Selenium Toner Impact On Negatives

[Bruce E. Rathbun]

So what is the deal with Selenium Toner boosting negative contrast? After research I find there are so many different claims for dilutions . What is more confusing is the claim that a dilution around 1:32 will increase density while 1:3 will increase contrast. Did I miss something? Increased desnity goes hand in hand with increased contrast. Unless the 1:3 will only impact highlights. Can someone please shed some light here?

-Bruce

[Brian Ellis]

Selenium toning increases the density only of the highlights, the shadows and midtones remain unchanged. And yes, the effect of a change in density is a change in contrast. I'm not aware that different dilutions operate differently, I believe the only effect of a highly diluted solution would be to increase the time it takes for the selenium toning to have its maximum effect. I can't imagine why anyone would use a 1-32 dilution. I've always mixed one part selenium to one part hypo clearing agent because that's what John Sexton teaches in his workshops. At that dilution and around 68 degrees ten minutes is about the longest time you need, anything longer than that will have no effect. There's a discussion of selenium toning negatives in Ansel Adams' book "The Negative."

[David A. Goldfarb]

I find 1:3 for 8 minutes will get you about a one stop expansion in contrast. The time may vary with different films and depending on the type of fixer used.

[Bobby Sandstrom]

Bruce, Brian gave you a condensed version of the John Sexton method. As John states in his workshop book, be sure the negative is thoroughly and properly fixed else it will be irreparably damaged. After toning, place neg in hypo clearing agent for 3 min then wash and dry as you normally do.

[Duane Polcou]

Selenimum toning negatives to increase their overall contrast is perhaps a viable process with
graded papers, but given the extreme contrast flexibility of VC papers, expressly their ability to produce quite a high contrast print, or portion of a print, this toning procedure is outdated.

Ansel liked to tone, aka "intensify", just part of his negatives. The bottom half of his "Moonrise Over Hernandez" negative was sorely underexposed (he exposed the neg to keep detail in the moon - read "Examples: the Making of Forty Photographs") so this area required intensification. By year 2005 VC head/VC paper standards, however, I feel this procedure would be unnecessary.

[Jorge Gasteazoro]

this toning procedure is outdated.

I beleive Bruce is trying out pt/pd and for that selenium toning of negatives can be a god send. It might be the difference from being able to print the negative to just looking at it and wishing you could... :-)

[brook]

How does this work on pyro stained negs? Does it just affect the silver?

[Jorge Gasteazoro]

Yep, it works very good with pyrocat stained negatives, I have never tried it with PMK or ABC, but I see no reason why it could not work.

[paulr]

For a while, I was doing this for routine N+ development. It worked fine, but today I use developer-only methods. I wouldn't hesitate to use selenium if for whatever reason I ended up with a neg that was too soft by mistake. I did find that using selenium left the grain size alone, while increasing development seems to increase graininess. Not an issue for me with t-max, but i was mostly using this treatment on agfa pan.

My formula was:

Rapid Selenium Toner: 110 ml

Hypo Clear Stock: 180ml

Water to make: 1.0 L

This is just a 1:8 solution of selenium in hypo clear. It eliminates separate hypo clear and washing steps.
After fixing, rinse negs for 5 minutes. then agitate in the intensifying hypoclear solution for 5 minutes. Beyond this, I have not seen much additional intensification. In general I saw an increase in contrast equal to N+1 or N+1.5. Capacity is about 40 sheets of 4x5 per liter.

[paulr]

one more thing ... I urge caution if you plan to experiment with anything stronger than 1:8. I have had negs wrecked by selenium solutions that were too strong. as always, YMMV ...

[ronald moravec]

Look up Victor`s Intensifier. It will intensify far more than selenum and can be washed off with fixer. Uses mercury something or other so it is toxic. Keep you fingers out.

Of course so is seleneum.

[Brian Ellis]

With all due respect, Duane is incorrect. Selenium toning doesn't alter the overall contrast of a negative, it increases only the highlight density leaving the midtones and shadows unchanged. For that reason there's a big difference between toning a negative to increase highlight contrast and jacking up the contrast when printing VC paper (or for that matter jacking up the contrast by moving to a higher grade of paper). Using a higher contrast paper, whether VC or graded, has a major effect not only the highlights but also the shadows and midtones of the print. Selenium toning negatives remains a very viable idea in the right situation and and isn't outdated by VC paper.

