True or False

Discussion in 'Film Discussion and Q & A' started by Actor, Sep 29, 2009.

  1. Actor

    Actor TPF Noob!

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    1. A powder developer, such as D-76, must be kept from light and air until it is mixed. This means that you must mix the entire envelope at one time. For example you cannot open a package "to make one gallon," extract 1/4 the power, mix one quart, put the remainder back in the package and reseal it. You must "make one gallon" (or whatever).
    2. #1 is also true for powered fixer and other chemicals.
    3. Once mixed into a "stock solution" developers must be kept from oxygen but light will not harm them.
    4. #3 is also true for fixers and hypo-clear.
    5. Even though tables give developing times for temperatures ranging from 66˚ to 76˚ best results will always be obtained at 68˚.
    6. Arista Premium film is actually Kodak film.
    7. Legacy Pro film is actually Fuji Neopan.
    8. Arista.edu film is actually Fomapan.
    9. Overexposing film by one stop, then pulling it one stop in processing, will reduce grain, contrast and acutance.
     
    Last edited: Sep 29, 2009
  2. ann

    ann No longer a newbie, moving up!

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    1. true
    2. true
    3. depends
    4. true, all packaged chemicals need to be mix
    5 false, films can be developed at a wide variety of temperature, folks tend to use 68 as a standard to maintain consistence processes. times need to be adjusted to reflective the change in times.
    6. I don't know, but am doubtful that Kodak would do this type of re-banding
    7. don't know
    8 don't know
    9. contraction will certainly reduce contrast as that is it's main function, and when one reduces development time the main stay of the zone system recommendations an ajustment with over exposure . Whether it will reduce grain, may be a side effect as over development certainly does increase grain which also effects the edge effects .
     
  3. Randall Ellis

    Randall Ellis TPF Noob!

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    I agree, as usual, with Ann on this one, with the following additions:

    #3 This is true of some developers but not of others. Unless you know for certain it is best to err on the side of caution. Read the manufacturers recommendations to be sure - they generally know their product better than people who post on internet forums, having conducted extensive scientific testing...

    #5 [anecdotal evidence warning] I develop all of my films at 80 F, because that is the temperature of my tap water, and I have negatives that, in my humble opinion, are very easy to work with and which produce very good results. I have used temperature control devices and found no discernible difference in the results (other than exceptionally long development times)...

    #6 I believe that Plus-X is rebranded in this way, but that belief is based soley on anecdotal evidence. I do not know of any specific statement to this effect by either Freestyle of Kodak. That said, Freestyle does not make film - they rebrand other manufactures and Kodak could be one of the suppliers.

    #9 Contrast is controlled by a combination of exposure and development - read more here. Edge effects can be accentuated by dilution of developer and by reduced agitation in most films. Some developers are better at doing this than others, but this is a topic that requires some research. The same can be said for apparent grain, although different films also exhibit more, or less, apparent grain. Be aware that apparent grain directly affects apparent sharpness - the more prominent the apparent grain the sharper looking the results, and vice versa.

    - Randy
     
  4. Actor

    Actor TPF Noob!

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    My thanks to both Ann and Randall.

    Interesting that you develop at 80˚. I've been told that the tables Kodak publishes are restricted to the 66˚ to 76˚ range because you are not supposed to get out of that range. Also interesting that you say "that is the temperature of my tap water" because at least one book I have says that the temperature of tap water varies widely, although I suspect such variance is seasonal rather than hourly.

    Recently I wandered into the pet department at the local Wal-Mart and found a device that is supposed to keep the temperature of the water in an aquarium at 77˚F (I guess fish like 77˚). It occurred to me that I might be able to do my processing at 77˚. The thing only costs $15.

    I've heard that too, but Plus-X is faster than Arista 100 and Kodak recommends a shorter developing time for Plus-X than Freestyle recommends for Arista 100, so I doubt that Plus-X = Arista 100. But Arista Premium could still be Kodak film. Freestyle says that Arista Premium is "manufacturered in the United States" by "a major film manufacturer." Kodak is the only company I know of that fits that bill. The same line of reasoning would support Legacy Pro = Fuji.

    So more grain goes along with sharper edges? Does that mean faster films (more grain) give sharper edges (greater acutance)?

    Short aside here. One of my cameras (Pentax PZ-20) allows you to set the film speed to ASA 6. That's intriguing. Why would anyone need ASA 6? I wonder what would happen in I exposed Efke KB 25 at ASA 6 and pulled it two stops?
     
  5. Randall Ellis

    Randall Ellis TPF Noob!

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    When I lived in Columbus (Ohio) the water temperature did vary through out the year, but I live in Florida now and it's always 80 straight from the tape year round. This will really knock your socks off - I keep my AC set to 80 in the summer :eyebrows: when it's 99 outside keeping it set any lower than about 80 just runs up the electric bill and makes it feel even hotter outside when you leave the house.

