Demonstration of the whole process of solving chromatic aberration, color correction and color setting

In the process of retouching, color difference is a taboo problem for every photographer, especially beginners.I don’t know more in-depth color management methods, which makes the pictures exported by the computer look different on the mobile phone.

In this article, the whole process of color correction and color setting is explained in detail.

Define the concept first:

Color calibration refers to the use of color calibration instrument to correct the display.

Color setting refers to the software setting in Photoshop.

A few notes:

1、Color calibration is not once and for all. Monitors have color stability, which will gradually reduce the accuracy of color over time.. It’s just that a good monitor is more stable and can keep accurate for a longer time. Better monitors can be calibrated once every four months, while low-end monitors below 2000 may lose their accuracy in one month.

2. Not all monitors meet the color calibration requirements.The premise of color correction is that the color gamut of the screen panel must be above 95% sRGBBecause the color calibrator can only correct the color cast, there is no way to increase the color of the panel. Therefore, it is necessary for the color gamut coverage of the panel itself to meet the standard, and it is useless to correct the color if the display parameters are poor.The Delta E value of the display can not be changed from △ e < 6 to △ E≤2 through color correction.

3. Many display manufacturers say that they have factory color calibration. In fact, some manufacturers have not done factory color calibration because the time cost is too high. Basically, only a few professional monitors can do it, such as BenQ. However, including Apple, the accuracy of factory color calibration can only reach about 90%. I have measured the color space of new machines, which is generally 88% ~ 92%, and it can reach more than 98% after color calibration.

Take the Starscream color calibrator as an example to show you how to operate it. Starscream is also a relatively fast and professional color calibration instrument.

First of all, download a color correction driver software on the computer, which can be downloaded from Starscream official website. The website address is as follows:

Download the options shown below.

note:You can’t choose a dark room or a place where strong light shines directly on the screen when correcting colors. Soft natural light should be the best.

Connect the color calibrator to the host, open the driver software and activate it first.

Select "Software Activation" in the menu bar above.

The serial number is printed on the bottom of the color calibrator box, and it can be activated by inputting it.

Then start color correction, and the following interface will appear, in which the operation method is prompted, as follows:

Warm up the monitor first, and then select to calibrate the monitor.

Workflow, choosing "Progressive Assistant" is more convenient and intelligent.

If this is the first calibration, please select FullCAL.

The color temperature of the display is selected as standard or 6500K, and the gamma value is selected as 2.2.

The relationship between the input value of the image and the brightness of the display output affects the gray scale and brightness of the image displayed.

Place the color calibrator at the position indicated in the interface to ensure that it will not slide, and then click "Start color calibration".

In the process of color correction, this prompt will appear, which allows you to adjust the brightness of the display to an accurate value, the target 120 is the target accurate value, and the current value is your current brightness.

So adjust the brightness of the display until the current value is close to 120, and then click the blue "Update" button.

Wait for the color calibration of the monitor to be completed.

You can check the color space data of the display after color calibration. After color calibration, the BenQ sw270c display can reach 98% Adobe RGB.

Apple’s 16-inch notebook computer can achieve 99% P3 color gamut after color correction.

In the process of retouching, the operating space and color setting of the software are particularly critical, which will directly affect the color and image quality of the picture. Some students will encounter the situation that the color scale is broken or the color difference of the picture after export is large. This tutorial will solve this problem for everyone.

Software settings are divided into three parts.

I. ACR settings

Second, Photoshop retouching color settings

Third, Photoshop export settings

When opening a RAW file picture with ACR, there will be two options as shown in the above figure. Take the PS2021 version as an example, one at the top and one at the bottom, which we need to set.

Look at the options above first.There is a key parameter, that is, the cache location, which directly affects the synthesis operation in ACR. ACR can perform exposure synthesis and panoramic splicing, and sometimes when using ACR to synthesize, the temporary storage disk is full, and retouching can’t go on, which is the problem here. So you should choose a location with more space for caching. It is best to set the cache space above 50G.

In the bottom option,There are three key settings:

Color space, color depth, resolution.

Let’s talk about it one by one.

