Introduction
In the process of shooting and producing 4K ultra-high-definition TV programs, in order to obtain richer colors and larger dynamic ranges, shooting and post-production teams often use Raw or Log format to record files.
However, the imaging devices of photographic equipment from different manufacturers have different photoelectric conversion characteristics, and their recording modes are diverse and there are different Log curves, so the images taken often have different color gamuts [1].
In this case, it is necessary to colorize the 4K ultra-high-definition TV programs to ensure the broadcast and viewing effect of the program. This article mainly discusses the picture color adjustment technology of 4K Ultra HD TV programs.
1.Overview of 4K Ultra HD TV
1.1 Related Definitions
4K Ultra High Definition (UHD) TV refers to a TV device with a resolution of at least 3,840×2 160 pixels, and its pixel density is 4 times that of traditional 1080p HD TVs. This advanced display technology can provide a more delicate and clear picture, making the colors clearer, the contrast higher, and the image details richer.
4K TV sets a new standard in improving the visual experience, especially on large-screen TVs, viewers can feel more immersive and realistic viewing effects. With the continuous progress of content production and transmission technology, 4K ultra-high-definition TV has become the first choice for consumers to pursue a high-quality home theater experience.
1.2 Features of 4K Ultra HD TV
The core of 4K ultra-high-definition TV technology lies in its excellent resolution ability. The display resolution of 3 840×2 160 pixels is 4 times that of Full HD 1 080p resolution. This resolution improvement brings higher pixel density, greatly enhances the clarity and detail reproduction of the image. Even in the large screen display, the sharpness and depth of the image can be maintained, almost eliminating the pixel grain under the retina resolution limit.
4K TVs usually adopt High Dynamic Range (HDR) technology, which not only improves the brightness peak of the display device, but also expands the dynamic range of color and brightness, achieving higher contrast and wider color gamut coverage. HDR technology optimizes the dark details and highlight details of the picture through the dynamic processing of metadata, so that the image can retain more information and a sense of hierarchy in high-contrast scenes.
Most 4K ultra-high-definition TVs apply Organic Light-Emitting Diode (OLED) technology, which has been significantly improved in terms of color accuracy and viewing angle dependence. OLED can achieve pure black display and wider viewing angle without backlight through self-luminous characteristics.
In terms of intelligence, 4K TV integrates advanced operating systems and supports a variety of streaming protocols and encoding and decoding standards, such as High Efficiency Video Coding (HEVC) to ensure efficient transmission and compatibility of 4K content. The intelligent platform provides personalized content recommendations, cloud service synchronization and seamless connection with smart home ecology, which improves users’ interactive experience and convenience.
2.The significance of color adjustment of 4K ultra-high-definition TV programs
Color adjustment is an important part of the production process of image video programs, which can be divided into two types: technical color adjustment and artistic color adjustment.
Technical color adjustment belongs to the category of production, which adjusts the image from the technical indicators to make the image present the correct light and color effect and improve the comfort of the human eye [2].
Artistic color adjustment belongs to the category of creation. In addition to mastering image technology, the operator must also have artistic aesthetics to give aesthetic connotation to image display. Artistic color adjustment is subjective and difficult to quantify, while technical color adjustment is universal and can be widely applied to most color adjustment work. This article mainly analyzes technical color adjustment.
2.1 Enhance visual impact
In the production process of 4K Ultra HD TV programs, picture color adjustment is a crucial part. Through professional color grading technology, the colorist can accurately adjust the brightness, contrast and saturation of the color, making the color more vivid and layered.
This adjustment is particularly important for delicate images with 4K resolution, because it can make full use of the advantages of high pixel density of 4K TV and greatly enhance the visual impact of the image.
The depth and richness of color have been significantly improved, so that each frame can be presented in a more vivid and realistic way, so as to attract the attention of the audience and improve the overall viewing experience.
2.2 Enhance emotional expression
In the post-production of 4K ultra-high-definition TV programs, picture color adjustment work such as color grading and color correction can not only improve the visual impact, but also help shape the emotional atmosphere and enhance emotional expression. Through the fine regulation of parameters such as color temperature, tone, saturation and brightness, the colorist can guide the audience’s emotional input.
