Photoshop theory: A deeper understanding of the color in the photo studio palette Optional Colors command

This tutorial focuses on the optional color commands in the studio palette, which is originally used to print a method of restoring scan separations, which is used to change the number of process colors in each primary primary color component of the image. Since the optional color can selectively modify the number of printing colors in any major color without affecting other major colors, it is now becoming a sharp weapon in the later digital adjustment, and we can adjust the colors we want to change with an optional color to preserve the colors we do not want changed.

Before I introduced the Curve tool, the curve is strong in its control points, and the advantage of the optional color is that you can adjust each of the primary colors without affecting the other colors. As far as learning is concerned, the curve is a tool that is easy to understand but difficult to operate. And the alternative color is just the opposite, is easy to use but the basic theory is difficult to palm, but in order to better in the later color control, some basic knowledge must know, so that in the color palette has a certain understanding of the results.

(Note: RGB is slightly different from the color changes in the alternate colors in CMYK mode, and the optional color is not available in Lab mode.) This article is an optional color for use in RGB mode. )

One, intuitive panel, ...

The first part, the adjustment of ink content cmyk--cyan, magenta, yellow, black

In each of the main colors, we can change the green, magenta, yellow, black, or CMYK ink quantity to achieve color adjustment. Because the optional color is originally used for printing school color, so its adjustment is based on the original ink color, in addition to the three primary colors in addition to a black slider, where the black and CMYK in the K slightly different, Although all are black but K refers to in the printing because the limitation of the pigment does not match the real black, so the extra black ink added to the printing color, is a separate ink. But the alternative color of the black is in the ideal, refers to the CMY of the three primary colors mixed with black, so we do not understand the black here as a color, but as a mixture of three primary colors. may be accustomed to in RGB mode, CMY such ink calculation method is not too familiar with, that we remember cyan, magenta, yellow three kinds of ink primary colors RGB color is the complementary color of the three primary colors became.

The second part, method: relative and absolute

The relative and absolute is the ink increase and decrease the amount of two different calculation methods.

Change the amount of existing cyan, magenta, yellow, or black relative to the percentage of the total. For example, if you add 10% from 50% magenta pixels, 5% is added to magenta, with the result 55% Magenta (50% * 10% = 5%). (This option does not adjust the pure anti-white light because it does not contain color components.) )

Absolute color adjustment is absolutely used. For example, if you start with a magenta pixel of 50% and then 10%, magenta inks will be set to a total of 60%.

In practical applications, we can simply understand the relative and absolute differences, the same conditions usually relative to the color of the change is less than absolute, and the relative options for the ink does not exist. The absolute option adds a nonexistent ink color to one of the primary colors in the image. The highest value of the ink is 100%, the lowest value is 0%, the relative and absolute value of the calculation can only change in this range.

[Note: If the complex color, because the same color of different primary colors, so the calculation method is more complex, can not only rely on simple formulas to apply. ]

Part III, adjustable primary colors (main color)

1. Adjustable main color is divided into three groups

RGB Three primary Colors: red, green, blue

CMY three primary Colors: yellow, cyan, magenta

Black and white gray brightness: white, black, neutral color

2. The performance of adjustable colors on the color loop

The color gamut of each primary color is represented on the Hue ring as shown below.

We can see from the picture, in the color classification, we can affect each kind of main color and so on the similar color, as deviates from the main color angle is bigger, then receives the control force to be smaller, until disappears.

In the lightness category, pixels with a black RGB value of less than 128 are selected, and the neutral color is selected for removing the most black spots and the most white dots, and the pixels for each value greater than 128 are selected.

When we select a range, you can drag the slider that needs to be adjusted, respectively, to change the pixel in the range of ink three primary colors and black values to adjust, the choice of color adjustment color The biggest advantage is that you can adjust a single component, and will not affect the other two.

When you adjust black, the numerical changes are equivalent to three components at a time.

Second, intuitive principle, get rid of the color of the mask

Many users use the optional color tools are usually masked, the color of the results do not have any intuitive feeling. Completely adjusted by feeling, before the application of the later curve of the photo studio I talked about the adjustment of the curve, and the elegant curve adjustment compared to the optional color more emphasis on the data more rational. Optional colors with a wide range of selection features allows us to target the color of the image to correct or adjust but in the application of color tools, often this happens, we based on our intuition or experience to choose, such as adjusting the sky or the background of plants and so on, Often in the adjustment we think that the choice of the correct color, can move the adjustment slider is not to change the color of the results we want, we know that the character color should choose red or yellow, adjust the sky choose blue or cyan, adjust the high light selection white, adjust the shadow select Black, But sometimes because of color temperature or environmental color reasons some intuition is not completely correct, which requires our specific situation specific analysis, this analysis is based on what I want to talk about.

1. Color Matching of Primary colors

Before the article, the alternative color is used for printing in the reduction of the scanning color separation technology, so in the adjustment we must understand the color of a variety of ink colors:

Red = yellow + Magenta

Green = blue + Yellow

Blue = cyan + Magenta

Knowing the color, we know that red, green, blue (RGB) These three colors are ink color (CMY) of the colors, so as to understand the color of the main color RGB and CMY relationship, Red can be separated from the yellow and magenta, yellow plus cyan ink can be green and so on such a color relationship we should firmly remember, Only in this way can be more concise use of alternative colors, so that the color changes in our hearts.

