Optical mask or ND grad?

Discussion in 'Exposure Discussion' started by Super Graphic Guy, Feb 14, 2003.

  1. Super Graphic Guy

    Super Graphic Guy Member

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    My objective is to controll contrast as when you use a Grad. ND filter, but overcome some of the problems they present. I want to capture as close to the final image on "FILM" while in the field. One that appears as close to how I see it naturally as I can. I know of the two exposure combine in photoshop technique, and they don't look natural to me, don't want to even discuss that route. So..................

    I have made some test exposures using just a simple cut out of cardboard slid into a Cokin filter holder, and lined up with the horizon. I first make an exposure of the forground with this mask in place. As the forground is darker this is the longer of the two exposures. Remove the mask and espose for the sky. It works! You can preciesly controll the brightnes range recorded on film with no color cast, and you are not limited to defined stops like my current list of grads. i.e. you can adjust brightness to with in 1/3 stop or what ever you want.

    Now for the real step. I would like to do this by cutting a mask to match an uneven horizon. Like say in a mountain setting. This would allow me to over come another problem with Grad ND filters, and darken only the areas I want to controll. I have tried it with uneven tree lines, and it taks time to get it right. It can be done, but very time consuming. Cut, view on GG, re-cut, view on GG, cut more, oops cut too much start over again. Yes, I am a masochist, thatÂ’s why I use LF in the first place.

    Any way, has anyone tried this before and just given up to live with currently available filters? Anyone found a quick way to match the contours of the horizon preciesly using this technique? Any suggestions, welcome. Yes I am crazy.
     
  2. Aggie

    Aggie Member

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  3. Donald Miller

    Donald Miller Member

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    While the means that have been described will undoubtedly work in some manner, it seems to me that the desired effect is more easily obtained in the darkroom with the use of masking of the camera negative.

    The reason that I make that statement is that the matter of cutting a mask to place over a camera lens is an onerous and imprecise method because of the matter of scale. With masking of the camera negative in the darkroom the effects of scale are greatly reduced and even eliminated if wished. If you have not already done so, I would suggest the articles written by Howard Bond in PT magazine on "Burn and Dodge" masking. This procedure is one that he learned from Alan Ross who does a lot of printing of the Ansel Adams photographs.

    While there is no one to tell you that you can't or even shouldn't pursue your methodology, it just seems unproductive to reinvent the wheel.

    Regards,
    Donald Miller
     
  4. lee

    lee Member

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    In black and white one can contol the overall contrast with exposure and development. This would be the way I would attack this. If you are using color materials, all bets are off. I think Donald is correct that contrast masks would be perfect for color materials. Ilfochrome printing or really any Type R technique would lend itself to contrast control masks.


    lee\c
     
  5. Super Graphic Guy

    Super Graphic Guy Member

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    Thanks for the suggestions so far.

    Folks I do color and B&W, but this is more for color, and my goal is to drop the transparency on the light table and have the final image with no or very minimal manipulations needed.

    What I really would like to know is if there is an easy way to match the contours of the scene in front of me when making the mask? Or am I faced with a frustrating process that is time consuming an fraught with imprecision? From my experience I think it is the latter, but if anyone has tackeled this problem and solved it with a modicum of success, please let me know.
     
  6. Donald Miller

    Donald Miller Member

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    I worked with color transparency materials a number of years ago. It seems that the problem of contrast control has always been a consideration in the use of these materials, especially when one attempts to make prints from these types of materials.

    If your aim is to make prints from transparencies and this is why you are trying to control contrast then the attempt to precisely do this in camera appears to be almost impossible to attain. Certainly, one can use graduated neutral density filters and they are effective in certain situations, but to precisely mask is another matter.

    I masked my transparencies, when working with that material, using a low contrast and low density black and white film mask. This became the negative of my positive transparency image. As such it added density were it was of lower value in the transparency and did not add appreciable density in higher density regions on the transparency. Using this method proved to be quite effective, in my experience.

    If you decide that you want to explore this method and have questions, you will probably find others who have worked with this procedure. I will also be happy to share what my limited experience has been. Good luck.

