Alan Marcus

The powder should be OK if it is not black. Mix some up and test in the light by swishing a short piece (tongue) in the fluid. Film should change from milk to black quire fast. If it does this then its OK. A home photo lab can't dump much toxic stuff -- Siver is considered by the municipality to be the bad boy, actually its oxygen demand.. Fixer causes chlorine to effervesce out of solution. This is the same stuff used by tropical fish hobbies to rid their aquariums of chlorine. Fixer, in quantities will cause the chlorine to go out of solution at the local treatment plant. Ups their cost of operation but a home photo lab dumps too little fixer to make a difference.

The silver in solution combines with the sulfur in the fix to form inert silver sulfide.

First -- No need to make a special trip to a disposal site! If you are not on sceptic tank (rural area), then OK to feed them to the sewer system. The main thing a sewer system wants to avoid is silver in your effluent. While spent photo waste does contain some silver, unused photo chemical are void of silver. Some forms of silver are toxic. Photolabile waste does contain but photo waste quickly combines with sulfur from the fixer and this renders the silver inert. The real concern is BOD and COD. Biological and Chemical Oxygen Demand. In other words, photo effluent takes on oxygen as it travels down the sewer to the waste treatment plant. Your tiny oxygen demand will be just a thimble worth. Don't worry its OK to dump, Big photo labs must pre-treat to knock down the oxygen demand. As to the Selenium, test on a small quantity of photo paper. It will work or not. If not, then replace. Ran 7 giant photolabs each 20,000 rolls a day. Was well schooled on photo waste handling. Also, if you feel better about it, take your photo chemical to a disposal site.

It was a light spray of color developer. The image was than scanned using white light and IR. The image was digitally reconstructed, This was a giant black and white film camera used for railway photography the year was 1900.

The camera was loaded with color negative film. This negative was printed on Kodak TransLight. A color paper emulsion coated on a film base with one side coated with a white translucent material. The TransLight was used in back lit displays. Often used in the lobby of motion picture houses to advertise future attractions. They were beautiful - breathtaking. They were made by projection using a color enlarger.

It’s actually incredibly easy to develop film! We have been at this for nearly 200 years. Of all the film, sheet film is the easiest because the sheet size is quite small, and thus easy to handle. Exceptions are giant film sizes used to display. Kodak displayed a giant 18 by 60 foot “Colorama” at Grand Central Station New York for more than 40 years. Us “grayhairs” developed sheet film in trays just as we did sheets of print paper. We plopped them into a tray of developer, adding additional sheets -- sometimes as many as 12 at a time. We shuffled its stack, moving the top sheet to the bottom; this was how we agitated. My darkroom had large tanks made of “hard rubber”. These accommodated 8x10 inch sheet sizes inserted in a stainless steel metal rack. Various rack sizes were common. I had racks that held four 4x5 inch sheets and racks that held 2 ¼ x 3 ¼ sheets. For agitation, nitrogen gas was piped into the tank. This inert gas created bubbles in busts every 15 seconds. Despite how incredibly easy it is to develop film, there are perils. The developing process requires that the developer infuse into the film emulsion at a specific rate. Anything that interferes causes blemishes. Improper handling, like fingerprints on the film, is a no-no. Oil from the fingers slows the infusion rate; this leaves permanent blemishes. The Polaroid process used a gelled developer. It was contained in a pod that was ruptured by rollers as the film was transported in the camera. These rollers spread this reagent uniformly on the film to be developed. OK, your method might work! The point is why at this late date, at the sunset of chemical photography, try to reinvent the wheel? You might like to know, Kodak acquired Applied Science Fiction of Austin TX. They invented a method to atomize developer and spry it onto film. The year was 2003.

No need to use expensive swabs - a clean well washed "T" shirt will do this deed. Buy some film cleaner and apply to cloth and wipe off. Difficult dirt, start at the center and work outward with circular strokes.