[David A. Goldfarb]

It also improves the archival qualities of the negative. Selenium toning is standard procedure for archival microfilming, as I understand it.

[Michael Veit]

" it increases only the highlight density leaving the midtones and shadows unchanged. "

Brian, with all due respect, this simply isn't true. Try this: take a junk negative, stick a piece of elctrical tape across an area where it'll mask the full range of negative densities and selenium tone. When you pull the tape off, you'll see that even lower densities were affected. Yes, proportionally, the highlights (in print) are jacked up more, but to say midtones and shadows remain the same just isn't so.

[paulr]

"Look up Victor`s Intensifier. It will intensify far more than selenum and can be washed off with fixer. Uses mercury something or other so it is toxic. Keep you fingers out."

Understatement of the day. You probably don't want anything containg mercuric chloride anywhere near your house. It is more dangerous than anything else used in photography. Selenium isn't in the same league. You would need training that goes way beyond what you can get from a message board to safely handle it. The chemical safety coordinator at my college summmed it up when I asked him about it. "Look--you can work with uranium if you want, with hydrogen sulfide, even with cyanide. But I don't want any mercury compounds on this campus."

"It also improves the archival qualities of the negative. Selenium toning is standard procedure for archival microfilming, as I understand it."

This has been the assumption, but I don't know if it's been demonstrated. Wilhelm's tests pretty much unravelled the idea that selenium does much for print longevity.

"When you pull the tape off, you'll see that even lower densities were affected. Yes, proportionally, the highlights (in print) are jacked up more, but to say midtones and shadows remain the same just isn't so."

Michael is right. Selenium raises contrast, with no change in the shape of the curve that I can see.

[paulr]

Wilhelm's tests may be imperfect (as any simulation will be) but I don't see how they're exactly the same thing as megadosing a rat. Physiology and simple chemical oxidation are different worlds.

At any rate, if assumptions about Selenium's archival powers are true, you would expect a selenium toned print to at least stain more slowly or to a lesser degree when immersed in a sulfide or gold toner. Well, it doesn't. It will tone to a different color, but that's it. This is relevant, because sulfide toning is really just a controlled way of tarnishing the silver in the same way that atmospheric pollutants do. Gold toning, however, seems to have some protective qualities.

Kodak doesn't cite the source of their information, nor do they reveal any methodology. Wilhelm discloses everything. And even though simulations like his are imperfect, they seem to be considered reasonable by conservator. And they're consistent with the experience of anyone who's sulfide toned a selenium print.

[Aaron van de Sande]

Could someobody provide a link or quote from Wilhelm? Every article from him seems to indicate the selenium toning is helpful.

http://www.wilhelm-research.com/pdf/HW_Book_16_of_20_HiRes_v1a.pdf
http://www.wilhelm-research.com/pdf/HW_Book_17_of_20_HiRes_v1a.pdf

Even Ansel indicated that sulfide toning is 'more archival' than selenium. This is old knowledge.

[Aaron van de Sande]

bulletin board did not parse newline correctly

http://www.wilhelm-research.com/pdf/HW_Book_16_of_20_HiRes_v1a.pdf

http://www.wilhelm-research.com/pdf/HW_Book_17_of_20_HiRes_v1a.pdf

[paulr]

Sulfide toning would be a "100 lbs of sugar" argument if you expected it to have zero effect on a selenium toned print. It is reasonable, however, to expect selenium to have SOME effect on the degree or rate of toning. Gold toning has some effect. Sulfide toning itself does. But selenium does not.

There are a lot of common sense assumptions in photography that have never been tested in any rigorous way. A lot of them are about conservation. And some of them have not held up so well. Selenium MAY offer some archival protection. But so far, the one attempt at verifying this that I've seen has come up with nothing. If Kodak sends you anything that resembles a study, please post it.

I'm not sure where you get the idea that Kodak could get sued if their information is wrong. They aren't promising immortal prints, or even prints that will last X number of years. It's hard to imagine that someone could prove they made a specific archival claim that was false and that caused recoverable damages. There are so many variables that you'd have a hard time in court proving anything.