2. Complementary color mixing

Because the optional color palette is a subtractive method, the complementary colors are mixed as follows:

Green + red = green + (yellow + magenta) = Black (gray)

Green + Magenta = (cyan + yellow) + Magenta = Black (gray)

Blue + yellow = (cyan + Magenta) + yellow = Black (grey)

(Note: In the additive method, the complementary color adds the result color to be white.) )

This article has been introduced in the beginning, the color of the choice of black for the same amount of primary colors mixed, so black and gray can be separated from the three primary colors, which is very common in the practical application of the optional Color tool, In particular, the current popular photo tones often in the dark or neutral gray area add a little color of the main color or contrast color to increase the colour contrast of photos, feeling very fashionable, is the use of black separation principle, and other tools to achieve this effect is very complex.

3. For example

So mastered the color principle of the choice of colors we can use the optional Color tool before we know how to change the color to get the color we want, can be confident to adjust the color.

Because the optional color with the amount of ink to determine a certain color, we through the above color laws can be known to change the main color of a color of the slider to get the results of what color. For example, pure red, we can see through the information Panel in the pure Red cyan ink content of 0.

So under the relative method, adjusting the Cyan slider has no effect on the red.

Red = yellow + Magenta, red is a combination of yellow and magenta, so increase the magenta ink content as red + Magenta = yellow + Magenta + magenta, because the magenta ink content has reached saturation, so the result is still yellow + magenta, so the result color is still pure red will not change. And the magenta pigment content minus 100%, as red-magenta = yellow + Magenta-magenta = yellow, so the result color is yellow.

Move the yellow slider, increase the yellow ink content as red + yellow = yellow + Magenta + yellow = Magenta + yellow, the result color is still red. The yellow pigment content minus 100%, as red-yellow = yellow + Magenta-yellow = magenta, so the result color is magenta.

Move the Black slider, as at the same time acting on the C, M, y three components, so increase the black ink to 100%= red + Magenta + yellow (because there is no cyan ink in red, so do not add cyan ink in this formula) = red + red = red. Reduce black ink to -100%= red-magenta-yellow = red-red = no ink = white.

4. The difference between the colors and the primary color adjustment

Pure red is yellow and magenta ink original colors, which can be seen in the law of color change: For red, green, blue, such as the colors of ink, through the green, magenta, Yellow ink slider adjustment can be made up of this color ink. But if the direct adjustment of ink primary colors will get what kind of results?

Now use the main color for the primary colors of the primary colors of the slider movement of the results to demonstrate the change of the original ink color.

[Note: The bright yellow purity of 0%, 0%, 100%, 0% in CMYK mode is higher than 255, 255, 0 yellow in RGB mode]

Through observation can know, because the yellow itself is a kind of ink color, so in light yellow for the adjustment of the main color, C, M, K ink content is 0. So the method in the relative, cyan, magenta ink no matter how the adjustment will not change the color, and yellow ink results are still yellow, minus yellow ink to -100% as without ink, the result is white; adjust the Black slider as if you were adjusting the yellow slider.

(in CMYK mode slightly different, do not do this in this narrative.) )

This shows that the original ink in the relative method, only move its primary colors and black slider can affect the result color, when its ink reduced to 0 when the white.

5. Adjustment table of various colors

Other ink colors and complementary color changes can be referred to red, yellow color changes, according to its color principle to understand the resulting color. In an optional color, the method adjusts to a variety of primary colors as follows:

Main color ink minus 100% plus 100% result color result color

Red:

Green -100←0→+100 red ← Red → Red

Magenta -100←0→+100 yellow ← Red → Red

Yellow -100←0→+100 magenta ← Red → Red

Black -100←0→+100 white ← Red → Red

Yellow:

Green -100←0→+100 yellow ← Yellow → Yellow

Magenta -100←0→+100 yellow ← Yellow → Yellow

Yellow -100←0→+100 white ← Yellow → Yellow

Black -100←0→+100 white ← Yellow → Yellow

Green:

Qing -100←0→+100 yellow ← Green → Green

Magenta -100←0→+100 green ← Green → Green

Yellow -100←0→+100 Green ←

Black -100←0→+100 white ← Green → Green

Cyan:

Green -100←0→+100 white ← Green → Green

Magenta -100←0→+100 green ← Green → Green

Yellow -100←0→+100 green ← Green → Green

Black -100←0→+100 white ← Green → Green

Blue:

Green -100←0→+100 Magenta ← Blue → Blue

Magenta -100←0→+100 green ← Blue → Blue

Yellow -100←0→+100 blue ← Blue → Blue

Black -100←0→+100 white ← Blue → Blue

Magenta:

Green -100←0→+100 Magenta ← Magenta → Magenta

Magenta -100←0→+100 white ← Magenta → Magenta

Yellow -100←0→+100 Magenta ← Magenta → Magenta

Black -100←0→+100 white ← Magenta → Magenta

At this point, I believe that readers should have a certain understanding of the changes in the color of choice, but the real change is much more than that, and in the above discussion the attentive reader will certainly notice that I have repeatedly stated above that the changes in the above colors are produced under relative methods, and that the options for alternative colors are relative and absolute. The following section shows the color changes under absolute methods.

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