to ensure. If there’s a brown or darkish yellow stain, the wash is way from full. Pale beige means progress, but not sufficient. Attention! Remember that the stains are everlasting…
D – The Argyrotype Course of
Mike Ware, having observed that not one of the iron-silver processes was exempt from traps or difficulties, determined in 1990 to develop a extra consumer pleasant method, and his efforts resulted the yr after in a process he referred to as ῝Argyrotype῎. While it’s fairly professional to challenge its ῝historic῎ character, its filiation with the normal iron-silver processes however is sort of obvious.
The drawback inherent to these final named lies in using silver particles, much finer (colloidal silver) than those utilized in trendy silver gelatin emulsions. These particles are also far more weak, which raises monumental issues, and leaves little leeway (neither an excessive amount of acidity, nor excess of alkalinity..) when processing pictures. Within the argyrotype course of, silver nitrate is changed by silver sulphamate which doesn’t cause any silver degradation within the image and allows for using acid (and thus simply eliminated ) substances in the course of the improvement and fixing levels. As silver sulphamate shouldn’t be available and has first to be made, the sensitization process is considerably longer than for the other processes. But after publicity of the adverse, the processing is straightforward as may be: a simple wash and fixing are enough.
– put together following answer:
. sulphamic acid ………………………………… 7gr
. silver(I) oxide …………………………………… 7gr
. ammonium iron(III) citrate, green …… 22gr
. Tween 20 ……………………………………….. 0,2ml
. water to make ………………………………… 100ml
Dilute the sulphamic acid in 70 ml of scorching DM water, add little by little the silver oxide with constant stirring until full dissolution; then add the citrate, with out stopping to stir. Let settle down. Combine properly the Tween20 in the answer and complete with some DM water at room temperature. If extra distinction is wanted, one further gram of sulphamic acid might be added to the 100ml. If a sediment varieties, filter by way of a coffee filter.
– or you may order the ready-made answer from Bostick & Sullivan…
The damaging ought to correspond to at least one allowing for a correct silver gelatin print on a grade 0 paper. Use a brush reserved for this system, or a glass rod, to coat the paper. Having applied the emulsion , watch for three to 10 minutes, in order that the answer has all the time to penetrate the paper. While it’s still moist, place the paper between two acetate sheets without scratches, put the destructive on prime of it and the entire assembly within the printing body, and eventually expose. Ideally, the rate of humidity ought to be round 40 to 80 %.
Publicity: The Argyrotype course of is a POP (printing out course of); the facet of the image appearing after publicity have to be relatively near what the finished picture must be. In fact, it still can change through the potential tonings, the fixing and the drying. It is strongly recommended to overexpose barely.
῝Wash improvement῎: Begin with a rinse of 10 minutes in demineralized water, with at the very least one water change during this time. In case your tap water is sort of onerous or chlorinated, this could trigger problems for the fixing. It’d then be helpful to add slightly citric acid (or some lemon juice) within the first (demineralized) rinsing water, and to extend your wash for an additional 10 minutes. If however problems stay, will probably be necessary to resort to a dechlorinator, a chemical bought in stores specializing in aquariums and aquaculture.
Firming (non-compulsory): Colors are already influenced by the paper’s selection and its price of humidity in the publicity stage.
As for the opposite processes, a toning tub not only can modify the color, but in addition enhance its endurance to the fixer, as well as its permanence.
The conventional toner is produced from two spare solutions, the first being a zero,2 % gold chloride answer, and the second a 2% ammonium thiocyanate one. Add 50 ml of each in 900ml of demineralized water. This tub is reusable. When it appears to expire, add merely 50ml of each solutions to the previous tub: you don’t want to start out one from scratch!
Fixing: 3 minutes in a 2 % thiosulphate tub. You’ll be able to prolong this time if your print is just too dense (overexposed): it can clear up slightly. If the print has effective spotlight details which should be preserved, it may be helpful to add a teaspoon of liquid ammonia to the fixer. Do not do that if your water is already very alkaline.
It happens that the picture begins very quickly to disintegrate in the fixer. This is often as a consequence of the fact that the sensitizer didn’t penetrate properly sufficient into the fibers of the paper. Adding one drop of Tween20 per 20-24 drops of sensitizer will improve the penetration. Add Tween solely at the time of applying the sensitizer, and only to its quantity used for the current picture, and to not the entire bottle of spare answer.
Wash: Wash for a minimum of 20-30 minutes in operating faucet water. The print will flip darker in the course of the drying and return roughly to the tones it had at the time of the wash-development; if a hairdryer is used, it is going to turn even darker.
Papers: Some papers will not be suitable and don’t permit passable results: indelible yellow staining, bleeding of the image even when utilizing Tween20, metallised sheen… In accordance with Mike Ware, solely pure cotton papers, with an inner Aquapel sizing, freed from another additive, are appropriate.
Among the papers giving good results:
- Bergger COT320
- Arches Platine
- Herschel Platinotype
- Buxton from Ruscombe Mill
- Rives BFK
- Canson Crob’Art
- Whatman’s Watercolor
- La Method Photographique – L.P. Clerc, 1947 Publications Paul Montel, Paris
- The Keepers of Mild – William Crawford, 1979 Morgan & Morgan, Dobbs Ferry, New York
- Spirits of Salts – Martin Reed & Randall Webb, 1999 Argentum, Aurum Press Ltd, London
- Coming into Focus – John Barnier, 2000 Chronicle Books, San Francisco
- The E-book of Various Photographic Processes – 2nd ed. – Christopher James, 2007 Delmar Cengage Studying, Clifton Park, USA
- De Kunst van het Fotoarchief – Roger Kockaerts & Johan Swinnen, 2009 UPA (University Press Antwerp), ASP, Brussels, Belgium (Roger Kockaerts is a member of Picto Benelux)
- Guide to Photographic Various Processes – Jill Enfield, 2013 Focal Press, Oxon, UK
- Gum Printing, and different superb contact printing processes – Christina Z. Anderson, 2013 Bozeman, USA
- The World Journal of Publish-factory Images #Eight – February 2003 – Judy Seigel
- The Vandyke brown and Callitype processes – Carmen Lizardo
- VDB, Kalli, & constructing the massive format digital camera – Sandy King
- More about VDB variables/contrasts/toners/ Kalli – coll.