    As for temperatures, I've no idea about Kodak products - I don't use their films or chemicals - but with modern films in general, the emulsions are much harder than they used to be, so temperatures up to 80F (and perhaps higher), as long as they are consistent from start to finish, will not damage the film in any way that I am aware of.

    Edge effects give more apparent sharpness because they increase the local contrast of the parts of the image where there is already some contrast - it's very roughly like drawing a black line around the edges of something printed on white paper. Unlike edge effects, grain allows the eye to be able to resolve the everything in general - think of how much easier it would be to see a pattern drawn in marbles from 10 feet away than it is to see that same pattern drawn in grains of sand from the same distance - it's easier for the eye to pick out the details when they are larger.

    Faster films do tend to exhibit more apparent grain than slower films, but developers also play their part in that respect. You can reduce apparent grain in faster films by using a solvent developer, and you can increase apparent grain in slower films using an acutance developer. I find that using slower films (I prefer Pan F+ and FP4+) with a dilute acutance developer (I use Rodinal 1:100) will give more pleasing results than using a faster film (Tri-X or HP5 for instance) with a straight solvent developer (Perceptol or Microdol-X, or even D-76 stock), but that is a completely personal judgment not intend to be read as a statement of fact. Some prefer the look of faster films developed in dilute solvent developers, which gives somewhat different results - the more dilute the developer, generally speaking, the more edge effects it exhibits and the less solvent action it has (Solvent meaning that it reduces the apparent grain).

    I recommend that you read Barry Thornton's book 'Edge of Darkness' for a better idea of how this works because I'm not really much of a technical expert and his explanation is very approachable...


    Film used to come in those low speeds quite commonly. It's only been in recent times that we've gotten up to 400 and above film speeds. You can, if you adjust the development, expose it that way if you want, but the results will be somewhat different that what you get at box speed. Look for different developers that tend to 'lose speed' for that type of work...

    - Randy
     
    Last edited: Oct 1, 2009
  6. CSR Studio

    CSR Studio TPF Noob!

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    Kodak used to make a beautiful film called Tech Pan, it was rated at 25 but most shot it at 15, and processed normally. It makes for a beautiful negative, especially architecture and landscapes. Too bad they don't make it anymore.
     
  7. ann

    ann No longer a newbie, moving up!

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    ah, tech pan.

    i wonder if they are still making "blue fire police", very very very sharp film, altho strange to look at as the base is clear which is always mind bending to an old fashion traditional worker.

    I would second Barry's book, i have a copy someplace on the book shelf.
     
  8. Randall Ellis

    Randall Ellis TPF Noob!

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  9. ann

    ann No longer a newbie, moving up!

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    thanks randy, i was much too lazy to check out google :er:

    it is a very interesting film and years ago , i spent a few months testing and playing around with it, not sure why i stopped.
     
  10. Randall Ellis

    Randall Ellis TPF Noob!

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    I didn't search either - I just happened to have it in my bookmarks :)

    - Randy
     
  11. Dwig

    Dwig TPF Noob!

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    1. You have multipe claims here and very poor logic so technically the correct response to #1 has a whole is "false". It breaks down like this:

      1a powder developer must be kept from light
      false

      1b powder developer must be kept from air
      true

      1c This means ... must mix the entire envelope...
      false in that 1a and 1b do not pose any restrictions on whether or not the whole envelope must be mixed at once so 1a and/or 1b don't mean that the whole package must be mixed at one. In fact, 1a is false which alone invalidates the assertion. 1b does, in practical terms, mean that the unused portion can't be relied on later but does not, in and of itself, mean that the first sample isn't usable. What is true about mixing the whole package is that the power is a mix of several difference powders which very different mechanical particle or crystal sizes and different densities. This means that it is virtually impossible to mix the powers in such a way that any measured part of the mix contains all of the components in exactly the proper percentages. It is this mixing problem that makes it necessary to mix the whole package at once and not the sensitivity of some components to oxygen and some to moisture in the air.


      As to #2, again since #1 is a mixed bag of multiple assertions #2 can't get a simple answer:

      2a: oxygen sensitivity - false
      2b: light sensitivity - false
      2c: mix eveness - true just like #1, you must mix the whole package for purely mechanical reasons.

      The overlooked sensitivity in both the case of developers and fixers is moisture. Once you open the package, moisture is absorbed out of the atmosphere. This can cause issues of its own in addition to the fact that moisture water which contains a lot of oxygen, though they are small with fixers. You can never reseal a package without trapping and excessive amount of oxygen, either in gas form or as a component of H20.
     
  12. compur

    compur No longer a newbie, moving up!

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    Have you seen that Rollei has a film claimed to be a replacement for Tech Pan?

    See:
    Rollei ATP1.1 Advanced Technical Pan Film

    I haven't tried it yet.
     

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