Problem of oxidation on B&W prints : LUSENET : B&W Photo - Film & Processing : One Thread

I am currently in my final year at the ENS Louis Lumiere (one of two french Photography schools) and am conducting research into a process of silver oxidation, the causes of which remain unexplained. This process affects black and white prints(RC or FB) notably on warm tone papers. The silver oxidation is characterized by a yellowing and sometimes silver mirroring along the lines of contrast between high and low lighting and can appear partially or cover the whole image. It seems to depend on the storage and viewing conditions. It is surprising because of the speed at which it develops, becoming apparent in only a few weeks or a few months in some cases, and because it usually appears on prints which have been treated with the utmost care. If you have ever encountered this problem, I would be very grateful if you could answer the following questions which would help me in my research. Thank you in advance. QUESTIONNAIRE : Which paper did you use ? Make / Type : RC ou FB : Which fixer did you use ? Make / Type : Dilution : Fixing time : Number of baths : How did you wash your prints ? Kind of water ( tap, treated, filtered, …) : Characteristics of the water : Temperature ( in C ): Washing time : Did you use a wash aid ? Yes / No If yes, Dilution : Make / Type: ( He1-hyposulphite elimination- / washing accelerator / stabiliser) Did you use a washer ? Yes / No If yes, Vertical ? Yes / No Make / Type : Did you use a toner ? Yes / No Kind of toner : How did you dry your prints ? In the open air : Yes / No If yes, how : using blotting paper : Yes / No If yes, type : Did you use a cooler ? Yes / No If yes, Name / make : How did you flatten your prints ? (In the) cold (state) : Yes / No If yes, Between pasteboards : Yes / No If yes, type : ( In the) hot (state) : Yes / No If yes, Name / Make of the press : Temperature ( in C) : Kind of pasteboards : Did you exhibit your prints ? Yes / No If yes, How long did you exhibit them : Description of the place where they were exhibited Geographic situation : Time of the year : Air conditioning : Illumination : Type of frame ( wood, aluminium…) : Were the pictures framed by a professional ? If yes,could you give me his/her name, address and phone number : If no, Type of pasteboard Name / Make : Type of adhesive ( Name / Make) Adhesive tape : Yes / No Corners : Yes / No Spray glue : Yes / No Heat sealed film : Yes / No If no, what were the conditions of storage ? Length of storage : Description of the place where your prints were storage : In the dark ? Yes / No Type of storage ( plastic envelope, Permanent paper, crystal, natural pasteboard or Special archive cardboard, picture albums …) : Name / Make : Were your prints in direct contact with each other ? Yes / No Environment of the prints : Illumination ( fluorescence, tungsten, natural light…) : Room Temperature (in C) : Relative humidity : observation of the phenomenon : colouring of the oxidation : type of oxidation(partial or total, in the high lights,low density…) : How long did it take to you to become aware of the phenomenon ? Remarks :

-- Celia Bonnin (, December 11, 2000


Personally, I have never encountered that problem, but as I am preparing an article about the stability of (not only) RC papers for an online magazine, I have seen some examples of damaged prints. (I am indebted to three gentlemen of Agfa who took the time to present the examples to me, and to explain the cures.) So I can give you a few qualitative hints and keep my promise (given in an earlier posting) to disseminate some of the info I collected.

1) You are right in that working to exacting archival standards will not protect you from silver oxidation. Silver, albeit being regarded as a "noble" metal, silver is actually quite reactive, and it doesn't take much to oxidise the silver image.

2) Damage to prints can become visible in as little as a month.(I saw examples of prints ruined in four weeks by hanging them in a barber's shop, i.e. in an atmosphere with a lot of formaldehyde and other solvents - boy, I'am glad I haven't got to work there!)

3) Warm-tone papers having a silver image consisting of finer grains, thus having more effective surface for the oxidants to attack, seem more vulnerable, but the difference is small.

4) The process is accelerated by light, which means that storing your prints in the dark will make them a bit more stable, but eventually, if the air is bad, this will not fully cure the problem.

5) Partial toning in selenium (such as the toning for a better D_max in highly diluted selenium toner) will not protect the image sufficiently. If you tone to get archivally stable images, tone until there is a clear change in image tone, i.e. in strong selenium and/or for longer toning times.

6) For partial toning in gold toner the same holds.

7) Sulfiding toners (such as the bleach-and-redevelopment toners with ferri/KBr bleach and sodium sulfide toner or the polysulfide variant, like Agfa Viradon) do protect the image. It is then as stable as it can get (but brown).

8) There is a product by Agfa, Sistan, which protects the image by precipitating any soluble (= oxidized) silver ion in the emulsion in the form of an insoluble salt. Sistan is basically a potassium thiocyanate solution plus a wetting agent, which is used as the final bath (thus no washing after the sistan treatment). It is said to be compatible with other toning methods (such as partial selenium toning), and also with spotting. There is a more or less equivalent product by Fuji, which is called AG Guard, which, however, appears to be offered on the Japanese market only.

