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Formule per chimici fotografici fai da te

PYROCAT-HD

Pyrocat-HD is a pyrocatechinphienidone based developer formula that I developed about ficw years ago for rotary processing of sheet film in tubes and drums In this application it has some clear advantages over pyrogallol based developers like ABC Pyro PMK Rollo Pyro and WD2D because it is less likely to cause stains and uneven development However a lot of photographers have found that Pyrocat- HD works well with tray processing as well and I know of quite a few who are using it with development by inspection which is the primary reason I joined in this discussion on the AZO forum I am happy to post the formula here and folks shold know that other than the formula at wwwunblinkingeyecom this is the only one I authorize andor have checked for accuracy I say this because I have seen errors in the formula at other sites I would add that Pyrocat is sold as a kit by Photographer180s Formulary but I have no control over its production and can not vouch to the accuracy of the formula Basically Pyrocat-HD is mixed as two stock solutions that are diluted to make a working solution for developing I recommend the 1:1:100 solution for silver printing 2:2:100 for alternative printing and for soft grades of AZO [Prosegue]

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SVILUPPO PER CARTE ALLA VITAMINA C

 6,8 grammi di sodio idrossido 24,4 grammi di borace 8 grammi di acido ascorbico 0,8 grammi di metolo (oppure 0,082 grammi di fenidone) 1 grammo di potassio bromuro (per 0,082g di fenidone = sciogli 0,82 grammi di fenidone in 100 cc di alcool etilico) miscelate il tutto in un litr... [Prosegue]

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ACID ASCORBIC FORMULAS (BY PATRICK GAINER)

