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  1. #1

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    Wratten Filter Question

    In the market for a Series 6 #21 orange filter; not too many around. I am seeing a fair number 85s A, B, C; does anyone know (not guess, please) if one of these can be substituted for the same B + W contrast effect?

    Many thanks all.
    Cogito, ergo Bebop a Lula

  2. #2
    AgX
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    Not for the same contrast. The filter characteristics beetween conversion- and contrast filters are too divers.

    But, depending on your subject you could gain some contrast effect. That would be for deep blue subjects. Due to the matter it is hard to be more precise.

  3. #3

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    Colored filters like the typical series yellow -> orange -> red are NOT contrast filters. These filters darken blue objects like the sky but overall do not change the contrast of a scene. An orange filter will lighten objects that are yellow or orange in color. It would be helpful to study the color wheel which gives the relations between the two sets of primary colors. Calling them "contrast filters" is a common but erroneous designation.

    The following may be of help to you. http://motion.kodak.com/motion/Produ.../wrattten2.htm
    Last edited by Gerald C Koch; 06-08-2015 at 07:38 PM. Click to view previous post history.
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  4. #4
    AgX
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    If a part of the scene gets darkened or lightened, then this changes the contrast within the scene.

    Kodak themselves use the term contrast filter.

    As any other manufacturer, author or encyclopedia I can think of at the moment.

  5. #5

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    Quote Originally Posted by AgX View Post
    If a part of the scene gets darkened or lightened, then this changes the contrast within the scene.

    Kodak themselves use the term contrast filter.

    As any other manufacturer, author or encyclopedia I can think of at the moment.
    The trap is in thinking that the contrast of the entire scene is increased. Think of a scene that contains only black, gray or white objects. You're not going to see any increase in contrast with an orange (or any other colored filter). Only a polarizing filter can do this without changing the relative contrasts between some objects the scene.
    Last edited by Gerald C Koch; 06-08-2015 at 08:08 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  6. #6
    AgX
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    A polarizer changes contrast as well as those "contrast" filters, may it be by darkening a sky, a window or a specular reflection.

    All these filters can as well change gross- or detail-contrast. Depending on circumstance. And thus of course applying the term "contrast filter" just on some coloured filters is questionable. But this is the terminology as it has evolved.

    Another issue is the definition of contrast. As seen by applying development variations or those filter.
    Last edited by AgX; 06-08-2015 at 08:26 PM. Click to view previous post history.

  7. #7

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    Quote Originally Posted by AgX View Post
    But this is the terminology as it has evolved.
    The dumbing down of technology.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  8. #8

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    If your zone 1 shadow is 'open shade' then a minus blue filter will convert it to zone 0?

    That is a detectable increase in contrast in the negative?

    Any change in contrast is dependent on scene, filter spectral response & film spectral response.

  9. #9

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    Quote Originally Posted by Gerald C Koch View Post
    Colored filters like the typical series yellow -> orange -> red are NOT contrast filters. These filters darken blue objects like the sky but overall do not change the contrast of a scene. An orange filter will lighten objects that are yellow or orange in color. It would be helpful to study the color wheel which gives the relations between the two sets of primary colors. Calling them "contrast filters" is a common but erroneous designation.

    The following may be of help to you. http://motion.kodak.com/motion/Produ.../wrattten2.htm
    Well, yeah, kind of. By altering the spectrum the film sees, it's not technically a contrast filter but a gamma shift in the red, green and blue response by the chosen film. However, one could effectively argue the effect of the bandpass alteration via filter will have the net effect of a contrast change in the final print, per filter color. To cite your example an orange filter--will block a goodly portion of blue light, darkening a clear blue sky and lightening brick buildings. The orange will also darken shadows illuminated by skylight and make differences in cloud values more pronounced. Not to overlook foliage values; sounds like another way to express "contrast change" to me..!

    Ultimately one can argue over the semantics ad infinitum--of which I am guilty. To wit, "Reciprocity Failure" is a term like "irregardless"--jangles my nerves. There actually is no such thing as reciprocity failure, it is reciprocity effect (more accurately, the Schwarzschild effect) regarding non-linearity of EVs over expected exposure times at reduced or the reaction of film to excessive luminance, e.g., "black suns". Over the years, I've learned to quit browbeating fellow photogs over it. (But not the use of "irregardless"--a man has to draw a line somewhere...)

    I understand what everyone means, my own focus is what gets onto the paper.
    Last edited by Monday317; 06-08-2015 at 11:46 PM. Click to view previous post history.
    Cogito, ergo Bebop a Lula

  10. #10
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    I've always interpreted "Reciprocity Failure" to mean the inability of the photographic material to behave consistent with the assumption that all the various combinations of exposure times and light intensities resulting in the same Exposure Value will give the same result.

    Really a failure of the assumption, rather than the material.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

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