Explanation of ps channel, calculation, application image and mixed mode

1. Mixed mode

First of all, we must clarify a concept, that is, the relationship between "base color", "mixed color", and "result color", that is, "base color" + "mixed color" = "result color". The base color refers to the image layer to be processed, the layer above the base color layer. In fact, "mixed mode" refers to the calculation method between "base color" and "mixed color". In "mixed mode", each mode has its own unique calculation formula, which is mainly divided into 6 groups, a total of 27 kinds , Each set of blending modes can produce similar effects or have similar uses. For example, the first group: combined normal mode, the second group: dimming mode [darkening mode], the third group: brightening mode [lightening mode], the fourth group: saturation mode [contrast mode], the fifth group: Difference mode [comparison mode] and the sixth group: color mode [color mode].

Normal mode

1. Adjusting the opacity of the upper layer in the "normal" mode can make the current image and the underlying image have a blending effect.
2. "Dissolve" mode: It is characterized by adjusting the opacity to create a dot spray image effect. The lower the opacity, the more scattered the pixels.

Deepen blending mode : Deepen blending mode can compare the current image with the underlying image to darken the underlying image.

3. Darken mode: The characteristic is to process areas that are darker than the current image. Pixels lighter than the mixed color are replaced, and pixels darker than the mixed color remain unchanged. No change when mixed with white.
4. Multiply: The characteristic is that all areas except white will darken the base color. Note that any color combined with black produces black. Any color combined with white remains unchanged. No change when mixed with white
5. Color darkening: The feature is to strengthen dark areas. The principle is to darken the base color by increasing the contrast to reflect the mixed color. No change when mixed with white.
6. Linear darkening: The linear darkening mode is similar to the multiplying mode, but the contrast effect is stronger, which is equivalent to the combination of multiplying and coloring. The principle is to darken the base color by reducing the brightness to reflect the mixed color. There is no change when mixed with white.
7. Dark color: Compare the sum of all channel values ​​of the mixed color and the base color and display the smaller color. Compared with the image effect obtained in "Darken" mode, you will find that the difference between the two is that using the "dark" blending mode will not produce the third color, and the color in the image will not change. You can clearly find it from the result color. Where is the color of the base color and where is the color of the mixed color.

Dodge blending mode : In PS, each of the darkening modes has a completely opposite dodge mode. The feature of the dodge mode is that the black in the current image will disappear, and any area brighter than black may be brightened The underlying image.

8. Brighten mode: Brighten mode and darken mode have the opposite effect. Select the lighter color of the base color or the mixed color as the result color. Pixels whose primary color is darker than the mixed color keep the primary color unchanged, and pixels brighter than the mixed color are displayed as the mixed color. The color remains the same when filtered with black.
9. Filter mode: The complementary color of the mixed color is compounded with the base color, and the resulting color is always a brighter color. The feature is that it can make the image have a bleaching effect. The filter mode and the multiply mode have the opposite effect. The color remains the same when filtering with black, and filtering with white will produce white.
10. Color Dodge Mode: Lightens the base color to reflect the mixed color by reducing the contrast. The feature is that it can brighten the underlying image while making the color more saturated. Due to the limited changes to the dark area, it can maintain a better contrast. Mixing with black does not change.
11. Linear dodge mode: The base color is brightened by increasing the brightness to reflect the mixed color. It is similar to the filter mode, but can produce a stronger contrast effect. Mixing with black does not change.
12. Light color mode: The third color will not be generated because it will select the largest channel value from the base color and the mixed color to create the resulting color. Same as the difference between "dark" mode and "dark" mode, the principle of "light" mode and "brighter" mode is basically the same, except that the third color is different.
13. Contrast blending mode: It combines the characteristics of the burn and dodge modes. When blending, 50% of the gray will disappear completely. Any area brighter than 50% gray may brighten the image below, and the area darker than 50% gray It is possible to darken the underlying image, thereby increasing the image contrast.
14. Overlay mode: The feature is that when adding color to the underlying image, the highlights and shadows of the underlying image can be maintained. (Compound or filter colors, depending on the primary color. The pattern or color is superimposed on the existing pixels while retaining the contrast of the primary color. The primary color is not replaced, but the primary color is mixed with the mixed color to reflect the brightness or darkness of the primary color.
15. Soft light mode: brighten or darken the color, which can produce a finer effect than the superimposed mode or strong light mode. If the mixed color (light source) is brighter than 50% gray, the image becomes brighter as if it is lightened. If the mixed color (light source) is darker than 50% gray, the image becomes darker, as if it has been darkened. Painting with pure black or pure white will produce noticeably darker or lighter areas, but will not produce pure black or pure white.
16. Strong light mode: The strong light mode is characterized by increasing the contrast of the image, which is equivalent to a combination of multiplying and color filter. This effect is similar to shining a bright spotlight on the image. This is very useful for adding highlights and shadows to an image. Painting with pure black or pure white will produce pure black or pure white.
17. Bright mode: The characteristic is that the mixed color is more saturated, which can make the image produce a bright feeling, which is equivalent to the combination of color dampening and color deepening. Darken or lighten colors by increasing or decreasing the contrast.
18. Linear light: The characteristic is to make the image produce a higher contrast effect, so that more areas become black and white, which is equivalent to a combination of linear dodge and linear deepen. Darken or lighten the color by reducing or increasing the brightness.
19. Point light: The feature is that the color can be replaced according to the mixed color. It is mainly used to make special effects. It is equivalent to a combination of brightening and darkening modes. If the mixed color (light source) is brighter than 50% gray, the pixels darker than the mixed color are replaced without changing the pixels brighter than the mixed color. If the mixed color is darker than 50% gray, the pixels lighter than the mixed color are replaced without changing the pixels darker than the mixed color.
20. Real-color mixing: The characteristic is to increase the saturation of the color and make the image produce the effect of tone separation.
21. Comparison blending mode: The comparison blending mode can compare the current image with the underlying image, and then display the same area as black, and different areas as grayscale or color.
22. Difference mode: The white area in the mixed color will make the image inverted, while the black area will be closer to the underlying image. The principle is to subtract the mixed color from the base color, or subtract the base color from the mixed color, depending on which color has a greater brightness value. Mixing with white will invert the base color value; mixing with black will not change.

