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I know color filters "block out" colors opposite to the color of the filter, and when used in black & white photography, can brighten or darken the object depending on its color and the color of the filter.

So I was wondering, when doing b&w photography, is there something like a "go to" color filter for portraits, some that smooths skin tones, etc.? Or is it situational, depending on our lighting conditions, to compensate for color casts caused by environment, or blocking out colors in the background, making the person seem brighter to make them pop, or something like that?

Edit: I should note I was primarily asking for film black & white photography, but it is always good to know both sides, so answers for digital are also appreciated.

  • Are you shooting film or digital? – D. Jurcau Jan 25 '17 at 17:13
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    In addition to Rafael's excellent explanation, for portraits, red will tend to show skin as smoother and blue will tend to bring out freckles and other variations. They give a very different look. Blue can be very striking, see: google.com/search?q=portrait+blue+filter&tbm=isch – Dietrich Epp Jan 26 '17 at 1:58
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There is a really important diference if you are using film or is a digital photo. I will focus on Digital aspects but will give you an idea of what to expect with film.

The method I am using is simply using the primary channel of a colour RGB image.

Let me start with primary light colors RGB. As the skin has more red component the skin will look brighter when using a red filter (R) and the oposite hapens when using green (G) or blue (B) filters.

enter image description here

Panchromatic film is already taking into account more green in the light spectrum than red and blue, that are on the extremes of visible light spectrum, so the tendency will look more like the green sample(G)

But modern color profiles and conversion tools uses a more complex combinations than simple color filters as you can see on the sliders of a grayscale conversion.

enter image description here

In this case, the default conversion profile renders less contrasted results (P) with more gray tones and gives a result simmilar to the lightness component (From an HSL color model) (L).

enter image description here

blocking out colors in the background, making person seem brighter to make them pop, or something like that?

You normally use a color filter on film if you wanted to contrast something in the background, like the sky for a more dramatic one using red filters for example.

If you use color filter on a digital camera you drasticly reduce the amount of photons to produce an image, the amount of lightness levels and the posibility to play with the grayscale conversion.

There are some digital filters and software tools that help you event to simulate how classic b/w films reacted to light, so:

Simply shoot in RAW and in full color and play later with the conversions.

(Original photo: https://pixabay.com/en/redhead-hair-scarf-eyes-face-1828099/)

  • I've shot portraits on digital before. Best option is yes, shoot in RAW and convert to B&W in post-processing. That way you can fine-tune the effect to bring out the features you want (you'll also have more than just colour filters to work with - contrast, curves, gamma, etc.). Plus you'll be able to produce a colour version as well if desired. In my case, I was aiming to produce a colour, B&W, a colour-toned version of the same portrait. – Micheal Johnson Jan 25 '17 at 20:44
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    Remember also that you can usually set your camera to B&W mode even if you're shooting in RAW - you'll still get the colour information in the file but the on-camera preview will be in B&W, which can be helpful to get a rough idea of how your shots will look. – Micheal Johnson Jan 25 '17 at 20:44
  • There are limited scenarios when the use of a filter in front of the lens when shooting digital (raw) will reduce shadow noise at the expense of longer exposure or wider aperture. For more please see: photo.stackexchange.com/a/80576/15871 – Michael C Jan 26 '17 at 5:35
  • It doesn't have to be only one or the other (glass filter or software). It can also be both. In certain situations you can reduce shadow noise significantly by attenuating the light you don't want in your final image with a filter before you record it digitally. This allows higher exposure of the light you do wish to record. You can then apply the same digital tools as before to fine tune and differentiate even further. But the closer you get the light before it hits the sensor, the better your ultimate image quality should be because you won't have to pull the shadows up as much. – Michael C Jan 26 '17 at 5:37

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