Color Adjustment of Photoshop

It's hard to calculate how many people now use "Photoshop5.5"-there are too many people using computers, too many people using computer graphics, and almost all people who use computer graphics have more or less knowledge of Photoshop5.5 ...

Ask a very retarded question: what is the most wonderful thing about Photoshop5.5?

Channel? Layer? Filter?

These answers are all right! But I thought: the most wonderful place in Photoshop5.5 is "color adjustment". Oh, personal views, for your reference only.

Go and see??

(Figure 1)

The menu in Figure 1 is the "adjust" command, which is located under the Graphics menu, which includes: levels (levels), auto levels (automatic levels), auto contrast (automatic contrast), Curves (curve adjustment), color Balance (color Adjustment) , Brightness/contrast (brightness/contrast), hue/saturation (hue/color saturation), desaturation (removal of color), replace color (replace colors), selective Color (selected color), Channel Mixer (channel mixer), Invert (invert), equalize (equality), Threshold (Threshold), posterize (tonal Separation), variations (change), and so on.

Among them, levels, auto levels, auto contrast, Curves, brightness/contrast mainly adjust the contrast of image, they can change the distribution of pixel value in the image and adjust the hue in certain precision range. Levels, Auto levels, color Balance, selective color can adjust the color balance of the image, Hue/saturation, Replace color, selective color, Invert, Equalize, Threshold, posterize, variations, and so on can modify specific colors in the image. Next, we will make a detailed statement of these instructions ...

First, the "Levels (level)" instruction ...

Now, let's open an image to get a look at levels (Figure 2)

(Figure 2)

Select the "Levels" command under the Adjust submenu under the Image menu to bring up the levels (Level command) dialog box shown in Figure 3.

(Figure 3)

Next, a few parts of the Levels dialog box are described:

1. Channel Option Bar

Let's see what he looks like. (Figure 4)

(Figure 4)

Through the channel options bar of the Levels dialog box (where the options change depending on the pattern of the image), you can adjust the composite channel or monochrome channel separately, or you can adjust several monochrome channels simultaneously (such as "RG", which means the red channel and green channel). The method is to hold down the SHIFT key and select the channel in the Channel floating window. Once selected, the Channel option bar will display abbreviations for the selected channel, such as RGB, RG, GB or CMYK, CM, CK, and so on.

2, the image of the color map.

The color order is distinguished by the number of pixels at each luminance value (0~255) in the image. The White triangle slider on the right controls the dark part of the image, the Black triangle slider on the left controls the light-colored part of the image, and the middle gray triangle slider controls the middle color of the image.

Move the slider to turn the darkest and brightest pixels in the channel (the selected channel) to black and white respectively, to adjust the tonal range of the image--so you can use it to adjust the contrast of the image: The left slider adjusts the contrast of the dark part of the image, and the white triangle on the right adjusts the contrast of the darker part of the image. The Black slider on the left shifts to the right, the image becomes darker, the contrast weakens (the white slider on the right moves to the left, the image is lighter and the contrast weakens). Each of the two sliders at the ends of the color graph represents the light and dark parts.

As for the Gray Triangle slider in the middle, it controls the gamma value, while gamma also measures the contrast of the intermediate tone of the image. Changing the gamma value can change the brightness value of the middle of the image, but it will not have much effect on the dark part or the light part. Move the gray triangle slider slightly to the right, making the midtones darker, and the right slightly moving to make the midtones lighter. (The data in the input Levels dialog box represents the value of the midtones)

Let's take a look at the image (Figure 5), notice the Channel option bar (for R Channel), the Triangle slider position of the color map, and the difference between the leaf and the leaf in Figure 2.

(Figure 5)

3, Input levels

I don't know if you noticed: when the slider of the color order is moving, the three value boxes of the Input levels are changed in different ways.

In fact, this control is "input levels". You can enter numerical control directly in the input box, or you can use the Triangle slider of the color order to control.

You can use these two methods to reset the high light and dark parts of the image. However, there may be a contrast problem after resetting the light and dark parts (usually the average tonal image does not have this problem, if the pixel values are set at both ends of the gray value, the midtones are problematic, and you need to adjust the contrast by using the gray Triangle slider in the middle.

4, Output levels

Output levels is located below the color map, with two numeric input boxes next to it.

He shows the values to be output, as well as the input levels: either numerically or with the slider control (but he only has two sliders: one is black and one is white). The Black triangle slider controls the contrast of the dark part of the image (the data in the first data box from left to right is the value of the dark part), and the White Triangle slider controls the contrast of the light part of the image (the value in the second data box). For example, if you move the White triangle slider to 158, the light pixel (255 in the input level) becomes 158, a pixel with a lower brightness value in the image changes to a darker pixel or moves the Black Triangle slider to 89, and the Dark pixel (0 in the input level) is mapped to 89. Other pixels in the image become the corresponding lighter pixels.

Take a look at Figure 6, and note the values in the figure, the position of the slider, and the changes in the image.

(Figure 6)

Then it should be a few buttons on the right side of the dialog box ...

OK, Cancel, Load, save these four options how to use, I believe I said it? I just say auto (auto) this option--

The Auto option acts as the auto levels directive. Click on him, and Photoshop5.5 will automatically perform an equal amount of "levels" adjustments: the lightest pixel is defined as white, the darkest pixel is black, and the pixel value of the middle color is proportionally assigned (by default, 10% pixels are reduced by 0.5% pixels, respectively, when the brightest and darkest pixels in the image are identified. To ensure that white and black values are representative pixel values.

And then there's the default, which naturally changes the default value: Press the ALT key and click the Auto button in the dialog box (Auto will become option once the ALT key is pressed), and the Option dialog box (Figure 7) is available. Enter the percentage you think fit (range is 0.5%~1%), "OK" OK.

(Figure 7)

In general, auto (automatic color level) is suitable for simple grayscale and pixel-averaged images. If it is a complex image, manual adjustment can achieve more accurate results-oh, steal a little lazy, "automatic color level" also said together, will not see it?

Finally, "OK"! On the line.

(now it's going to be a new image ...) Reopen the Levels dialog box, and you'll see the new color map ... ）