1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Quick filter question

Discussion in 'Lens Matters' started by ajbendel, Dec 4, 2017.

  1. ajbendel

    ajbendel New Member

    Hi, I've only ever used digital equipment till now. I've been given a film camera and some filters including a B+W 49ES CTO 12B. Obviously this is a 49mm size, but can anyone tell me what the filter does and what sort of film it should be used with? Many thanks.
     
  2. Andrew Flannigan

    Andrew Flannigan Well-Known Member

  3. PeteRob

    PeteRob Well-Known Member

    There were queries back in 2005 on the forum about B+W filters not being listed in the hand-book.
     
  4. GeoffR

    GeoffR Well-Known Member

    I think the 12B is important and I am fairly sure it is a contrast control filter for use with black and white film but I cannot recall what a 12B filter is or does in any detail. Can you tell us what colour it is?
     
  5. RogerMac

    RogerMac Well-Known Member

    Afraid that I can not help you with the 12B but these pages from a 1957 manual might help
    a1.JPG A2.JPG
     

    Attached Files:

    • a1.JPG
      a1.JPG
      File size:
      320.6 KB
      Views:
      1
  6. ajbendel

    ajbendel New Member

    It's orange.
     
  7. RogerMac

    RogerMac Well-Known Member

    There you go:) Just remains for you to start some interesting experiments as to whether that table still works. If you are using an external meter don't forget the necessary exposure compensation suggested in the final column but ignore that if using an internal (post filtration) meter
     
    Last edited: Dec 4, 2017
  8. Andrew Flannigan

    Andrew Flannigan Well-Known Member

    Which knocks the KB12 theory on the head - that's pale blue. If it's definitely orange and not a sort of reddish brown then it's a straight forward filter for monochrome film as per Roger's table.
     
  9. Benchista

    Benchista Which Tyler

    CTO stands for Colour Temperature Orange, and 12B means it's a warming filter for colour (slide) film, although you could use it as a contrast filter for B&W.
     
  10. ajbendel

    ajbendel New Member

    Brilliant, thanks so much everyone. I bought some Tri-X recently, so hopefully the filter will work well with that.
     
  11. RogerMac

    RogerMac Well-Known Member

    Please post some of the results
     
  12. steveandthedogs

    steveandthedogs Well-Known Member

    And let us know what the camera is!

    S
     
  13. GeoffR

    GeoffR Well-Known Member

    Thanks Nick, I couldn't remember what the 12B was, should have looked at my old reference books instead of Google.
     
  14. Learning

    Learning Ethelred the Ill-Named

    Great. It was most likely intended for B&W, but there's now't to stop you experimenting with colour!
    For B&W it will darken blue skies rather more severely than green or yellow; it will darken grass and other greenery.
    Now in the old days experiments with filters and film would take days and much expense. These days just regress to your digital camera, select B&W, and experiment to find out what the fiter does.
    Almost forgot, you asked for what sort of film it was intended for. Answer B&W Panchromatic.
     
  15. Learning

    Learning Ethelred the Ill-Named

    Nick's answer is more accurate than mine. Sorry It was for colour. I was wrong. But it still works as I decribed for B/W pancromatic.
     
  16. Chester AP

    Chester AP Well-Known Member

Share This Page