Notion of colorimetry

Additive synthesis :

The principle of additive synthesis is simple, using only the three primary colors that are red, green and blue, one obtains the white. Mixing them in different proportions will give all other colors. The two-by-two mixing of the primaries will give a twice lighter color which is the complement of the third.
This synthesis principle is known as RGB (Red, Green, Blue) in the Anglo-Saxon countries and RVB (Rouge, Vert, Bleu) in the French countries.
The additive synthesis is used by the screens, and is made up of the three basic lights. In RGB, secondary colors are brighter than primers, which is why their synthesis is called additive.

  • The complementary color of cyan is red.
  • The complementary color of yellow is blue.
  • The complementary color of magenta is green.
Subtractive synthesis :

Subtractive synthesis is very often associated with primary CMY (Cyan, Magenta, Yellow). The mixture of the three primaries will give the darkest color of the system which ideally should be black. To offset the disadvantage of a non-perfect black, the graphics industry uses a fourth color to complete or replace trichromatic black. This system, based on CMY blends reinforced by the black color, is called four-color process (CMYK).
Subtractive synthesis is used in printing.
If we mix two primary colors, the result will be a darker secondary color that will absorb more light to that is why this synthesis is called subtractive.

  • Black with cyan, magenta and yellow filters.
  • Red with magenta and yellow filters.
  • Green with yellow and cyan filters.
  • Blue with magenta and cyan filters.

Black and White Digital Photography

The black and white photo is an art in its own right, It brings a dose of mystery, timelessness, and magic to the images. Some textures are often magnified by black and white.
To make a good picture in black and white, it is preferable strong contrasts as well as many different shades of gray. In black and white as there is, by definition no color, one can only play with light tones and dark tones.
The passage of a black and white photo is mainly based on two techniques:

  • 1 - The retouching of the contrast and brightness of certain areas of the image.
  • 2 - The retouching of the brightness of certain colors of the image.

Process a Black & White photo in Capture One Pro

The retouching of the brightness of certain colors of the image (technique n ° 2) is specific to the conversion of an image in black and white. In some software applications you can apply color filters, the effect of which is similar to the color filters used for silver photography.
The filters have the particularity of stopping a part of the wavelengths corresponding to their complementary colors. They let through the wavelengths corresponding to their own colors. Thus, they attenuate their own color while strengthening their complementary color.

Filters in Capture One Pro

In Capture One Pro, the black-and-white conversion tool is based on this principle of color filtering:
The first four filters correspond to those used in silver photography, sometimes with different gradations, the last three filters allow refinement of the filtering.

  • Red filter: Primary, for lightening reds and strongly darkens the blues and greens, strongly reinforces the clouds and dramatizes a blue sky.
    (red 100%, green 0%, blue 0%)
  • Yellow filter: secondary, to lighten the yellows and darken the blues and violets. Ideal filter for the landscape.
    (red 50%, green 50%, blue 0%)
  • Green filter: primary, to lighten greens and darken the reds, perfect for photos of vegetation.
    (red 0%, green 100%, blue 0%)
  • Orange filter: tertiary, for lightening the reds the yellows and the oranges, darkens the blues and the violets.
  • Cyan filter: secondary, lets Cyan but also Green and Blue, it stops its complementary color, the Red.
    (red 0%, green 50%, blue 50%)
  • Blue filter: Primary, to improve the catches from afar by accentuating the mist. It stops red and green.
    (red 0%, green 0%, blue 100%)
  • Magenta filter: secondary, it stops its complementary color, green.
    (red 50%, green 0%, blue 50%)
  • The Primaries are: Red, Green and Blue.
  • The complementary colors: Magenta, Cyan, Yellow.
  • A Secondary corresponds to the addition of two Primaries in equal parts.
  • A Tertiary is obtained by adding, in variable proportions, a primary and a secondary.

For a given color, its complementary color is that which, added together with it and having nothing in common with it, will give the White.

The Black and White tool and its filters in Capture One Pro.

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