[kthompson]

brown toner is used more with microfilm, and now Silverlock is the things being used in reformatting , although I'm not really sure what they use in the archives of the place I work for. I don't work in that building so I'm not really sure what they use... The archive tech lab (separate from microfilm lab) used brown, polytoner and selenium for years and in the museum lab, we use mainly selenium, polytoner and sepia--mostly for exhibit prints. In the past I have used the discontinued Kodak film, SO-132 for duplicating old negs, and with that film they specified using Selenium. That film and it's predecessors had some longterm stability problems that pretty much ended it's use in archives. Kodak claimed to have solved this problem by this newer version of the film and the inclusion of the selenium and by omitting hypo clear from the processing sequence. By the time SO-132 came out, most archives had quit using it because it's tonal response was pretty bad as well. I have to work with dupe negs on occasion that were made on these films going back from about the mid 50s through the late 70s and they have suffered pretty badly compared to the Plus-X and Super-XX and Ektapan, Pro Copy etc that was also shot at the time--which in many cases looks as good as day one at 50, 60 yrs old. Even 70+ yr old nitrate film looks better many times that this SO dupe film.

Here are some links though for those wondering about those selenium/sulfur microfilm tests...fwiw, I was at a smithsonian conference about ten years ago, and James Reilly from the IPI presented some of this info about selenium and sulfide toners in regards to managing photo collections in archives & museums. During one of his talks, he mentioned that "everythig" should be toned in sulfide or selenium toners.

http://palimpsest.stanford.edu/byorg/abbey/an/an12/an12-5/an12-507.html

http://palimpsest.stanford.edu/byform/mailing-lists/cdl/1993/0376.html

http://palimpsest.stanford.edu/byform/mailing-lists/cdl/1997/1159.html

http://palimpsest.stanford.edu/byform/mailing-lists/cdl/1993/0386.html

[Jorge Gasteazoro]

Paul, I agree with Ken, there is big flaw in Wilhelm tests. Toning has two distinct mechanisms. In one you "resurface" the silver with other chemicals, this is the case of selenium and suilfide toners. They deposit a layer that binds with the silver to create a surface "coat." This "coat" under normal circumstances has a treshold level of light that it can absorb (specially UV light) once you overcome that treshold things deteriorate very rapidly because of the formation of free radicals that "eats away" the selenium/sulfide layer as well as the silver. When you bombard a print with very high levels of light you are in fact overcomeing this treshold that might happen otherwise.

The second mechanism is silver replacement. Metals like Platinum, Palladium, Gold have the ability to replace the silver in the print. Being that they are noble metals and have a high stability the energy required to oxidize them as well as their resistance to free radicals is very high. Even so, if you bombard them with high intensity lights you might still overcome this treshold when the chances of this ocurring normally are not likely. Once you overcome this treshold and specially start the formation of free radicals, things go to pot.

Now lets move on to ink jet posters. Organic materials are very suceptible to free radicals. This is the reason why we use SPF blockers and why you guys are in search of a coatings for your prints. In a sterile environment such as a lab, there are few free radical generating agents. So now we have a two fold problem. One, are you overcoming the treshold level that carbon pigments can support? and two is the absence of free radical generating agents important? In a house hold there are many products capable of generating free radicals by the action of UV light. Bleach, Ammonia, cloroflurocarbons, etc, etc. Apparently ink jet pigments are somewhat stable to the action of UV radiation alone (although much lower than metals), it takes some time to degrade, but is it the same case when a free radical generating agent is present? I suspect this is not the case, and the reason why Wilhelm's tests have been wrong many times. As long as Wilhelm keeps reporting results without taking into account probable chemical interactions in the enviroment, I have a hard time accepting his results as valid.

[paulr]

"I'm having a hard time following this statement. Even if the sulfer can displace 100% of the selenium, that does not mean that selenium offers NO protection under normal conditions."

What I assume people are looking for is a significant degree of protection against oxidation and sulfide staining. What's significant is going to be subjective, so I'm using "noticeable" as a standard. Does a selenium toned print stain less? Does it stain more slowly? Not in any way I can notice. It does stain a different color. Maybe you'll like the color more ;)

I don't remember what Wilhelm's specific findings were. But they were disappointing.

Incidentally, the idea that selenium will protect a silver print is based on a simple assumption: that the silver-selenium compound (whatever it is ... silver selenide??) will be more stable than metalic silver. I haven't seen any demonstrations of this ... just assumptions based on common sense. People assume that since silver isn't completely stable, a compound of silver and something else will be more stable. But it isn't always true. Stability is relative. Pure silver is more stable than some silver compounds, less stable than others, and in some cases, it will likely depend on the specific oxidizing agent.