Non-chromogenic Antiscorbutic Developers for Black-and-White by Patrick Gainer This article180s title is my slightly humorous way of saying that I have concocted some developers for black-and-white film that contain ascorbic acid You may recall that ascorbic acid is commonly called quotVitamin Cquot The Lesser Advantages Being more than 65 years old has some compensations even some joys For example I learned that prune juice bottles make fine wide-mouth containers for developer Every once in a while just when I think I know all there is to know I learn something that I didn180t know before As often as not what I learn is that something I thought to be true is not When it is something that a lot of other people also thought to be true then I think I have made a Great Discovery Others make these Great Discoveries also upon occasion For example once upon a time everyone knew that the tomato was deadly poison and that one could demagnetize a permanent magnet by rubbing garlic on it I didn180t discover the fallacies in those beliefs but whoever did made some Great Discoveries Now we can have pizza with tomato sauce and we don180t have to worry about getting garlic on our refrigerator magnets An even greater advantage of being over 65 is that people think it is normal when you wander off the subject Untitled print by Patrick Gainer 35mm Arista 125 film developed in borax-metol-c developer Printed on Seagull Select VC paper with no filtration developed in carbonate-metol-c developer Those Greater Advantages For manv years I have mixed developers from scratch both for practical reasons and creative ones My formulas were usually other people180s formulas although I did some experimenting I read what I could find both on that particular formula and on the theory of developers Most of my experiments were based on the usual rules: a developer needs beside the quotdeveloping agentquot a preservative an accelerator and sometimes a restrainer Developing agents most readily available were metol hydroquinone and Phenidone The preservative was a sulfite usually of sodium which sometimes served also as accelerator If more alkalinity was needed then borax sodium metaborate sodium carbonate or even lye were used Some of my experiments were described in the article quotKitchen Tested Soupsquot published in the April 1973 issue of Petersen180s Photograpbic The principal purpose of that article was to show that volumetric measurements of solid photographic chemicals were quite satisfactory for most purposes Upon reading that article probably believing it to be an April Fool180s joke a friend went out and spent much money on a balance for weighing his chemicals to the milligram I retired after 30 years of employment by NACA-NASA as an Aeronautical Research Scientist and am now living in wild and wonderful West Virginia 50 miles from the nearest retail source of photographic supplies It takes from 7 to 14 days for shipments to arrive by UPS For others in my predicament it might be reassuring to know that a few grams of Phenidone are a lifetime supply and that the other ingredients of a very good developer for black-and-white film and paper can be obtained at a health food store and a supermarket Anyone who prepares developers from quotscratchquot knows that sodium sulfite and sodium carbonate are the most expensive ingredients In a gallon of D-76 for example the metol may cost about 65 cents but the sulfate can cost as much as 450 Not only that but carbonate and sulfite are the chemicals you run out of most often For many years I used the washing soda form of sodium carbonate because it was cheap and readily available The last I got was so heavily perfumed I couldn180t stand to have it in my print developer In any case none of the local stores have stocked it lately What About the Sulfite I found several ways around my odoriferous carbonate problem but what could I do about the sulfite When my sulfate began to run low and I noticed that my wife hid purchased some ascorbic acid crystals from the local health food store I remembered that ascorbic acid is used to keep canned and frozen fruit from oxidation-related discoloration Also I had read many years ago something about 1-ascorbic acid forming a superadditive pair with metol At the time 1 thought that 1-ascorbic acid was not the Vitamin C form Later I learned that onlv 1-ascorbic acid has antiscorbutic properties So I decided to experiment What I learned I wish I had known 25 years ago After some considerable application of the scientific method--trial-and-error--I arrived at several sulfite-free developers for black-and-white materials some with metol and others with Phenidone If you do not have a balance you can still use these developers because I will give quantities in volumetric as well as weight units If you are interested in purchasing a balance I can recommend one made by Lyman for weighing gunpowder and bullets It is available in two forms at sporting goods stores--one calibrated in grains and the other in grams It weighs accurately up to 500 grains and should cost about 35 The Final Side-track Before I describe my experiments I should tell you of my alternate sources of sodium carbonate First any department or hardware store that sells swimming pool supplies will probably sell quotPH PLUSquot a trade name of the Olin Company The label says it is 98 sodium carbonate and it seems to be anhydrous because intense heating caused no loss of weight It works and it costs 15 of what you get from other sources I have no idea what the other 2 is except that it is claimed to be inert A second substitute is as follows Any brand of baking soda is very pure sodiwn bicarbonate Red Devil brand of lye is very pure sodium hydroxide If you mix one weight unit of lye with 21 weight units of baking soda in water you will make a solution of very pure sodium carbonate The chemical reaction is shown below: NAOH + NaHCO3 --gt 4Na2CO3 + H20 The resulting solution is exactly the same as if vou had used 31 