Shooting B&W Film Through a Red or Orange Filter...

Discussion in 'Black and White' started by Vincent Peri, Jan 12, 2021 at 12:27 AM.

  1. Vincent Peri

    Vincent Peri Metairie, LA

    I was researching whether or not a medium yellow filter is needed when shooting modern B&W film. And then I found this article:

    Using Colour Filters for Black & White photography

    It says you need to overexpose 1 stop if using an orange filter, and 1 to TWO stops if using a red filter because your camera meter is fooled by the filters! I never heard of such a thing.

    The only thing I can figure is that they meant to say a hand held meter not reading through the filter will give the wrong exposure.

    Comments...?
     
    Last edited: Jan 12, 2021 at 12:38 AM
  2. Best technique with TTL metering is to meter without the filter and then apply the appropriate filter factor after fitting the filter - in fully manual exposure mode obviously.

    Otherwise the spectral response of the metering sensor might give an incorrect exposure (could be either over or under). The meters in older cameras weren't particularly well colour corrected. But then again the red response of B&W film varies considerably too.

    Basically it's not an exact science.

    A quick experiment I did some time ago showed that a polariser gave about the same effect as an orange filter with a blue sky.
    Filter-comparison.jpg
    The neutral grey of a polariser shouldn't upset a TTL meter as much as a coloured filter.
     
    kmac and Vincent Peri like this.
  3. In my case the exposure adjustment depends on the camera. My 35 mm SLR sets aperture though the lens, so it compensates for the filter factor. My 4x5 view camera does not so I have to do the adjustment.

    My problems with filters is they change more than the sky. They shift all the colors somewhat. I have found that even though the filter improved the sky/clouds, it also changed the color contrast of the other objects in the shot. The polarizer seems to have less impact on the overall contrast but the degree of darkening the sky depends on your angle to the sun light.

    The trick of course is to shoot enough that you learn how the filter/polarizer will impact the entire scene. For that I like to practice with my digital.
     
    Last edited: Jan 13, 2021 at 11:42 PM
    glen_h likes this.
  4. There are quite a few earlier film cameras with built in meters that are not TTL. I suspect the comments relate to these & yes would also be relevant for off camera metering.
     
  5. Sandy Vongries

    Sandy Vongries Administrator Staff Member

    In film days, Nikon specified filter factors for their filters and a comprehensive sheet came in the box with each filter purchased. There is a great deal of detailed information in the Nikon Nikkormat Handbook by J.D. Cooper in the Exposure Control section. I have several of the sheets that came with filters, when I find one, I'll copy and post it. If you are interested, I can scan the book pages and send you a PDF.
     
  6. Vincent Peri

    Vincent Peri Metairie, LA

    Hi Sandy.

    I should have one of those filter info sheets somewhere around here.

    You don't need to send me a PDF, since I'm going to buy a copy of the Nikon Nikkormat Handbook on ebay. Thanks for the offer, though.
     
    Sandy Vongries likes this.
  7. Sandy Vongries

    Sandy Vongries Administrator Staff Member

    I have found it very useful. Initially I had the hard bound, but there was a sort of Club for Advanced users under EPOI, and they issued a set of three ring binders and periodically sent out updated pages. I would recommend the latter if you can find it.
     
  8. Most subjects aren't polarized, but reflections off water often are.

    The other on is rainbows, which polarize the same way as the sky.
    If you darken the sky, the rainbow goes away!
     
  9. Most reflected light is polarized. And most, if not all, light we see and photograph is reflected. So using a polarizer will always have some effect.
     
  10. Well, camera meters are often fooled, but it looks like they are doing more that that.

    Note that proper rendering of red objects is somewhat dark, which is how we know that they are red.
    That is, red is a naturally dark color. (Consider a red, white, and blue flag. The blue should
    be darkest, the red somewhat dark, and the white light. If the red isn't dark, it will
    look wrong.)

    If you meter through a red scene, then the whole scene is red, and a correct exposure meter
    will make the whole scene dark. Since you don't want that, one extra stop.
    Or you can read it as a TTL meter doesn't correctly compensate.

    It might be that your scene doesn't need that, but then the latitude on black and white film
    (unless you are using reversal film) will easily take care of it.