John William Strutt, 3rd Baron Rayleigh, Astronomer Royal, Chancellor University Cambridge, Nobel Prize Physics 1904, observed that old lenses on the shelf pass more light than new one of the same designs. New ones reflect away about 4%, whereas old ones only 2%. Additionally, Harold Taylor, in 1892 also observed this phenomenon. Seems old lenses on the shelf were blemished with a coat of soot, bad air due to coal burning. Air pollution had deposited a thin transparent coat that somehow reduced surface reflections, thus allowing more light to transverse the lens. Taylor experimented and found a way to artificially bloom (age) lenses. This truly was an important discovery, because new lenses suffer a 4% loss in light due to reflections off their polished surfaces. Consider that a multi element lens array like a telescope or camera often suffers a light loss of 40 – 50%. Additionally, there are inner reflections as each element has two polished surfaces. This will induce a loss at each junction. Internal reflections induce stray light in the optical system. This is devastating as it greatly reduces image contrast and spawns glare spots and ghost images. Many coating methods are used. One method is to place the lens to be coated in a vacuum chamber. The air is evacuated, and the mineral that will be deposited is heated causing it to vaporize. This vapor condenses on the glass lens and coats and etches. It is the thickness of the coat plus the material that does the trick. It works best when it is ¼ wavelength high. The incoming light ray passes easily through the coat/air junction. It then hits the polished glass and 4% is reflected away. These reflected rays hit the coating air junction and about half of them are re-reflected backwards into the lens, boosting the number of photons that will traverse the lens. Because coat thickness is key, a coat is naturally optimized for a specific color. A modern lens has multiple coats applied. Each coat is different in thickness. A high-quality lens can have as many as 7 thru 11 coats. As time passes, coating technology advances. Likely each discovery will give small improvements. A tip of the hat to William Strutt and Harold Taylor.

These negative appear too dark (fogged) to me or perhaps over developed. A proper developer solution has an additive called a “restrainer” that mitigates chemical fog. Your negatives will print up OK provided the fog is uniform. As to the fix, you can easily test the fix. In the light, dip a snip of film in the fix and swish it about. The film enters the film opaque and after a few minutes, becomes milky and then transparent. Time this reaction (time to clear). The safe fix time is double the clear time. I can’t speak for this film but many 35mm films have a noticeably gray base tint. This tint is not present on wide roll counterpart films. This base tint is intentionally added to 35mm film to reduce light piping. Not seen on rolls with paper backing with its flat black backing. We are talking about unwanted exposure due to light transmission contained by the interfaces, base, emulsion, topcoat etc. This action is similar to the action of fiber optics. Light piping will fog film at the edges due to exposure to light during loading and unloading. Cine film often has an added carbon black back coat called a RemJet. This is removable jet black back coat of carbon held in place by cid plastic binder. During developing, Cine film is placed in a alkaline solution to soften the acid plastic thus allowing the RemJet to be easily buffed off with a soft cloth. Anyway, if you suspect the fixer solution, you can safely re-fix in the light. Generally, if the fixer is substandard, the film will be blotchy (not uniformly discolored).

The dyes are organic (organic chemistry). Organic things change their characteristics quite easily. The C-41 dyes are highly alterable if the pH is wrong. They revert back to a leuco state. The film is a subset of black & white, thus a silver-based image replaced by dye. The bleach step coverts metallic silver to a salt of silver. This salt is soluble in the fixer (may be a combined step). If silver is retained, it veils the dyes. This condition and dye reverted to leuco is reversible by repeating the bleach / fix steps.

The cyan, magenta, and yellow dye incorporated in C-41 film are in a “leuco” (Greek for white). They remain uncolored until they receive a missing ingredient which causes them to blossom. Hanson tinted the leuco magenta dye yellow and the leuco cyan dye magenta. This combination appears orange. As the leuco dye blossoms, the tint diminishes. The tints thus form two positive images superimposed atop the three negative images. This combination delivers a more faithful image. All dyes used are tweaked as technology evolves.

