----- Original Message ----- From: "Robert M" <written_by@xxxxxxx> To: "List for Photo/Imaging Educators - Professionals - Students" <photoforum@xxxxxxxxxxxxxxxxxxxxxx> Sent: Sunday, June 12, 2005 6:23 Subject: Re: darkroom chemicals : None of your references comes from Kodak. A fine point, but quite important : in my view. Lets look at your references: no you're right, it IS important.. and I am still dredging thu my references to find the specific site link .. : The Alt list is not a reference worth trusting a hundred percent of the : time, no list is. and here you and I can agree 100% ;-) It was hardly a good starting point.. : > http://www.clir.org/pubs/reports/dirsci/dirsci.html : One reference discussed microfilm and selenium. Apparently, the link above : references ongoing research and not hard data. I will admit, I did not read : it all. To lazy, I suppose. Or, perhaps the reason is this: that page was : written in 1990 and therefore, it is (probably) out of date. That causes a : problem because much can be learned in five years. the publications are available but I am too tight fisted to spend the $ to buy their concluded articles, preferring to look for reputable references to them - the institute has apparently finalised a fair few studies .. in refence to one, this site http://palimpsest.stanford.edu/byorg/abbey/an/an12/an12-5/an12-507.html suggests the IPI concludes: "Geld (sic) 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." I have talked to conservators clearly without a clue and/or any deep : knowledge about their freaking job. Hahahahaha! You too!? :-) I had one guy urging people *SO STRONGLY* to wash, wash wash their prints for hours.. the results were that all who took this advice produced the ugliest, flattest prints with all the whiteners washed out and what looked like most of the silver too! : Sorry to break it to you, but some lists are started by people with very : little knowledge about the topic the list pertains to. nono, that's not news to me - I've been wrestling with such things for quite a time now too. Someone told : me iron was never used to make toners because it will not work. WRONG. That : Kodak never offered as many papers as I discussed. Wrong; Kodak offered : hundreds of papers, grades 0-6 (in some cases) and dozens of surfaces not : offered today. ah, the old 'there's no such thing, never was never will be' argument - quite funny when you're standing there holding a box of the product in your hand! No iron toners?? eeek! : The "Image Permanence Institute" entry discusses microfilm, not conventional : film and papers. here I'll suggest that microfilm is silver emuslions on the same film bases we photog's use, allbeit microfine grain, and also that their concern for image stability is of possibly more significance than ours (!) : Forget toning and GPS for a moment. If the film is properly processed, it : will last. Examples in my collection absolutely prove this and there can be : no debate. Yes, storage can make a difference, but these days, far too many : people point to dubious "proof" that is more often than not, a matter of : guessing rather than actual hard supporting data. For all I know, these : curious tests were not properly done. true. I have heard so much said and written about 'poor processing practices' of the past, when any look at a 40's photo technique book will clearly outline some of the tricks used by photographers to ensure repeat sales or how to prevent those customers given proof albums from keeping the proofs without paying for propper prints - printing out paper was one, another was to not fix the prints, another was to leave the prints saturated with fix. I imagine without an adequate and specific history of each photographer and each print, researchers drawing conclusions about print longevity from a collection of fading prints will not yeild a great deal of usable information. Likewise the old FB Vs RC paper debate. My tests, destructive as they were, showed that under adverse conditions, B&W RC papers *far* outlasted FB. The books still continue to say that RC papers haven't been with us all that long (how long has it been now?) and they point to existing FB prints from way back as proof that FB is superior. personally I use both, selected for the surface texture more than anything else. Silverfish don't like RC paper much, slugs can be encouraged to eat it though, but they have to be starved for a while first! : Again, where does it specifically say, in Kodak's words, these toners and : protectants do not work? I just took a look on Kodak's web site and they : specifically recommend the use of Rapid Selenium Toner for Archival : Processing. They recommend: "Dilute 1:20 for print protection and 1:20 or : 1:40 to increase shadow contrast and maximum density with a minimum tone : change." The same page mentions gold