9) No manufacturer of photo paper will give you any guarantee that images made on his paper will last for whatever period, even given proper processing. This is not because the manufacturers are bad guys, it's because they can't take any responsibility for the air quality at the place where the image is hung.

10) RC paper does NOT appear to be inherently worse than FB paper. The problems reported by Ctein in the nineties are said to have been solved by the addition of anti-oxidants to the base during major revisions of the papers in the late nineties. (I am quoting this from one manufacturer.)

Thomas Wollstein

-- Thomas Wollstein (, December 11, 2000.

I have always presumed that the dark prints with detailess shadows, of the old timers (particularly Strand, Stieglitz, and others of the early 20th Century) that one sees in museums is due to oxidation of the silver. That they were probably not printed so dingy. True?

-- Bill Mitchell (, December 11, 2000.

So far as I know, Agfa hasn't provided anyone with any substantiating documentation that Sistan works as claimed. It's agreed that it _should_ work, but apparently no proof is forthcoming.

-- John Hicks (, December 11, 2000.

I encounteered browning problem with Ilford multigrade RC paper as well as Agfa multicontrast RC paper. Kodak developer and Kodak fixer. Prints kept in album are ok, only the prints in glass frames turned brown in about 6 months time. However after treatment with Kodak Selenium toner, all prints seems to be stable.

-- martin tai (, December 12, 2000.

I do custom phogographic framing as well as my own photography. I specialize in photography with the framing. For the past 5 years Bainbridge has had available their line of Artcare mat & mounting board, both in 100% rag as well as pulp boards of various types. This has some kind of 'micropore chamber' that actively traps pollutants that will effect the print. In accelerated againg tests in atmospheres containing sulfur dioxides and other normal pollutants, prints matted & mounted with these boards perform much better than the normal 100% rag, acid free, buffered boards. Take a look at the current issue of View Camera magazine where Michael A. Smith has an article on the matboard. Dramatic differences are shown. This is NOT light fading as the testing is done in the dark. It is the result of aerial pollution and (possibly) outgassing from the prints and/or framing as well. At any rate, I have been using this board for 5 years now & wouldn't want anything else, especially after seeing test results from a number of different sources. It may be one option in trying to protect prints as they are shown.

-- Dan Smith (, December 14, 2000.

I never cease to be amazed at the quality of responses on this forum, in this case to a question that properly belongs on the Printing & Finishing forum (where it was also posted).

I find that I am behind the times on this archival stuff. Where can I find references regarding research about the archival effects of toning? I believe John Hicks mentioned Nishimura--has he published a book? It sounds as though, if I obtain the long-sought split tone effect, I will need to use Agfa Sistan to stabilize the image. But there is also a warning that Sistan has never been tested properly. Maybe we could write to this Nishimura guy and ask if he has tested it, or plans to test it (?).

I used to tone my Oriental Seagull prints in selenium until they turned quite reddish-brown--particularly landscapes (one of those 15 year-old images has been hanging on my wall all this time, with no apparent ill effects). On the one hand, I am gratified that my love of a deeply-toned print has proven to be "the way to go," but I also treasure the three-dimensionality that the split tone effect provides and don't want to give it up as an aesthetic option.

And what about Wilhelm Research? They do all sorts of archival testing, but I find nothing on their site about black and white prints, except a warning against using RC papers. Do you suppose, if a coalition of fine-art photographers wrote to them, they could be induced to do some testing in this area?

-- Ed Buffaloe (, December 14, 2000.

Ctein did some testing of Sistan and reports in his book "Post Exposure". The new version is out now with new information.

-- Terry Carraway (, December 15, 2000.

See below for some info; although it's about microfilm it's relevant. Note the date.

A month or two ago Doug Nishimura posted some new findings and recommendations on, both as just posts and some as Q&A with Richard Knoppow. A search would probably turn those up.

Wilhelm is apparently ignoring everything but printer papers, inks etc, most likely because that's where the money is.

-- John Hicks (, December 15, 2000.

Thanks John. I also found some interesting posts by Doug Nishimura and Luis Nadeau at lists/cdl/1993/author.html. I plan to write a brief article on archival processing for my web site, and include information from these sources, as well as what T. Wollstein has posted here about Sistan. I found another post that referenced one of Robert Chapman's columns in Creative Camera Techniques where he said he had been trying to get some proof from Agfa as to Sistan's effectiveness, but their responses had been insufficient.

-- Ed Buffaloe (, December 21, 2000.

Dear Ed,

I am the responsible product manager for all B&W chemicals at Agfa. This includes SISTAN too. Unfortunately, I did not get any question for some proof. Since I could not find Robert Chapman´s column I cannot answer him. Please could you give me his address or of the creative camera techniques magazine. I could not find it in the internt. Please contact me If you have questions regarding SISTAN. I try to answer your questions or to help you as far as I can.

Kind regards Wolfgang Holz

Agfa-Gevaert AG

-- Wolfgang Holz (, January 10, 2001.

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