Jump to content

Martin Rickards

Members
 View Profile  See their activity

  • Posts

    36

  • Joined

  • Last visited

 Content Type 

Everything posted by Martin Rickards

  1. Martin Rickards
    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.
  2. Martin Rickards
    Having used both the Fuji and Meopta, I'd say the latter is better built and will prove more durable. I had to throw the Fuji away when the clamp holding it to the column failed. Meopta's Meogon lenses are very good. Only the Opemus 7 will accept 6x7 negatives; all others take a max of 6x6.
  3. Martin Rickards
    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.
  4. Martin Rickards
    The sodium thiosulphate will probably still be OK. It's sold as the pentahydrate salt, is very stable and its effectiveness can still be judged simply on an old film leader in case of doubt.
  5. Martin Rickards
    I use the Meopta Vipo timer. 25+ years no problems.
  6. Martin Rickards
    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
  7. Martin Rickards
    ??? 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.
  8. Martin Rickards
    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).
  9. Martin Rickards
    Chlorine is not per se an acid. It's hydrolysis products: hypochlorous acid and hydrochloric acid are.
  10. Martin Rickards
    Strange as it may seem, the major use for rapid fixers (ammonium thiosulphate) is as a plant fertiliser.
  11. Martin Rickards
    My Meopta colour enlarger also has a neutral density filter of about two stops for just such a situation.
  12. Martin Rickards
    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
  13. Martin Rickards
    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.
  14. Martin Rickards
    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.
  15. Martin Rickards
    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..
  16. Martin Rickards
    A couple of points. The silver halides are chloride, bromide and iodide; the chlorine, bromine and iodine are chemical elements. RC papers are simply plastic coated (usually polythene), with no complicated laboratory processes. Hypo clearing agent is usually sodium sulphite, not sodium chloride based.
  17. Martin Rickards
    It makes you wonder why it's still being used after being introduced in the XIX century:D
  18. Martin Rickards
    The number of people that swear by brand x, y or z would lead me to believe that there is no best enlarging lens. This may be due to several reasons, starting from there probably being some degree of quality variation among lenses of the same manufacturer, different levels of care of the lens, subjective opinions about what is good, enlarger set up etc.I'd hazard a guess that, as a general rule, most 3-4 element lenses are not as finely corrected as 5,6 or more element ones, though those of us who only enlarge to 8"x10" from 35mm would need a loupe to notice any difference if any. For those doing, say, 15-20x enlargements, the difference is probably noticeable.
  19. Martin Rickards
    I'm fairly happy with the alignment and I'm not posting my test results, but merely pointing out results published on a French website. Strangely enough a google search for the lens gives many French pages and very few English ones. My own 35 mm enlarging lens is a Minolta 50 mm f2.8, which seems good enough for me.
  20. Martin Rickards
    I use an Opemus 6, which has no adjustments for aligning either the optics, negative stage or the illumination. All I can do is check that the projected image is square on the baseboard.
  21. Martin Rickards
    Since writing about the Meogon, I have noticed on Photo Cornucopia that it is in fact a wide angle 6x6 cm lens rather than a standard 35mm lens. That may have something to do with the excellent results obtained using it for the smaller format.
  22. Martin Rickards
    Apparently ammonium thiosulphate is a useful fertiliser. It is sold generally as a 60% solution, but I have never been able to find any in less than bulk quantities. With reference to the above post, I wrote thiosulphate, not because it is archaic but because that is how it is spelt in British English. Sulphur is also correct, as is litre. PS If you don't like "spelt" either get a good British English dictionary.
  23. Martin Rickards
    That gives the rather unhelpful "love rating".
  24. Martin Rickards
    I've got no idea. I'm not sure if it's some value for money ranking. However, even the discontinued lens with no price scored, so that can't be it. Google doesn't differentiate between "cote" and "côte":(
  25. Martin Rickards
    As I speak French very badly, I can only state that in the introduction distortion of between 0.1 or 0.2 is considered the limit of measurement. My own opinion is that variances in quality between the same lenses are probably as great as those between some different lenses. If I were offered a Rodagon or Meogon, I'd try them both to see, but I doubt whether I'd be able to see much difference.
×
×
  • Create New...