Martin Rickards
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Tetenal's Future
Martin Rickards replied to c_watson1's topic in The Wet Darkroom: Film, Paper & Chemistry
The problem for us is the amount of custom manufacturing they did for e.g.Ilford and Kodak.At present they still have a way to go before they even know whether the proposed management buy out will get through the German courts.If it does, there's bound to be some interruption to production. At the moment I'd recommend keeping fingers and toes crossed. -
Although the general advice on enlarging lenses is El Nikkor, Rodenstock or Schneider, there are numerous others and any 50mm from Photo Cornucopia with 5 elements or more should be OK for 35 mm. I've got the Opemus enlarger with a colour head, but you B/W version comes with a filter drawer that you'll need for printing variable contrast papers. It's a sturdy rather than sophisticated enlarger. One thing to be careful with is the lens mounting board which is domed in the middle. The dome is mounted upwards for 35 mm negatives and downwards for 6x6.
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Soda ash is routinely heated to much higher temperatures in e.g. glass manufacture (1500ºC) Also https://www.researchgate.net/post/Thermal_decomposition_of_Sodium_Carbonate The domestic oven can also be used for converting sodium bicarbonate (baking soda) to sodium carbonate
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??? I can remember from my lab days using sodium carbonate in platinum crucibles and heating it to red heat to fuse samples. Sodium oxide was not formed.
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Washing soda is usually, in England at least, the decahydrate and must be used at 286/106 x the rate of sodium carbonate anhydrous (soda ash).
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Fixer and the Environment
Martin Rickards replied to kathryn_treacy's topic in Black & White Practice
Chlorine is not per se an acid. It's hydrolysis products: hypochlorous acid and hydrochloric acid are. -
Fixer and the Environment
Martin Rickards replied to kathryn_treacy's topic in Black & White Practice
Strange as it may seem, the major use for rapid fixers (ammonium thiosulphate) is as a plant fertiliser. -
Does anybody help me?
Martin Rickards replied to lupacexi's topic in The Wet Darkroom: Film, Paper & Chemistry
There are basically two types of widely used fixers based on sodium thiosulphate and ammonium thiosulphate. Fixing times are different for the two with sodium thiosulphate based fixers always taking longer. The sodium salt is usually supplied in crystals and the ammonium salt in the form of a concentrated solution. http://imaging.kodakalaris.com/sites/prod/files/files/resources/edbwf.pdf -
Anyone Tried Ilford Ilfospeed RC paper?
Martin Rickards replied to Vincent Peri's topic in Black & White Practice
In the late 90's I did a lot of printing for a wedding photographer and invariably used Ilfospeed RC grade 2/3. Fairly straightforward in use.However long exposure times from Ilford XP negatives. -
Komuranon enlarging lens
Martin Rickards replied to robert_bowring's topic in Black & White Practice
It seems to be a six element enlarging lens and on the basis that if someone had set out to make a piece of crap, three elements would probably have sufficed, I'd say it's at least worth looking at. -
The halogens (iodine, chlorine and bromine, btw they are elements, not compounds) are not light sensitive (in the photographic sense), but it is the silver halides (iodide, chloride and bromide). It's like saying chlorine gas has a salty taste, whereas that's down to sodium chloride. With respect to RC paper, the likes of Ilford, Foma etc buy it by the km ready coated and apply the emulsion to it..