Good points -- perhaps a re-bleach and fix will correct

As you know, black & white film photography generates an image by chemically depositing a layer of metallic silver on film. This silver laydown is in proportion to scene brightness. The film thus displays varying translucency that controls how much light traverses the film at any given location. Color photography is a subset of this technology. The colors are obtained by replacing the silver with dye. Basically, three emulsions are layered, one sensitive to red, one to green, and one to blue light. These are black & white emulsion. They develop up as three separate silver images. A search was on, following World War II, to make sensible color films that are easy to process. The goal was a film that reproduces a faithful image. The answer, put colorless dye in each of the three emulsion layers. To get a colorless dye, it must be incomplete, and all three should be missing the same ingredient. If they gain this missing component, they blossom forming brilliant cyan, magenta, and yellow dyes. Such a strategy will greatly reduce the pool of suitable dyes. The Kodak E-6 (color slide film) and Kodak C-41 (color negative film) use the missing ingredient idea. They are called incorporated color film because the dyes are placed in the film at the factory. The developer is a black & white formula plus the missing ingredient. Basically, the film is placed in the developer. A three superimposed black & white silver image results. As the silver image evolves, the silver takes on oxygen that is dissolved in the waters of the developer. This silver oxide acts as a catalyst causing the missing ingredient to unite with the three dyes. A cyan dye image is thus overlaid atop the silver image in the red emulsion. A magenta dye image in the green emulsion. A yellow image in the blue emulsion. Now all three needed dyes are in place, however the image is veiled by the silver images. A bleach bath followed by a fix bath removes the silver images. The film emerges, the dyes have blossomed making a color film image. The image is not faithful. The need to find three dyes missing the same ingredient is responsible. A yellow dye should pass red and green light with little interference, and it should block blue light. This is what happens, the yellow dye is acceptable. The magenta dye should allow blue and red light to pass without restriction and stop the passage of green light. The magenta dye is lacking, it leaks some blue light. The cyan dye is meagre; it leaks lots of green light. In a slide film, we must live with this, but a negative film is just a means to an end, we don’t look at the negatives, we use this negative to make positive prints or slides etc. With negative films we can use clever ways to make improvements. It was Wesley Hanson of Kodak Labs who figured out how to make an improved color negative film. Hanson added a touch of yellow to the incomplete magenta dye and, a touch of magenta to the incomplete cyan dye. This molded the finished dyes making a film that yielded a more faithful image. The orange tint (mask) is counteracted by the printing process, The mask is composed of two positive images that are superimposed atop the three negative images. It improves the color and contrast of the finished negative. The mask is not uniform orange. It is a positive image, strong orange in the unexposed areas and feeble in areas of high density. The hue of this orange corrective mask used is based on the makeup of cyan, magenta, and yellow dyes uses when manufacturing the film. As new and improved dyes are discovered, the color of the orange mask must be adjusted as required. A tip of the hat to Hanson

Historically, the darkroom with the enlarger had shelfs and drawers filled with boxes of unexposed photo paper. We are talking, glossy, silk, pebbled, simi-gloss, singe weight, double weight and lots more. In addition, most of these textures were labeled based on its contrast. Grade 2 was “normal”, we are taking grade 0t through grade 6. What I am trying to tell you is, our paper inventory excessive. Variable contrast photo paper saved the day, One box or this magic stuff and contrast changing filters cut our inventory to a manageable level. These papers have two emulsion coats. One is sensitive to blue light and the other to green. One coat is high contrast and the other low contrast. With a little practice, we learned to pre-judge the negative and the resulting print it will make. We learned what contrast grade of paper was the best fit to produce an “optimum” print. The filters adjust the white light of the enlarger, changing the ratio of blue to green exposing light. This cleaver method allows a single box of paper to operate at every possible corrective contrast level. The yellow filter is a blue blocker, the magenta filter is a green blocker. These are in different strengths allowing the one box of paper to operate at every possible contrast level.

Photo chemicals are not contaminated! OK to use unless oxidized or exhausted. B&W film won't harm.