1. Color space

Color space is divided into:

Standard RGB  (sRGB)

Adobe RGB  (aRGB)

Prophoto RGB

Prophoto RGB has the widest color gamut, but it is rare, and our display has no description suitable for Prophoto RGB, so it is generally not considered; SRGB has the narrowest color gamut and is generally used for Internet image preview. Adobe RGB has a wider color coverage than sRGB.Adobe RGB or Prophoto RGB color gamut are generally used for later retouching.It is because the wide color gamut can cover more color ranges, which is closer to the color information of RAW format in the camera and avoids losing the color of the original film in the later retouching.

2. Color depth

The setting of "color depth" is divided into 8 bits and 16 bits, which actually means the number of color types of the image.The more kinds of colors there are, the more delicate the colors are. This setting can be used to prevent image color fault, because the reason of color fault is that the color you repaired is too large in the later stage, so that the color you repaired cannot be displayed.If you choose a color depth of 16 bits, you can display more colors, and it is not easy to have color faults.

This is a quadratic relationship, and the 8-bit channel is the 8 th power of 2, which is equal to 256; Here, each primary color can be divided into 256 colors, and there are three primary colors, which is 256 times 256 times 256, which is about 17 million colors. A 16-bit channel is 2 to the 16th power. Similarly, after multiplying the three primary colors, there are hundreds of millions of colors.

The parameters on the display are actually based on this setting. The color depth of the display determines the smoothness of the color transition of the display, which is generally expressed by the number of bits. Simply put, the higher the bit value of the display panel, the more gray scale levels, the more colors that can be represented and the more uniform color transition.

The 8-bit color depth display is only enough for daily office use, photography retouching requires high color, and the color depth of the material photographed by the camera is mostly 10-bit upward, so the 8-bit display is not enough. My BenQ SW270C monitor can reach. 10 bit color depth,1.07 billion colors, which can show more colors, more delicate and smoother color transition.

3. Resolution

In the process of retouching, the resolution should not be too high, because the greater the resolution, the more space the picture takes up, which will seriously affect the processing speed. Therefore, it is good to have a moderate resolution when retouching. Usually, I choose a resolution of 300, which is enough for sharing pictures on the network and printing below 20 inches. If you need to print photos with larger formats, you can change the higher resolution before exporting.

After entering the Photoshop interface from ACR, inThere is an option of "color setting" in the top menu bar "Edit", as shown below:

Select "Custom" in the red box in the upper left corner of the above picture., so that the following data settings will be applied. Many beginners use "Japanese General Use", which is a self-contained color preset, so no matter how you set the following data, it will not work.

Adobe RGB 1998 is usually selected as RGB color space.In this way, you can get enough color gamut when retouching, or you can set Prophoto RGB, but the display only has Adobe RGB color gamut.As for the color difference when exporting pictures, we set it when exporting.

Color management schemes all choose "Convert to Work"In this way, the images will be converted according to the settings in PS, reaching our unified standard. If "Keep Embedded" is selected, it will still be the information of the image itself, which will not play the role of PS.

When exporting, you can reduce the color difference of the picture through the following settings. After entering the Photoshop interface from ACR, there is an option of "convert configuration file" in the top menu bar "Edit", as shown below:

Click Color Profile to open the following interface.

Select "RGB" and choose "sRGB1966-2.1" as the profile shown above. Check this option every time before exporting pictures. If the conversion is successful, when you save the picture, there will be the following display:

When saving photos, this option will be displayed, which is the configuration file you converted before. Be sure to check it.Windows system is "reserved ICC file". Only in this way can the color information be stored in the picture, and other people’s mobile phones or computers can recognize and display the color correctly. If it is printed, professional printers will also recognize this data.

This is my BenQ SW270c monitor, equipped with flocking hood and OSD controller.

This is the standard OSD controller, which is used to set quick adjustment items, such as display color mode switching, black-and-white switching, dual RGB mode and so on, as well as quick brightness adjustment and contrast adjustment.

I use Apple’s Macbook Pro as an external monitor. I usually take my laptop when I go out and connect the monitor when I go home. Because the 16-inch laptop screen is too eye-catching for a long time, I need a bigger monitor to repair pictures at home.