As far as the legal stuff, what is their specific claim? I think it's odd to trust a statement just because it's from Kodak. I find manufacturers have been a less than trustworthy source of all kinds of information in the past.

[Oren Grad]

Per Ctein's tests, we know that selenium does have a clear and dramatic protective effect on RC prints (as does Agfa Sistan). How long the effect lasts is an open question. Also, it's not clear whether his results generalize to FB; it's conceivable that selenium disproportionately inhibits the specific light-driven reactions that are a characteristic failure mode of the PE-coated papers.

[Aaron van de Sande]

Incidentally, the idea that selenium will protect a silver print is based on a simple assumption: that the silver-selenium compound (whatever it is ... silver selenide??) will be more stable than metalic silver. I haven't seen any demonstrations of this ... just assumptions based on common sense. People assume that since silver isn't completely stable, a compound of silver and something else will be more stable. But it isn't always true. Stability is relative. Pure silver is more stable than some silver compounds, less stable than others, and in some cases, it will likely depend on the specific oxidizing agent.

The heat of reaction will give you a pretty good idea of how stable it is. I am sure that silver selenide is at a lower state than elemental silver. The sulfide is at an even lower state. If you look at the periodic table you will see that oxygen, sulfur, and selenium are all in the same column, so they have similar valience electrons (and form similar compounds)

The oxide is at the lowest state but it doesn't have properties that are good for a negative or print.

[Aaron van de Sande]

Actually I cannot think of any reason why the oxide would be any less desirable in a print or negative. Silver oxide is black. Perhaps we can tone with just hydrogen peroxide?

[Kirk Gittings]

"one more thing ... I urge caution if you plan to experiment with anything stronger than 1:8. I have had negs wrecked by selenium solutions that were too strong. as always, YMMV ..."

I haven't found this to be true. Selenium toning on negatives only goes to completion-about a one zone increase in highlight desity. After much testing, I have been using straight toner for twenty years now. It simply does it faster with absolutely no discernable difference to a slow dilluted tone.

[kthompson]

i don't why I bothered to link to those sites above, but here's another one:

http://www.iaq.dk/papers/iada1999.htm

[Jorge Gasteazoro]

i don't why I bothered to link to those sites above, but here's another one:

I think they are useful, if anything so that people understand that light fastness tests that exclude atmospheric poullutants are misleading. The last 3 links from your previous posts seem to be opinions, albeit by someone who seems knowledgeable in the subject. But the first one and the link you just posted are very good articles IMO. Thanks for "bothering"... :-)

[paulr]

Here are some excerpts from a study by the Image Permanence Institute at RIT.

The good news: selenium toning can improve resistance to oxidation if 100% of the silver is converted to silver selenide. In other words, extreme toning, which you might be able to achieve if you're trying to intensify your negs (although the only negative developing disasters that I've personally had come from trying to do this ... be careful). They also conclude that sulfide toners, particularly those using polysulfides, provide the best protection. The tests were focussed on archiving microfilm.

Interestingly, Aaron, the paper addresses your peroxide question. Apparently peroxide has been traditionally used to test image permanence because of its ability to stain. These researches used various forms of peroxide to conduct all their trials.

"The results of the IPI research led to four main conclusions:

Excellent protection against peroxide attack can be gained by treating microfilm with solutions which lead to the partial sulfiding of the silver image. The best compounds to use, as well as methods of application and possible ill effects on physical properties, etc., are unknown at this point, but there are several promising candidates (in particular, polysulfides), and the direction to be pursued is now clearly established.
Geld and selenium treatments provide protection against peroxide attack only in proportion to the degree to which the heavy metal is substituted for the original silver image. In the absence of sulfiding agents, even very high degrees of gold or selenium substitution do not provide complete protection. In actual practice, when used as recommended, the metal components of gold and selenium toners for microfilm do very little to protect against oxidation; their effectiveness is almost entirely due to the sulfiding action of other constituents of the toner formulas.
Washing of microfilm to extremely low levels of residual thiosulfate, which is regarded as good archival practice, in fact causes film to be substantially more susceptible to peroxide attack than if the washing were less effective. Some form of treatment to protect against oxidation is essential to achieve maximum longevity for microfilm produced with contemporary processing machinery.
As has been reported by others (19), residual thiosulfate can actually stabilize a silver image against oxidation, if present in the right concentration. However, it is impossible in practice to control the concentration by manipulating washing variables. To achieve a reliable degree of protection, film should be well washed, them treated in a controlled fashion with some form of stabilizing bath."