A tip of the hat from Alan Marcus

When I was 10 years old, photography and film developing, and printing was pure magic. I got one of these Kodak contract print box, photo paper plus hard-rubber trays and in the closet, did the deed. I became quite proficient and went on to do this stuff for my career. Built a reconnaissance lab for the US Air Force in Korea in the 1950’s. Built 7 giant regional labs for photofinishing, each sized to do 20,000 rolls of black and white and color film a day. Installed about 200 mini-labs in a drugstore chain. Hired by mini-lab manufacture, retired after more than 55 years in a successful and satisfying career. It all started with a simple contact printer that worked just fine.

A better edit of above (I am a terrible speller! Optically, I don’t think a good enlarger lens will produces a sharper image than a prime macro. Both are optimized to image a flat-to-flat. In other words, enlarger lenses are optimized to image a flat film and project it’s image on a flat light sensitive surface. Conversely, a macro is also optimized to image flat-to-flat. That being said, a macro has advantages. A macro that properly attaches to a camera will be electronically and mechanically coupled. Thus, the macro benefits as it is granted the benefits of the camera’s automation. When doing close-up work with lenses other than a macro, you will grapple with what we call “bellows factor”. Allow me to explain: The f-numbers engraved on the lens barrel are valid when the lens is focused at infinity. Infinity, Latin for “as far as the eye can see” will be a distance about 3000 focal lengths ahead of the lens. Light rays from objects that far forward of the lens arrive at the lens as bundles of parallel waves. The lens changes the direction of travel of arriving light waves. Their revised path will be converting rays that meet up at some distance downstream from the lens. A measurement of this distance is what we label as “focal length”. Since the lens as limited ability to refract (Latin “to bend backwards”) light rays from objects closer than infinity must travel further to make the convergences. We label this elongated travel distance “back-focus”. OK – how does “back-focus” effect explore as apposed to “focal length”? Suppose a 50mm lens is mounted an set to f/11. Since the f-number is the focal length divided by the aperture diameter, its diameter will be 4.55mm. The f-number tells us how this lash-up compares with other lenses as to light transmission. In other words, any lens set to f/11 grants the same exposing energy as another lens set to f/11. However, the f-number as engraved on the lens barrel is only valid when the lens is imaging an object at infinity. When doing close-up work, the object will be placed extremely close to the lens thus the back-focus will be extremely elongated. At magnification 1 (unity or life-size), the back focus distance is two focal lengths. A 50mm lens imaging at unity, the object will be 100mm forward of the lens and the focused image will be 100mm downstream from the lens. The distance focus plane to object is 200mm and the focal length is ¼ of this distance. Translated—The f-number for this 50mm lens is now computed as 100 ÷ 4.55 = 22 (written f/22. Thus, the engraved f-number is wrong and this error is called “bellows factor”. Macro to the rescue – The macro lens has a trick up its sleeve. The forward lens group of the macro is a powerful magnifier. The diameter of the iris (aperture), as seen peering into the lens from the front appears larger than life. This enlarged view functionally allows more light to traverse the lens when working in close. In other words, the macro self-corrects for bellows factor. Is this important? If a enlarger lens is used, no automation and no auto correction for bellows factor, Likely under-exposure results.

Allow me to continue --- Another way the film’s response to light is modified is also called “hypersensitization”. Formerly, astronomers used film exclusively when imaging. Films and plates often required a time exposure lasting many hours. Additionally, film undergoing super long exposure times entered into a characteristic we call “reciprocity failure”. We calculate an exposure based on scene brightness and ISO. Using this method, we arrive at the calculated long exposure time. To our surprise, under-exposure almost always results. This is because film speed plummets when the exposure time is exceptionally long. Astronomers generally work using super long exposure times and they find reciprocity failure provokes even longer exposure times. Clever physicists discovered they could soak the film in a chamber filled with special gasses. This method of hypersensitization ups the ISO and greatly relieves the effect of reciprocity failure.