    What it says for the orange filter is a filter factor of 4, so 2 stops.
    You can test this, metering with and without the filter, and see how much
    difference it makes. Note especially that scenes with a lot of green,
    grass and trees, will get a lot darker. Others might not.

    Exposure in the case of colored objects is an inexact science, and even
    more through filters. As most films are designed with one stop of underexposure
    tolerance, you will likely be fine, unless you are already using that.

    If you look at the data sheets for Kodak ISO 400 films, they recommend
    the same development times for one stop (EI 800) push. That is, they use
    the underexposure tolerance.
     
  11. Vincent Peri

    Vincent Peri Metairie, LA

    Thanks! That's good to know.
     
  12. Filter Facts by Feininger. 1950-10 Modern Photography
    Filter-Facts-(Feininger)-1950-10-MP.jpg
     
  13. If I'm reading the question correctly, that is not the question being asked.

    Rather, the question is-do TTL meters correctly compensate for colored filters?

    I'd guess, just to lay everything out, that both the film's spectral response and the spectral response of the meter will dictate that.

    One of the fancy 3D multi-pixel color meters like Nikon advertised for the F5, F6, and F100 probably don't need any help on a normal pan film like Tri-X.

    An old CdS cell might well be a different story.

    As Joe said, the best bet in fact likely is to meter without the filter and then apply the factor indicated in the film datasheet.
     
  14. James G. Dainis

    James G. Dainis Moderator

    The advantage of a polarizer is it reduces glare or shine to make colors richer.

    polar_back_two.jpg

    Even in black and white the loss of glare makes a difference but some people may prefer the unpolarized sharper lookingversion. polar_back_two_bw.jpg
     
  15. Yes, but I think it is even more than that.

    I suspect that even if the cell has the exact wavelength dependence as the film, it will still be wrong,
    though maybe close enough. Most of the time we ignore this, and it is probably fine.

    As well as I know, the subject mostly comes up with ordinary light sources.

    Some black and white films say "Use blue bulbs for flash", though in earlier days it was
    common to use clear bulbs. To get the correct gray rendering for colored objects, the difference
    between clear and blue bulbs shows up. (Even though I suspect I couldn't tell the difference.)

    Proper gray rendering for red objects is a somewhat dark, but not too dark, gray.
    I suspect we don't think about this, but when we look at a black and white picture,
    we usually know what different gray tones mean.

    An object reflecting 100% of the red light hitting it should photograph as
    a somewhat dark gray. But with a red filter, we don't want everything
    to come out somewhat dark gray, as a proper meter will give it.
     
  16. Over the years (I started in the mid 1970's) as I used colored filters with black & white, I quickly learned to bracket exposures. Later meters (not CDS) often handle red filters a little better (IMHO), at least for scanning. I haven't tested selenium cells with red (and other) filters in a while but if I hold a red filter up to the front of the meter cells on my Rollei B35 the exposure seems to be correct or at least close. YMMV.
    During my college days one of my favorite filtering combinations was to combine a #25 red with a polarizing filter. Depending upon the area of blue sky included in picture one could get some inky black skies.
     
  17. Using filters, you block a part of the light, to selectively darken part of the image. The meter doesn't know what you are aiming for, only registers less light coming through. So it compensates. Which you do not want it to do. It would raise exposure for the parts not affected by the filter, and of the part you want to darken using the filter. I.e., 'compensation' results in both a lesser effect of the filter (though not relative to the other parts of the scene) and an overall overexposure.
    If the filtering is very selective, you should meter without filter and apply the filter factor as provided manually. Basically, you do not want to change exposure at all, except for the bits held back by the filter. So if the filter would not hold back any of the other light, you would not need 'a correction', need not change shutterspeed or aperture at all.
    If the filtering is less selective lowering exposure of most parts of the scene (just not by equal amounts), you could use the built-in meter.
     
    Mike Gammill likes this.
  18. I am curious how you meter a polarizer. The recommendations say to vary up to 1 1/2 or 1 3/4 stops. I may not use the full effect at times, So I'll add maybe a stop. But I never really tried metering through it. Can that be done accurately?
     
  19. When i use a polarizer, i meter without and set the fixed filter factor that is printed on the filter. You do not want to counter the selective effect of the filter. Only compensate for the general, non-specific light loss caused by the thing.
     

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