Lowering ASA of BW Film

Discussion in 'B&W: Film, Paper, Chemistry' started by Mustafa Umut Sarac, Jan 1, 2012.

  1. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    I have a 111mm f:1.5 Ektar large diameter lens without shutter or diaphram. I thought it would be fun to give film and lens long exposure times like old timers. My subjects are buildings , textures , my family and may be clouds.
    I can access Ilford FP4 and Kodak Tri X 120 Products , D76 , Ilford Phenidone and may be most widely available chemical powders from a Istanbul Seller.

    Is it possible to lower the ASAs of these films to 1, 5, or so. Is there a advantage ?

    My new camera will be 120,6x10cms back.

    Umut
     
  2. markbarendt

    markbarendt Subscriber

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    I don't know on the film but you could use neutral density filters on the lens.
     
  3. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Mark ,

    I read they are expensive and I dont want to wait for summer. Its winter and expenses are great. But for information , if someone knows what is the price of 6cms diameter one when looking at used ones classifieds generally ?

    I still want to know the film developer option also.

    Umut
     
  4. dnjl

    dnjl Member

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    Mustafa,

    I don't think it is possible to use a native ISO 125 or ISO 400 film at super low ISO values like you are describing. At least, I've never encountered anyone doing it. You can use neutral density filters as has been suggested, but they are indeed expensive. I'd suggest using a sheet of welding glass (10-15 stops difference). The results may not be as good as with a ND filter, but it does the trick if you don't want to spend a lot of money.

    Alternatively, you could just make paper negatives.
     
  5. Monophoto

    Monophoto Member

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    You cannot change the "ASA" of film. The ASA is a rating applied by the manufacturer based on industry-standard testing procedures. It is what it is.

    You can reduce the EI (exposure index) of film. I routinely rate my film at about half the ASA assigned by the manufacturer. I do that by means of testing under realistic exposure conditions (rather than the idealistic conditions that are the basis for the standard ASA tests).

    It is also possible to reduce the EI to less than what would result from practical testing. However - there is a limit. As you reduce the effective EI, you must also compensate with a change in development. A reduction in EI always means a corresponding reduction in development. The problem that you will encounter is that you don't want the development time to be shorter than 4-5 minutes - anything shorter is likely to lead to uneven development. You can also compensate by diluting the developer beyond the manufacturer's recommendations, but you eventually reach the point where the diluted developer doesn't contain enough active ingredients to develop the quantity of film you are working with.

    So if you are working with 'off the shelf' films of ordinary ratings, you will need to use a neutral density filter to force your exposure time longer.
     
  6. JPD

    JPD Member

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    You can of course use black paper and cut an aperture to mount in front of the lens. That's the cheapest alternative.
     
  7. Mackinaw

    Mackinaw Member

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    From what I read, certain developers, like Rodinal, can reduce a film's speed. Maybe a 1/2 F stop or so. Microdol-X, when it was around, could lower a film's speed about a full F stop.

    Jim B.
     
  8. Ian C

    Ian C Member

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    If you have two polarizers of the same size you can experiment crossing their axes close to, but not quite, 90 degrees. That gives you a great deal of neutral density cheaply. I did this to photograph a nearly total eclipse of the sun with a 300mm lens on a Nikon loaded with Kodachrome 25 in the 1990s. It worked well.

    You’ll have to experiment with a meter, such as that in an SLR, to determine precisely how many stops of light are held back by the pair of crossed polarizers.

    When you find the setting you want, you might want to draw a diagram of the relationship between the polarization axes indicator marks of the two polarizers so that they can be positioned in the same way relative to each other on the lens you use.

    Even if you don't cross the axes, the combination of the two polarizers will hold back about 10/3 = 3.3 stops lengthening the exposure by at least 8X.
     
    Last edited by a moderator: Jan 1, 2012
  9. rthomas

    rthomas Member

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    If they can get Ilford FP4, maybe the seller can also get Ilford Pan-F 50, which will give you EI 12 in D-76 or ID-11 at 1+3 dilution, 9 minutes at 20 C (according to the Massive Dev Chart). That's not quite ISO 1.5, but still very slow.
     
  10. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Thank you for all replies . I think I will follow Pan F route , I dont want to use cash as much as possible , so the expenses great. Playing with D76 is the cheapest route and I will look to massive development chart also. Suggestions for necessarty least 4 minutes development or double polarizer are great ideas.
     
  11. BrianShaw

    BrianShaw Member

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    Why not shoot directly onto enlarging paper. Slow and cheap.
     
  12. K-G

    K-G Subscriber

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    One film that may be right for you is the ADOX CMS 20 , now available in 120 size . According to Fotoimpex ( Berlin ) website, it can be used down to ISO 12 but I have heard of some photographers that go even as low as ISO 4 - 6 . It may be worth trying even if it will cost a litle more to send it from Germany. I enclose a link to the website for Fotoimpex. It use to be a non-problem company to order from.
    Good luck and a Happy New Year .

    Karl-Gustaf

    http://www.fotoimpex.de/shop/filme/...formatfilme-120/adox-cms-20-rollfilm-120.html
     
  13. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Happy New Year Karl Gustaf and Nice to meet you.