"The peroxide tests at IPI showed that Kodak Rapid Selenium Toner failed to provide protection against redox blemishes, when used as suggested. If highly concentrated solutions were used, the level of protection increased, but was not complete. Such concentrated solutions are impractical for reasons of cost, excessive contrast buildup, and excessive image color change, even if they did provide enough protection. This finding conflicted with numerous published results from Kodak (17,20,21); when we spoke with Kodak personnel, they confirmed that in their own recent peroxide testing with microfilm, the selenium toner was depositing selenium, but not preventing oxidant attack, which it had done in tests performed as recently as one year ago. They suspected that small changes in formulation made by the manufacturing area were responsible, but were not clear on exactly why.

It is our strong feeling that the changes in formulation that suddenly rendered dilute selenium toner ineffective relate to the sulfiding action of minor constituents. Although the formula for Kodak Rapid Selenium Toner is proprietary, it is known to contain both sodium sulfite and hypo (sodium thiosulfate), both of which may be contaminated with small amounts of highly active sulfiding agents. Apparently insignificant manufacturing changes may have caused this active agent to be no longer present; it would still form silver selenide and achieve a toning action (in the sense of color change), but would no longer protect against peroxide. In any case, the surprising ineffectiveness of Kodak Rapid Selenium Toner, together with many other signs of the potency of sulfiding agents, pointed the way to a much different analysis of image stability and how to achieve practical protection against red spots.

One of the strongest clues to the power of sulfiding agents to protect against peroxide came from experiments with gold tuners. Kodak has recommended a formula known as GP-2 since the 1960s for the treatment of microfilm to prevent red spot attack (7,14). Because of the high cost it has seldom been used in practice, but it was always regarded as absolute protection. One of the ingredients of GP-2 is thiourea, a known sulfiding agent. In experiments at IPI, this formula was indeed completely effective in preventing peroxide attack. However, experiments with the same formula without the gold were completely effective. In both the gold toner and the selenium toner, it seemed to be the sulfiding agents, not substitution with gold or conversion to silver selenide, that was providing the bulk of the protection against oxidants.

This was confirmed in another series of experiments where gold and selenium formulas which did not contain a sulfiding agent were used. They "toned," in the sense of depositing gold or converting the silver to silver selenide, but the protection against peroxide was only in proportion to the degree of substitution. Even virtually complete conversion of the silver image to gold did not stop peroxide attack; the small amount of remaining silver discolored in the peroxide test."

full text:
http://palimpsest.stanford.edu/byorg/abbey/an/an12/an12-5/an12-507.html

[paulr]

"I haven't found this to be true. Selenium toning on negatives only goes to completion-about a one zone increase in highlight desity. After much testing, I have been using straight toner for twenty years now. It simply does it faster with absolutely no discernable difference to a slow dilluted tone."

I'm glad to hear this works ... I have no idea why I had such problems with strong dilutions. Possibly I made some other mistake. At any rate, I didn't want to repeat the process to find out. And the problems never showed up at 1:8, so I kept doing that. I just want to encourage anyone experimenting with stronger concentrations to be careful.

[paulr]

Jorge, if I remember correctly, Wilhelm's tests of toners were chemical oxidation tests and not lightfastness tests. But the RIT tests I just posted were exclusively about chemical oxidation.

On inkjet pigments, keep in mind they're not all the same. Piezotone inks use pure carbon pigments which (in theory, anyhow, for whatever it's worth) have the potential of being more stable than silver.

[kthompson]

they were all actually from the same person--Douglas Nimishura (sp?, I can never get it right...) from the IPI. He co-wrote that thing in the Abbey Journal, which was also done in another form on the Consdistlist that you can access through CoOL or subscribe to. James Reilly has also written several books and written papers dealing with these issues as well. If you've seen those kodak books "Conservation of Photography" and "Care and Indentification of 19th Century Prints", those are his. There are some books that deal with this. The out of print--"Collection, Use and Care of Historical Photographs" by the American Assoc of State and Local History, and Dennis Inch/Lawrence Keefe's "Life of a Photograph"--they actually have a chapter on archival film processing and outline a procedure for toning b/w sheet and roll film with gold, sulfide or selenium.

