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  1. #11
    RalphLambrecht's Avatar
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    Quote Originally Posted by fschifano View Post
    Softness due to diffraction is dependent upon the actual size of the iris opening, not the f stop which is nothing more than a ratio: focal length / aperture size. A lens with a focal length of 80 mm. will have a smaller f number than a shorter lens given the same sized opening. That's why you can stop long lenses down a lot more before diffraction problems begin to show up.
    Frank

    Good note, but I don't think this statement is correct. Since diffraction is an angular deflection, it is the aperture vs. projection-distance that counts, and therefore, it IS the f/stop that counts. See the graphs attached.
    Attached Thumbnails Attached Thumbnails Diffraction.jpg  
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  2. #12

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    Not necessarily to be recommended but on a night school B&W printing course we students all tended to leave our early evening prints in the communal water bath for maybe an hour or more while we got on with other prints. Prints were eventually passed throught a heated roller RC dryer. I used Ilford RC paper. Never noticed any problems.

    pentaxuser

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