weight units of monohydrated sodium carbonate Lye is best handled in solution because of its propensity for picking up water and C02 from the air while you try to weigh it The contents of one full 12-ounce (340 gram) can of lye dissolved in water to make 115 fluid ounces (34 liters) make a 10 solution which you can further dilute to suit your fancy Start with very cold water use a vessel that can stand some heat and add the lye slowly to the water You can make a convenient 20 solution of sodium carbonate monohydrate by combining 645 g of lye (645ml of 10 solution) and 1355 g of baking soda in water to make one liter If your tap water is as hard as my well water use distilled water or rain water A third method of getting sodium carbonate locally wherever you may be is to heat baking soda The temperature required is quite high I used a stainless steel saucepan on the stove top When the baking soda is hot enough you will see little geysers of steam and carbon dioxide which are fun to watch but which spray powder around I convinced my wife that the white coating on the stove was an excellent degreasing agent but I still had to clean it up Anyway it is not good to inhale the powder so put a lid on the pot When you agitate the contents with a swirling motion it will feel as if there were liquid in the pan until all the gases have been given off A pound of baking soda yields 106 ounces of anhydrous sodium carbonate which is equivalent to 124 ounces of monohydrated sodium carbonate One tablespoon of this anhydrous carbonate weighs about 88 g One more thing before I proceed Developers requiring Phenidone have such small amounts that it is convenient to make a solution of Phenidone in alcohol You may use either denatured alcohol from the hardware store or 91 isopropyl rubbing alcohol from the drugstore Don180t use the 70 stuff Dissolve 14 teaspoon (065 g or 10 grains) of Phenidone in alcohol to make 80 ml The Phenidone keeps quite well this way which is a good thing as the 80 ml will make 8 gallons of film developer The Evolution of My Film Developers I don180t remember what my first trial was I do remember that I learned very quickly that anything like the usual concentrations of developing agents would be much too vigorous for practical use I settled on 5g of anhydrous sodium carbonate 2 g of ascorbic acid and either 02 g of metol or 25 ml of Phenidone-alcohol solution to make a quart of developer Either of these formulas is about as active as full-strength D-76 For example I would give Tri-X 8 minutes at 68176F for normal scenes to be printed with a diffusion enlarger Both formulas worked quite well on all the films I could get my hands on including Ilford HP5-Plus and Delta 400 Kodak Tri-X Plus-X TMax 100 T-Max 400 and T-Max 3200 and Arista Pro 400 and 125 The sharpness is excellent and the grain is surprisingly fine What is the chance that I got a special batch of ascorbic acid crystals I tried other forms of Vitamin C in capsules and in tablets What I learned is that tablets are hard as heck to dissolve and I had to crush them to do any good Furthermore there was still some insoluble flotsam and jetsam that you might want to filter out but the solution worked Capsules would be convenient because they contain measured amounts and they can be taken apart to get out the acid but even though it is powdered there was still some residue to be filtered Ascorbic acid crystals obtained from General Nutrition Centers (a national chain) will have 3 obtained from rose hips have a slightly pink color and may leave some residue but work as well The purest I have found is distributed by NOW Foods (Glendale Heights IL 60139) It is also the least expensive in mv area at 995 for a half pound Can the Ascorbic Acid be Replaced What is going on here Is the ascorbic acid merely a preservative Could it be replaced by sodium sulfite No I tried Given the same development time the same concentrations of metol or Phenidone and the same amount of carbonate but substituting 2g of sulfite for the ascorbic acid produced such a faint image as to be almost invisible A little study of what might be the products of reactions in the developer solution excluding the development itself turns up some interesting facts While it would seem that the base in these experiments is sodium carbonate that is not exactlv the case If there is more sodium carbonate than is required to convert the ascorbic acid to sodium ascorbate the following equivalence holds: xNaC03 + C6H806 C6H7NaO6 + NaHCO3 + (x-1) Na2CO3 (Where C6H806 is ascorbic acid C6H7NaO6 is sodium ascorbate and x is an undefined variable) The arrow goes both ways because there is no effervescence or precipitation On the other hand if there is an excess of ascorbic acid then the following holds true: NA2CO3 + 2C6H806 --gt 2C6H-NaO6 + H20 + C02 In this case you get a lot of effervescence that continues as you add carbonate until all the acid is converted to sodium ascorbate or all the carbonate has been added It makes a difference then which you dissolve first In the first case the result is equivalent to sodium ascorbate added to a buffer solution of sodium carbonate-sodium bicarbonate and the pH is less than in the second case If you base all quantities on 2 g of ascorbic acid then 1204 g of monohydrated sodium carbonate plus 2 g of ascorbic acid are exactly equivalent to 2239 g of sodium ascorbate plus 0954 g of sodium bicarbonate provided that you dissolve the carbonate first The recipe that I arrived at by trial-and-error has about 38 g excess carbonate Together with the bicarbonate it forms a pH buffer Remember that 1 unit of sodium hydroxide plus 21 units of sodium bicarbonate are equivalent to 31 units of sodium carbonate monohydrate (or 265 units of anhydrous sodium carbonate) The 38 g excess carbonate are equivalent to 3Ol g of bicarbonate + 143 g of sodium hydroxide With that in mind I did a little research and found in the Handbook of Chemistry and Physics tables for two buffer pairs that seemed