The IAQ site--those people are conservators as well, and some are materials engineers as well and they have links to the IPI as well. They had an excellent research paper about ozone and inkjet pigment & ink deterioration a few years ago. That study was done at the IPI and was also tied in with an ANSI/ISO workgroup that was trying to figure out some new standards for digital ouput--the Consdistlist has many postings about this group as well, with many of the same people.

I don't see this stuff as "opinions" as much as observations from those who are working in the field as conservators and engineers for the manufacturers. Anybody who works in a museum or an archive is going to be seeing some deterioration even within their own collections at a certain point--and they're sure going to see it in the stuff they accession. Whether it's an opinion or a fact--I don't know how they can really come up with a definitive statement if you really choose to get into it. It's like the term life expectancy (LE) in the standards now instead of "archival" because they deem that there is no definitive standard for archival....

then if you allow me to veer off topic here--look at the standards for preservation documentation and how these changing as well. 100 yrs was the benchmark, and then that sort of moved down to 75, and they began accepting RC prints and soon most documentation was actually being done on 35mm rollfilm instead of 4x5 and prints were being made on RC paper instead of fiber. Now all that's a moot point, as this is changing to digital and inkjets. Soon this will be the standard--while most of the people I know working are playing catch-up here as we still shoot film & make prints the old fashioned way, and everything that was governed to us a "standard" has changed almost seemingly overnight--but we all saw it coming...

so you can either do the accelerated tests and extrapolate the results--or you can look at what you actually have and how it was stored over a long period of time and what it looks now. On a side note--this is how I came not to trust many of the "archival" negative sleeves and the like--simply because they didn't hold up under a real time observation by this opinionated photographer....

my opinions only as always/not my employers

[kthompson]

the tests were being done because the problems first showed up in microfilm. Microfilm is THE standard for records retention and reformatting projects in pretty much every government archive in the world since the 1950s. Whatever state or country you live in has a program that records all the public records, and probably most of the regional newspapers as well onto microfilm. Microfilm is the the media that all other forms of "archival" media is measured against. It's like the canary in the coalmine. Many of these institutions are going into digital now, but they still stick with microfilm as the standard. there are actually public records laws written around microfilm reformatting and retention schedules--it's going to remain a tool in preservation for a long time. forget sheet films, fiber prints and all that other good stuff. it's all about microfilm when it comes to preservation.

[kthompson]

well, you can read some of those links above, or read more of wilhelm's book that you all seem to have a problem with..or you can get online and check out CoOL, or delve into the almost 20 yrs worth of Consdistlist archives. Or you can go to one of those IPI conferences like I did--they usually last about a week and cost quite a bit, but they're chock loaded with archival management topics and then you can ask the IPI or whoever is there from NARA about silverlock. I noted in this chapter you all linked to--that Wilhelm mentions how NARA was going to being adopting the IPI polysulfide treatment for b/w film. The guy he mentions in that chapter was at the conference I attended as a speaker, but that was about ten years ago. You can see if anyone from NARA can field the quiestion as to whether they began using polysulfide toners on their film and how it differed from selenium in tests, and what it looks like now. My guess is nobody will know until we're all dead. Which is a moot point for us, but pretty important to the goals of these institutions.

thats' it for me. I just take it on face value that these guys are experts in their fields. perhaps you know otherwise.

[paulr]

When it comes to my own film, I don't tone it in anything, and I put in those mylar sleeves than Ken (probably justifiably) is suspicious of . Why? Because I'm not going to be around in 200 years to print them, and I don't care about them as historical documents. Any archival worrying is aimed at my prints, which for reasons of hubris I hope will last a while.

I only raised the point about not trusting selenium because someone brought it up as a reason to tone film. If you're interested in any kind of toning for preservation, I think it makes sense to look at what the research has revealed. The scientific evidence I've seen, however good or bad, has not supported selenium's usefulness. The only support I've seen has been annecdotal, "common sense" or from the home laboratories of guys like Ctein, who don't have the best track records when it comes to devising sound experiments.