**Exclusion mode: **Exclusion mode can produce a softer effect than difference mode. Create an effect similar to "Difference" mode but with lower contrast. Blending with white will invert the base color value. Mixing with black does not change.

23. Subtraction mode: The value of the base color is subtracted from the mixed color, which is similar to the difference mode. If the mixed color is the same as the base color, the result color is black. In the difference mode, if the mixed color is white, the result color is black. If the mixed color is black, the result color is the base color unchanged.
24. Dividing mode: the base color splits the mixed color, and the color contrast is strong. After reading the example picture, we directly use several special colors as examples. In the division mode, if the mixed color is the same as the base color, the result color will be white. If the mixed color is white, the result color will remain the base color. If the mixed color is black, the result will be the same. The color is white.

Color mixing mode : The three elements of color are hue, saturation and brightness. When using the color mixing mode to synthesize an image, PS will apply one or two of the three elements to the image.

25. Hue mode: Use the brightness and saturation of the base color and the hue of the mixed color to create the resulting color. This mode can apply the colors of the mixed color layer to the primary color layer image and maintain the brightness and saturation of the primary color layer image.
26. Saturation mode: The characteristic of the saturation mode is to make certain areas of the image black and white. This mode can apply the saturation of the current image to the underlying image and maintain the brightness and hue of the underlying image.
27. Color mode: The characteristic is that the hue and saturation of the current image can be applied to the underlying image and the brightness of the underlying image can be maintained. The grayscale in the image can be preserved, and it is very useful for coloring monochrome images and coloring color images.
28. Brightness mode: The characteristic is that the brightness of the current image can be applied to the underlying image, and the hue and saturation of the underlying image can be maintained. This mode creates the opposite effect to the "color" mode.

The various hybrid modes have been mentioned above, and they should be selected according to the purpose when they are used.

2. Calculate and apply images

Regarding channel mixing in PS, **"Calculation" and "Apply Image"** are two command tools that must be mentioned. What is the difference between them?

1. "Calculate" to create a channel, and "Apply Image" to transform the channel.

"Calculation" can only generate new Alpha channels (or new selections, new documents), but cannot transform existing channels, so it is mainly used to make selections. The "application image" is just the opposite. Its result is solidified in the primary color channel participating in the mixing, so it actually plays a role in transforming the primary color channel.
The calculation is to use two image sources to recalculate a new channel or selection through the blend mode, and to apply the image, it is directly applied to the target image after the calculation is directly performed on the existing image with the image source through the blend mode.

The main differences between the two are as follows:

1. The "gray" channel in "calculation" is different from the "RGB" channel in "application image".

The "gray" channel in "calculation" has a fixed meaning, that is, the image after the image is transformed into a grayscale mode. The "RGB" channel in "application image" has different meanings depending on different mixing environments: (1) The "RGB" channel in the target channel refers to the RGB composite channel. (2) The "RGB" channel in the source channel has different meanings depending on the target channel. When the target channel is also the "RGB" channel, the "RGB" channel in the source channel also refers to the RGB composite channel; when the target channel is a separate channel, the "RGB" channel in the source channel is the same as the "Calculate" command. The images are all converted to grayscale.

2. The opacity is considered differently in the generation of the resulting color scale.

The "Calculate" command only considers the "opacity" in the panel in the way of filling opacity, and does not consider other opacity, such as pixel opacity, layer opacity and filling opacity, etc.

"App image" is more complicated:

When the source channel selects "Merge Layer", the opacity of the mixed color, the opacity of the layer and the opacity of the fill, and the "opacity" in the command panel will be considered simultaneously in the way of filling opacity.

When the source channel does not select "Merge Layer", it is also related to the target channel. If the target channel is a color channel, only the "opacity" in the command panel will be considered in the form of fill opacity; if the target channel is an Alpha channel, the pixel transparency and command panel of the mixed color will be considered in the form of fill opacity "Opacity" in the, regardless of the opacity of the layer and fill opacity.

3. Different understanding of constituencies.
When there is a selection in the image, "Calculate" will ignore the existence of the selection, but "Apply Image" does not, and the blending will be limited to the selection.

The third point is very important.