appropriate: sodium bicarbonate-sodium hydroxide and borax-sodium hydroxide If the carbonate is dissolved first the excess sodium carbonate in my original recipe along with the sodium bicarbonate formed in the conversion of ascorbic acid to sodium ascorbate are equivalent to 396g of bicarbonate plus 143 g of hydroxide This ratio corresponds to the ratio in a standard buffer solution of pH approximately 108 but the concentrations are somewhat greater than standard If the acid is dissolved first the bicarbonate is down to 3-01 and that ratio corresponds to pH 115 or greater Sodium ascorbate does not contribute much to pH as even a 10 solution has pH between 74 and 77 Out of curiosity I decided to see what would happen if I used a standard buffer solution of pH=108 (as nearly as I could make it) the base for my developer According to my calculations the developer would then have 281 g of bicarbonate 11 g of hydroxide and 225 g of sodium ascorbate per quart in addition to the developing agent If I use 2 g of ascorbic acid in place of the ascorbate I require 0454 g more of the hydroxide for a total of 155 This formula works as well as my original Dissolve the bicarbonate and the lye before the ascorbic acid The pH value of 108 is within the range of a standard borax-sodium hydroxide buffer solution 61 g of borax (20 Mule Team is just fine) plus either 17 g of hydroxide and 2 g of ascorbic acid or 125 g of hydroxide and 225 g of sodium ascorbate plus the developing agent make a quart of developer that is as active as the carbonate version It has the advantage that it does not produce gas bubbles in acid stop bath Pure sodium ascorbate as an alternate form of Vitamin C for those who cannot tolerate the acidity of ascorbic acid is obtainable from NOW Foods I have tested it and found that the aforementioned equivalences are true Developers for Paper Everyone knows that hydroquinone developers are slow unless the pH is so high you can180t put your finger in the solution However without sulfite hydroquinone is quite active even at moderate alkalinity at least for a little while It seems that the sulfite while preserving also inhibits Can we keep this activity and prolong it by using ascorbic acid in place of sulfite November by Patrick Gainer - 4x5 HP-5+ Print developed in Metol-Ascorbic Acid developer Print developed in Hydroquinone-Ascorbic Acid-Carbonate developer Note warmer tone and different gradation Mix 1 tsp (about 3 g) hydroquinone 12 teaspoon ascorbic acid crystals and 1 tablespoon of sodium carbonate (about 15 g) in a quart of water Use it as a print developer Be prepared for strange results Development takes a while to start then accelerates The result looks like some kind of solarization I believe what has happened is called quotinfectious developmentquot a characteristic of some process developers but it has been so long since I read about it I can180t be sure If so it is one kind of infection that Vitamin C can180t cure But add 2 ml of Phenidone-alcohol solution and try again Now you have a fairly decent print developer Do not mix any more than you can use in a couple of hours if you decide that it is worth using at all Actually the hydroquinone is not needed You can get all the density range your paper can give with metol or Phenidone ascorbic acid sodium carbonate and a little bromide Use 1 tsp (4 g) of ascorbic acid 1 tablespoon (15 g) of PH-Plus and either 18 tsp of metol or 5 ml of the Phenidone solution to make a quart of developer Add bromide to suit I use 5 drops of saturate solution The recipe for paper is almost a double-strength version of my film developer In fact if you make a developer stock solution just like the film developer but four times more concentrated vou can dilute it 1+3 for film and 1+1 for paper Even the borax formula Conclusions My recipes are summarized in the accompanying Table I and Table II You may draw your own conclusions but I am quite convinced that ordinary ascorbic acid obtainable as Vitamin C has valuable photographic uses It makes possible sulfite-free developers with very low concentrations of the customary developing agents It is certainly economical enough and the major constituents are no strain on the environment I have included several photographs the negatives for which were developed in one or another of my formulas Some of the prints were made on ORWO 111 grade 2 sold by Freestyle as quotGermany180s Finestquot Others were made on Seagull Select variable contrast fiber base paper I have done some but not much sensitometric analysis My equipment for the purpose is verv limited I used a cardboard box painted flat black inside with a hole in one side This hole is about as near a black hole as you may see on earth I cut a Kodak gray scale in half and mounted one half on either side of the black hole Photographic negatives of the gray scale were projected by my C-760 dichroic enlarger and the projection densities were read using a homemade (and designed) photometer calibrated in logarithmic units You can see the results in Figure 1 The densities in the plots are those the paper would see if I had made prints They include the effects of flare in the camera lens and body (Canon AE-1 85mm Canon FD lens) and other experimental artifacts [Prosegue]

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LUKACS TWO BATH FOR TECH PAN

 Usable EI of 32. 1. Pour in prepared solution A. Agitate continuously for 3 to 3.5 min. Pour out solution A. 2. Pour in solution B immediately after pouring out A. Agitate continuously for 3 more min. Discard solution B. 3. Pour in water or water wash for two minutes. ... [Prosegue]

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POTA DEVELOPER

 Sodium Sulfite 30 grams 1-Phenyl-3-pyrozolidone 1.5 grams (Ilford Phenidone-A, or Kodak BD-84) Water to make 1 liter Dissolve the chemicals in water at about 100F (38C), then cool to working temperature and use immediately, since the so... [Prosegue]

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