It matters little to me who you choose to believe ... and as Kthompson pointed out, we'll all be long dead before anyone knows for sure. I'm just suggesting that if this matters to you, it might be worth questioning what's been prevailing as common sense.

[Oren Grad]

or from the home laboratories of guys like Ctein, who don't have the best track records when it comes to devising sound experiments

Paul, I happen to have visited Ctein during the time he was running the experiment that became the foundation for his published report on RC paper. I saw his experimental setup, which was well-conceived and well-controlled, and his results, which were convincing with respect to the specific, carefully qualified conclusions he drew from them. I'm sorry, but your generalization about his experimental skills is simply unwarranted. And it is very clear that selenium toning - or at least toning with the specific product Ctein used in his tests at the time - does have a protective effect that at least under some real-world circumstances suppresses at least one important mode of print deterioration peculiar to RC papers.

That doesn't prove how long those benefits will last for an RC print, nor that the effect is entirely due to selenium per se, or that selenium toning will have comparably dramatic benefits for FB papers, or negatives, of course. The bigger problem here is precisely the extrapolation of evidence from one experimental system to make sweeping claims about the properties of other systems that are analogous in some respects but not others.

Wilhelm's tests pretty much unravelled the idea that selenium does much for print longevity.

I'd appreciate a reference that supports that claim. There's nothing in "The Permanence and Care of Color Photographs" that has any such implication, and he is quoted as recently as the Jan-Feb 2005 issue of Photo Techniques as saying that "the fiber-base black-and-white print, when reasonably well processed and washed - and especially if it's selenium toned - can be considered the high water mark of photography in terms of permanence". This is a statement that excludes specialized processes such as Pt/Pd, but it's hard to avoid the conclusion that at least as far as silver printing is concerned, he thinks selenium toning has some value in this respect.

I don't really know whether selenium toning of FB prints, or of negatives made with general-purpose photographic films, has a meaningful protective effect under the real-world conditions my prints and negatives are likely to see. The caveat to take vendors' claims with a grain of salt is always warranted, especially when the evidence supporting the claim is not provided for critical evaluation. But no evidence has been provided here to support strong claims that there is no practical benefit.

[Brian Ellis]

Michael - You're partially correct, I shouldn't have said that the shadows "and midtones" are unchanged by selenium toning of a negative. The statement is correct with respect to the shadows, they are in fact unchanged (or if there is a change it's so slight as to be iimperceptible) but the midtone densities will increase slightly as you point out.

[paulr]

I started a new thread on toning here: http://www.largeformatphotography.info/lfforum/topic/502270.html

The information that I found was valuable enough that I wanted everyone to be able to find it.

One thing I'd like to clear up: I was mistaken in attributing my conclusions to Wilhelm's publications. I was remembering a paper someone had forwarded to me several years ago, and for some reason thought it was from Wilhelm. I'm sorry for the confusion.

Wilhelm's book supports using Selenium for print permanence, but this conclusion is not based on any of his own tests. They're based on the same sources everyone else has been using: tradition, kodak publications, and common sense.

The information in the new thread does not support these conclusions.

However, in the context of this thread, selenium toning the crap out of a negative, with the goal of maximum intensification, may well offer strong protection against many kinds of oxidation--since it has a fighting chance of converting all the silver to silver selenide. Partial toning offers very little protection.

But please read the full post if you're interested--I have not seen this information published anywhere else.

[paulr]

"Albiet a minor inconsequential one. :)"

We're ALL gonna die!

[Oren Grad]

We're ALL gonna die!

But with a judicious choice of toner, at least you can be well preserved...

[Bruce E. Rathbun]

So much information. After the intital post I was out of touch for a few days. This post has grown with so much with vaulable information. My original question was realted to a slight increase in contrast. Jorge is correct. My intent is to start printing pt/pd. My current method is printing on Azo. The past few years I have been exposing about 1.5 stops extra...i.e. my Zone IV is exposed as a Zone V. With an average 4" exposure I double for reciprocity and add another 50 %. Then I develop by inspection and push the highlights as far as possible. So in general I can produce an print on Azo grade 3 with some amount of burning on the highlights. My concern is that some negatives may reqiure a tad extra density for pt/pd printing. Overall my negatives have an increased amount of density so I should be okay. Once I start printing I will know for sure yet I wanted to do some intial research. I have known for years there were claims that Selenium toning adds stability to a negative. Thanks again to all who posted.

-Bruce