    Thank you for excellent tip. I know American Explorer and Photographer William Henry Jackson was using Glass 1 ASA Negatives. Details were better than todays Hasselblad pictures.

    Do you think I could get similar detail from 4 ASA or is it just only slow and thats it ? I always loved the idea to use extremelly low asa films and here it is .

    I will use lens with 35mm SLR Body and a Homemade Camera , 6x10 cms or wider if it is possible. When I put semi transparent paper , everything is very clear. I looked to the face of my mothers and I didnt see such a wild detail in my life , even Summmitar , Elmar and Summicron.

    Umut
     
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  15. ic-racer

    ic-racer Member

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    Rosco Cinegel #3404. Should be less then $10 for a 20x24 sheet. You can double it over if it is not strong enough. It is not 'optically perfect' but neither is that lens wide open.
     
  16. Jim Noel

    Jim Noel Member

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    You can not alter the ASA/ISO of any film. This is established by the manufacturer.
    You can alter your effective exposure index according to your equipment and method of processing.
     
  17. NB23

    NB23 Member

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    I'd buy a cheap colored filter with a 3 or 4x value such as a green filter.
    And I'd rate the film at half its speed at iso 50. This way you'd shoot at an effective ISO of 12 and you'd just have to slightly underdevelop and you can expect stellar results.
     
  18. Jim Noel

    Jim Noel Member

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    Jackson and his contemporaries used glass plates, a much more stable media than film. Also they made contact prints. these two factors alone will contribute to the difference in sharpness between their prints and enlargements from 120 film, or any other size, regardless of the quality of the lenses involved.
     
  19. jnanian

    jnanian Advertiser Advertiser

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    +1 !

    paper negatives would be perfect for this ...


    or just overexpose your film, and contact print your negatives using the sun or a bright light onto regular enlarging paper.
    i often times expose 400 speed film as 25 speed film process and print without any worries. 4-5 stops really isn't too much for tri x,
    ( it has a 7 stop latitude .. )


    good luck !
     
  20. K-G

    K-G Subscriber

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    Hello again Umut !
    The CMS 20 is an extremely fine grained film and if exposed and developed correctly will give you outstanding results. However it is not the easiest film to handle. I have used it myself in 135 size and grain size and resolution leaves nothing more to wish for. Developing the film was a bit tricky as you need the special developer ADOX ADOTECH . In some occasions you could get uneven development on large, evenly lit highlite areas. It also requires shorter fixing time as the emulsion is very thin and curling may also be a slight problem. These problems
    can be handled without to much effort.
    When the 120 version was introduced earlier this last automn, a modified developer ADOX ADOTECH II was also introduced. From what I have read it takes care of much of the problems with uneven development but I have not tried that myself. As Jim Noel writes, a glas negative and contact printing is superior but this film and an enlarger will take you a long way if handled in the right way. You may need to use a few rolls for testing. If you want to know more about it, send a mail to ADOX/Fotoimpex. They can correspond with you in both German and English. Mirko, their manager, is regularly answering question here on APUG.
    I hope it will work for you.

    Karl-Gustaf
     
  21. RalphLambrecht

    RalphLambrecht Subscriber

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    have you ever tried to makepaper negatives?they are a lot of fun iuse ilfordmgivrcwith ayellow filter at iso 3 for contct printing
     
  22. ooze

    ooze Member

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    Ralph, welcome back!!! Good to see you around here again.

    Re paper negs, they are fun indeed, but not very practical outdoors. You have to carry a changing bag and reload after each exposure.

    I tried paper negs after reading an article by Andrew Sanderson. But that was at home only.

    Cheers
     
  23. jnanian

    jnanian Advertiser Advertiser

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    naaah

    you can cut strips of RC paper and hand spool them ... and shoot in a regular camera instead of film ..
    i have been doing that with 122 format ( post card format ) for quite some time ...
    with a 120 format camera you might need 1/2 spools because of the (winder-)tension.
     
  24. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Thanks for all replies. I clearly understood , I cant change ASA of film , thank you for clearing this.
    ic racer ,
    Cine gels are good , I was thinking they were expensive for me , may be I can figure a gel or glass filter for the narrow back of the lens.
    But I have to stay in one digit expense like EDU, 120, 100 ASA, BW Film costs less than 3 dollars. Paper is difficult to store and Ilford Positive 4x5 ,25 Sheet paper cost me 18 dollars and makes 50 positives , not possible to roll as John said , and for same price Arista edu makes 70 bigger negatives and as a roll.
    I will use Gustaf route for Cosina SLR.

    Thank you all,

    Umut
     
  25. Bill Burk

    Bill Burk Subscriber

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    What would happen to film if you fixed it. Really short time in weak fixer, then washed and dried it. Would it lose speed but still hold some imaging ability? Is there a more appropriate way to desensitize film in a controlled way?
     
  26. jnanian

    jnanian Advertiser Advertiser

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    i would just test film exposed at a low asa and developed in a dilute developer
    OR
    if you can find instant coffee, sodium carbonate ( or bi carbonate to heat- force the water out of and covert to carbonate ) and vit c.
    spike it with a few ( 10-15cc/100cc of coffee developer) of your favorite print developer
    you can make a low contrast developer that you can stand ( 30-40mins? ) develop your over exposed film in, and it will turn out fine.

    have fun !
    john