Using filter on BW and chrome

[jumanji]

1. I never used filter before.
2. I know nothing about Photoshop.

So my question might be silly, but please educate me: Is using filter (Color compensating, color correction) on chrome film really necessary, if we can adjust the image in PTS after scanning? Are they all about color temperature, color cast, color shift?

I've acquired a lot of Kodak Wratten filters, and I will use them to shoot chrome as well as BW. May you suggest me a good book or an online document/article on using filters?

Thanks in advance.

[Heroique]

Lots of ways to address your question.

As for me, I like displaying transparencies on an old-fashioned overhead projector. That means I need to "get it right" at the time of the shot. So I have my filters ready to use in the field, if needed. Often, however, I don't need them.

For b/w filters, Ansel Adams has a wonderful chapter in The Negative. See Chapter 5, "Filters and Pre-exposure." For example, here are four observations that have helped me judge the conditions of light before selecting appropriate filters:


1. The sun gives warmer (redder) light early and late in the day. Clear blue sky is very strong in blue, violet, and ultraviolet, especially at high altitudes.

2. A clear blue sky gives colder (bluer) light than hazy or partially cloudy sky in which the haze or clouds scatter sunlight.

3. The light on an overcast day is about the same color temperature as the light from sun and clear sky.

4. Shadows illuminated by open sky are colder (bluer) when the sky is clear than when it is misty, partly cloudy, or overcast.

Now that's what I call practical and useful tips!

[jumanji]

Thanks Heroique. Yes I did read The Negative and AA has some useful tips, but there is almost zero on using filters with chrome film.

[Heroique]

Are you mainly using chromes for landscapes in natural light, or for architecture spaces in artificial light – such as fluorescent/tungsten/mercury vapor? If the latter, Norman McGrath's Photographing Buildings Inside and Out is one very good introduction for on-site filtration for chromes.

[polyglot]

B&W really only needs filters for gross tone placement, i.e. Red, Yellow, Green, Blue and CPL. Absolutely no point in using the subtle conversion filters because most B&W films have uneven spectral response anyway.

For colour, yes you must use the filters before exposure because they prevent problems with differing non-linearities in the three/four separate dye channels. In the most extreme case, consider shooting a daylight film in tungsten light. If you expose for the red, the blue channel will be 2 stops under-exposed (shadows will have hue shifts). If you expose for the blue, the red channel will be 2 stops over-exposed (highlights will have hue shifts) - either way, you're going to lose a bunch of highlight detail or shadow detail or both, especially on chromes. If you use the proper conversion filter, the orange/red will be attenuated and you get a balanced exposure which will look good and give you the full dynamic range of the film.

For more subtle colour issues you don't need much, say just an 81B for shooting in the shade or evening. You don't need to get it to the nearest CC unit. Of course, negative is far more forgiving, especially if you give it a little extra exposure.

[jumanji]

Thanks guys. Oh well, now I need not only book on filters but also books on theory and practice of color/chrome film photography. Any suggestion?
I also need a color meter, right?

[polyglot]

No need for a colour meter unless you are doing super-critical work for print where you need to match the colour of photos taken in different locations. You basically eyeball it: shoot daylight film, no filter in daylight, 81B in shade/evening, 80B or 80C for tungsten (depending on the bulbs), FL-D for fluorescent. That about covers it.

[jumanji]

Thanks. I will have to burn quite a lot of film to get something acceptable. Just browsed Amazon and add some books to the list.

[swilf]

Thanks guys. Oh well, now I need not only book on filters but also books on theory and practice of color/chrome film photography. Any suggestion?
I also need a color meter, right?

Well, using color meter is not really necessary. You just throw away many sheets of exposed transparency that look dull until you realize that buying a color meter right from the start would turn out to be less expensive :)

[jumanji]

I'm watching some color meters as well.