I cannot speak about double exposure results. Seems I have tried to avoid double exposure ever since one or two ruined shots I was paid to take. That being said: A valid technique used to increase film speed (ISO) is a pre-flash. We set the shutter speed quite high and use a tiny aperture opening and image, out-of-focus, a uniform target like blue sky, white paper or screen or back-lit opal glass, is imaged. Such a quick (“flash”) exposure alters the film’s exposure threshold. This technique is called “hypersensitization”. Such a “flash” exposure is made just before the picture is taken. It can deliver a substantial speed boost. I think this is what is happening here. Your first exposure records an image and at the same time, hypersensitizes the film. Thus, the ISO is much higher when the second exposure is made. This might seem crazy but – during film manufacture the ISO of the film can be altered by a controlled flash exposure using different levels and colors. Additionally, a similar treatment, exposing the film briefly to selected chemical fumes is used. Often a super high-speed film is merely a slower cousin that has been so treated. Thus, the film has been “hypersensitized”. A “flash” technique is used in lithography along with a “bump” exposure. These are two methods used to control contrast in the process camera. “Process” cameras are giant size devices used to copy artwork and printed pictures. They contain a lamp positioned so that it can fog the film with a brief exposure. The camera is also equipped with a finely ruled screen placed atop the film. The screen fractures an otherwise continuous tone image into a myriad of dots. The result is called a “halftone”. To control contrast a “bump exposure is made, without screen. This technique increases highlight contrast. Conversely, a “flash” exposure with screen is used to decrease contrast.

Density is a measurement of the blackening. We measure the blackening of film which is a result of exposure and subsequent developing, using a unit called “density”. The root of this value is a delta of 2X. In other worlds, a change in exposure of 1 f-stop is equal to a doubling of halfling of density. By tradition the density unit is logarithmic. A 2X change in density equals 2^0.3 (2 elevated to the 0.3 power). In ordinary math notation this is 0.30 units of density. It goes like this: 1/6 f-stop = 0.05 units of density – 1/3 f-stop = 0.10 – ½ f-stop = 0.15 – 2/3 f-stop = 0.20 – 1 f-stop = .30 – 1 1/3 f-stop = 0.40 – 1 ½ f-stop = 0.45 – 1 2/3 f-stop = 0.50 – 2 f-stop = 0.60 – 3-f-stop = 0.90 – 4 f-stop = 1.20. This method dates back to the turn of the 20th century. Photo scientist used log notation because before the calculator, they used the slide rule. By the way, a gray card with 18% reflectivity reads 0.75. This is zone V, the calibration point for exposure.

I would suggest that you make friends with a local photofinisher (one hour photo shop). They have densitometers which they should be using daily to test their processes. In UK, many supplied by Noritsu, find their address and email and inquire about price of their densitometer.

Natural silver salts look white like salt but close examination shows they are off-white, somewhat cream to yellowish. This yellowish allows the silver salt crystal to absorb more blue light (reflects less blue). Dye additive alter the absorption - reflection of light. This is the stuff of sensitizing dyes. Dye additives plus adding impurities change the absorption and reflectivity. A pure silver salt is incentive to light. Finding a pure crystal is challenging. Adding impurities change the charge of the crystals from neutral to either + or -. This happens because impurities alter the structure of the crystal. Once a batch of Kodak film was ruined because the gelatin was contained due to the cows diet which in this case was wild mustard seed. To this day, some mustard is sprinkled into the batch. This contaminate and ups the ISO. Additions like this is called "doping". Many such containments are dye, gold, cadmium. Exposure to tiny amounts of mercury fumes up the ISO in a process called hypersensitization . Astronomers heat film in the presents of certain gasses. This hypersensitizes and mitigates reciprocity failure.

Most likely - Kodak Verichrome or equivalent. Natural silver emulsions are only sensitive to violet and blue. Sensitizing dye is routinely added to force the emulsion to gain sensitivity to the longer wave lengths such as red and green.