    Regards,
    Donald Miller
     
  7. Jorge

    Jorge Inactive

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    Is very simple super and it worked for me really well, I only did it once and it was one of those begginners luck results. Once I saw on a TV program back when they had TV programs about photography how one professional photographer made a composite by putting a glass in front of an 8x10 and then placing masks he would cut. Sort of doing what Donald is doing in the darkroom or the photoshop thing. But since I did not have all that money etc, I thought, well why cant I just place a clear filter and fill the area with a marker. One of those big tip indelible markers. What would you know that it worked great! I had this scene where I was shooting a difference of 13 stops, and I wanted the walls inside as well as the stuff outside the "hole" in full sun to have detail. So I tried it and it worked, and this was on 35 mm.....So if you can find anything that would block light competely you can draw it on a filter and make two exposures. one for your foregorund and one for the sky...Actually what I would get now would be a can of spray paint and then remove the paint on the part you want to come through. Of course you would have to carry the paint ,solvent and q tips, maybe is not a good idea. How about one of those black grease markers?
     
  8. Super Graphic Guy

    Super Graphic Guy Member

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    Thanks so much for the suggestions. It is good to have a group that is not demeaning of oddball ideas.

    Jorge, your suggestion gave me an idea I will try today. I bought a sheet of Plexiglas. I am going to cut it to the width of the filters I use. I will attempt to compose the scene on the GG, and then hold up the cut Plexiglas and look through it. No camera, and match the perspective I see on the GG. Take a sharpie pen and outline the contour of the horizon. With this as a template, I can then cut the cardboard to match. This might produce more accurate results than just trial and error. I will report on the trial latter.

    Thanks again for the suggestions and the positive tone of the site.
     
  9. Super Graphic Guy

    Super Graphic Guy Member

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    This procedure works, and is less of a trial and error way of doing it. I haven't made any exposures yet, but matched an outline on plexiglass and cut the cardboard mask. Just slide it into the filter hodler and adjust the height. The whole procedure takes less than 5min, and can be easily repeated.
     
  10. Super Graphic Guy

    Super Graphic Guy Member

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    Just got back the first test exposure using this technique. Makes for great balance between foreground and sky, but one must be very careful about aligning the mask. I shot the first try using a fence as my dividing line, and if you don't stop the lens all the way down to the taking apeture, you will be fooled on it's placement. You will wind up with either a bright line or a dark one that will destroy your work. The same as with a Grad ND, but here the error is more evident as you are totally masking the sky. It does look as if it is more difficult to use than Grads, but it can and should produce more precise results.
     
  11. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I think Cokin sells some sort of clear filter for precisely this sort of thing. Maybe Roscoe has some kind of clear acetate that would work and without introducing optical problems, and shouldn't be too expensive in large sheets.

    Another option is to use a matte box or compendium shade with a holder for masks on the front standard. These used to be popular for hokey vignettes and such, but can be used for custom masks cut from black paper or plastic sheet. You can feather the edge of the cut to blend it. If you hunt around on eBay, you can find the Ambico Shade+ fairly cheaply, if you don't want to spring for a Lee system or something fancier, but be sure it comes with adapter rings (or at least one large enough to use with step-up rings on your system), and note that the adapter rings for the Ambico 3x3" filter holder are different from the rings for the Shade+ (which also holds 3x3" filters on the rear standard, as well as masks on the front standard). The Shade+ comes in both a square and rectangular format versions.
     
  12. Super Graphic Guy

    Super Graphic Guy Member

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    " You can feather the edge of the cut to blend it."

    David,

    How would you suggest to feather the edge? My process is to take the contour marked on the plexi-glass and cut a cardboard mask that will fit in my Cokin holder. Then carefully line up the edge of the mask while looking through the stoped down lens. I then make my two exposures on the same frame. Feathering the edge would make lining up things a little less critical. As it is now the process makes the ultimate hard edge, and allignment has to be bang on.

    Any suggestions would be appreciated.
    Thanks
     
  13. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    The old vignette masks achieved this feathering just by cutting a jagged, toothed, edge instead of a smooth line, and since the mask is close to the lens and way outside the DOF range, it produced a softer effect. There are scissors available in craft shops that cut various kinds of jagged, deckeled, or toothed edges, so maybe there is one that might work well for this purpose.