solutions; several in fact. still looking (between typing this ;-) <cliped vaild points> :Test : results also indicate that dry-mounted prints, no matter what board they are : mounted on, fare better than prints that are hinged or corner-mounted. The : dry mount tissue serves as a barrier to pollutants that have been absorbed : by the mount board." : : : Our collection was stored in hundreds of liquor boxes; the plates and : negatives were stored individually in Kraft paper envelopes, 11x14/16x20 : plates on shelves. Apparently this is a "bad idea," because it causes : "problems" Sorry, my experience was this was not a big issue and the fact : tat some of the images were produced in in the 1800s, show the storage : materials and storage conditions are important, but not a guarantee that : disaster will happen. Youre seeing the same as I - stated, popular *facts* that are unsupported by evidence. : Why did they last? Well, we did things correctly. Proper chemical mixing, : attention paid to exhaustion, stop bath, two fix baths, proper washing, and : the use of hypo eliminators. Since the 1800s, and no evidence of : degradation, spots, funky tones, or smells. I've heard stories about water colour images being of very poor longevity, but very old watercolours still turn up, carefully folded between the pages of books that show little discernable degredation. Storage is what archiving and preserving is all about. Anything can be preserved stored correctly - fish intestines, fungi, anything - the appropriate archiving method is what's needed to ensure they survive. : 100% rag board is mentioned but not discussed much. Except that it is a bad : idea and as the comment stands, silly to be sure. What kind of 100% rag are : we (they) talking about? I have many items printed on 100% rag and they : suffer few problems. Our currency is 100% rag and it is exposed to many : strange conditions. Still holds up. I have cheap stamped envelopes going : back many decades, and still in perfect condition. It is quite likely these : envelopes are 100% rag. I have some "dime novels" still in pristine : condition, but printed on cheap paper pulp. huh, rag's no good?? Much of the old rag seems to be hemp or linen in origin.. I wonder if the reviewer was buying something *labelled* rag that was not in fact rag at all.. : Furthermore, I have many images mounted on poor quality materials like : pressed pulp and Masonite. Again, no problems. So what do I believe? My : large collection of solid evidence or someone's "proof" the images will not : last? yourself and your own experience ;-) : I am all for testing. However, and no offence, but how are you testing? How : are your students testing? Specifics please. "My fixing is adequate" OK student number 1, apply a drop of sulphide solution on the paper and see if it changes.. Oh looky there.. now go back and fix properly. "My washing is adequate" OK student number 2, apply a residual fix test.. grab the silver nitrate and acetic acid solution. Place a drop on the edge of your print, flush with a salt water solution after 2 minutes. Anything more than a light yellow stain indicates residual fix "Mine's washed well" yup, the test shows there's no fix left, now lets stick it under karl's Patented UV Densitometric Whitener Analyser and, whooah! you've washed this for HOW LONG??!! "My fix is not exhausted" or "my fix time is adequate" Lets fog a piece of paper then drop it in the fix for as long as you'd normally fix then wash it well, then drop it in the dev and give it the usual dev time - now see that lovely dark grey colour - that means ALL your prints will probably darken to that colour in time. "Citic acid is FINE as a stop bath" lets just grab some gear and do a titratrion, after pouring two fix/stop bath combos and allowing them an hour to react/not react.. now see all that sulphur that's precipitated? Yup, you've just killed half of your fix by carrying x amount of citric acid into the fix. Now the goodies. Sepia tone, Selenium tone, Gold tone some prints. Now lets bichromate, ferricyanate and iodide bleach them - oh, the sepia toned image wouldn't bleach.. note that folks. Now lets pour nasty oxidising agents across the images - etc etc.. The course was an advanced diploma of science, not arts, and we trained chemists, doctors, pharmacists, forensic cops and the like - there was an artsy component but they were never allowed access to the electron microscopes or gas chromatographs. Those both are gone now as the course has been dumbed down :-( :You are probably not setup to : properly test these issues; your students are most certainly not. I was once : a teacher at the SLC Art Center ("Art Barn," Finch Lane, Utah) so I know : students will often parrot what they are told by their instructors. ooh yeah! hence my attempt to instill in them the philosophy that they should read eaverything, listen to everything and believe nothing until they were able to support the evidence themselves - just as I was tought when studying chemistry. Lecturer would blither on about some facet of organic chemistry, the next lab session ould be to test and reproduce the results. I did those sorts of sciences, where you HAD to conduct repetitious experiments to support or disprve stuff, not just observe and conclude or parrot what you'd been taught. : Last month I was told my statements about polarizers were wrong. I said : solid glass polarizers are not available; all filters available to : photographers are film sandwiched between glass. well you're right.. I missed that one, I can't see how anyone could argue that! : Again, no offence, but, if you lecturing, why tell your students not to : believe your words? I am guiding them to finding or producing results, not spoon feeding them *facts* I had this happen to me at school and even as a kid, found much nonsense in what was being taught. I say a 50mm lens has a fov of X angle? no, I say lets work out the FOV, how will we do that? Lets grab the optical bench, a target and a few other odds and sodds and next thing you know these folks *know* what the angle is - better than having to remember some idiot fact ... and they know *why* something is so :-) I feel good . : We live in a world where much of our knowledge is available with a simple : Google search. Unfortunately, we have access to an equal amount of incorrect : information, as well. Then it spreads. God help us all. hell yeah - I concur. (damn, still can't find that ref!) : For all I know, you are correct and Kodak did say what you say they said. : So I am asking for a legitimate link to an exact quote from Kodak, not a web : site or mailing list. Back up your words and offer me a few crumbs. Until : you do, I will refuse to believe you. Sorry about that (Smiley+) hahaha :-) I'm getting back to you with that ref soon (hope) There are too many myths out there, too many observers who know little about scientific method and aren't fussed about writing whatever they've seen. Some sciences cannot and do not work in a scientific way, they are merely supported by other sciences. oops, I was going to cite another example and repeat my fault (which I confess!) of not providing adequate references.. let me find a book before I do that. Re the gold toning or even selenium for that matter, I confess to having swallowed the accepted theory for quite some time, but when the alternative was put in front of me, my chemistry training kicked in. There are a few ways to protect metal - the one in which we are concerned with is plating. now none of the metals used are sacrificial in any way (good), and neither are they likely to cause the silver to become sacrificial (gooder! ;-) so then what have we really got? - A coating, much like putting on a coat of paint. In the same way, it does not work interactively with the metal being protected but rather works as a barrier. The chemical process involved to get that coating on is not electroplating so we are not assured that the coating will be as uniform as electroplating, and neither can it be as thick. Chemical plating occurs when a complex is formed which allows the gold/palladium/platinum salt or whatever to form the chosen metal to the outside of the silver. In an emulsion there is NO way that we can assure uniform coating, so it's safe(r) to assume the coasting is faulty. this is a very valid assumption but can be disputed as being at the heart of the discussion. (still lookin'!) What of sulphide toning though - the chemical process is to use an oxygen group element (S) to react with the silver salt produce silver sulphide. This is a stable chemical that requires a repeated attack by a coplex ion to allow it to react, so we're pretty safe with this salt which is dark coloured (so we can see it on the print). the sulphurous component is not readily oxidised unless you subject it to high temperatures (read as burn the print!) so all in all, it's a very good method of preserving the image. Selenium toner - Selenium is an oxygen group element too, like sulphur but it's less reactive and has a lower reduction potential than sulphur, but higher than oxygen (sulphur has oxidation numbers of -2, 0, +2, +4 and +6) - it tends to act more like the arsenic group than sulpur. Sulpur is very reactive.. especially with elements of lower reactivity it acts as an oxidising agent and forms sulphides - this reaction can be vigorous with some metals, especially if the metal is finely divided ..like photographic silver :-). oh - here's one ref worth going through by Douglas W. Nishimura, Image Permanence Institute, RIT: http://www.largeformatphotography.info/toning-permanence.html ..just thought it worth responding with *something* until I locate that letter from Kodak. k