For example, warm tones can create a sense of closeness and comfort, while cold tones can convey loneliness or melancholy. The adjustment of color contrast can strengthen the visual dynamics and further deepen the intensity of emotions.
In the wide color gamut and high-resolution picture of 4K ultra-high definition, delicate color changes can more meticulously express the director’s artistic intention, making emotional expression more accurate, and providing an immersive emotional experience space for the audience.
2.3 Unify the visual style
In the color management of 4K Ultra HD TV programs, it is crucial to maintain a consistent visual style. In the process of color grading, the color coherence of the picture can be ensured through the comprehensive adjustment of the tone curve, hue, saturation and brightness.
This kind of coherence is crucial to building the brand recognition and artistic expression of the program. Under the fine image quality of 4K resolution, the control of color consistency tests the professional skills of the colorist, because any small color deviation will be amplified in high-definition display.
Through precise color correction, it can not only ensure the uniformity of the visual style, but also improve the overall visual texture, so that the program visually presents a professional and high-quality feeling.
2.4 Improve the sense of hierarchy of details
In the color adjustment of 4K ultra-high-definition TV programs, the optimization of dynamic range is a key step, involving the fine processing of the light and dark parts of the picture. By using advanced color grading technologies, such as local color scale adjustment and highlight/shadow recovery, the colorist can enhance the detail level of the picture, so that the detail information that may have been lost can be retained and highlighted.
Under the delicate image quality of 4K resolution, this adjustment is particularly important, because it can make full use of the details brought by high pixel density and improve the depth and three-dimensionality of the picture. By accurately controlling the color dynamic range, more realistic lighting effects and visual impact can be achieved, bringing a richer and more attractive visual experience to the audience.
2.5 Adapt to different display devices
With the continuous development of science and technology, the types of display devices that can play 4K ultra-high-definition images are becoming more and more diverse, and the types of display panels are becoming more and more diverse. Through precise mapping of color gamut and Gamma Correction, the colorist ensures that the program can present consistent color effects on various models of 4K TVs.
This process involves converting different color configuration files and performing device calibration to adapt to the characteristics of various display technologies, such as Liquid Crystal Display (LCD) and OLED.
3.Color adjustment technology and application
3.1 HDR color adjustment and application
HDR color adjustment, also known as high dynamic range color adjustment, is an advanced image processing technology aimed at expanding the visual brightness and color range. In the production of 4K ultra-high-definition TV programs, HDR color adjustment realizes the seamless display of highlight details from deep dark details to bright areas by adopting wider color space and higher brightness peaks, which greatly enhances the visual impact and realism of the picture [3].
In the process of applying HDR color matching, the colorist first needs to analyze the original material, evaluate its dynamic range and color potential, and then use HDR tools in professional color matching software, such as tone mapping and color gamut ma ping), adjust the picture. Tone mapping can adjust the brightness level without losing the details of the picture, so that the highlight and shadows can be accurately displayed on the 4K display.
Different HDR standards need to be considered in the HDR color adjustment process, such as HDR10, HDR10+, HLG (Hybrid Log-Gamma) and Dolby Vision. These standards define different brightness levels and color metadata, and colorists need to optimize the content according to the specific HDR format of the target release platform.
3.2 Da Vinci Coloring System and Application
DaVinci Resolve Color Grading is a post-production software that integrates advanced color adjustment functions, which is widely used in the film, TV programs and advertising industries. The system is known for its powerful color control capabilities, precise color adjustment tools and flexible workflows, which is especially suitable for handling complex color adjustment needs of 4K ultra-high-definition content [4].
At the technical level, Da Vinci Color Tuing System provides a series of professional tools, such as three-way color wheel, RGB mixer, curve adjuster, qualitative and quantitative color selector, and advanced node workflow. These tools allow colorists to perform fine color correction, from basic color temperature adjustment to complex visual effect creation.
The node workflow is the core feature of the Da Vinci system, which allows the colorist to build complex color adjustment paths. Each node can contain a series of color adjustment operations to achieve a nonlinear color adjustment process.
At the application level, the use of the Da Vinci color system begins with the import of the original picture, followed by a preliminary color balance to ensure the consistency of the picture on different devices. After that, the colorist should use the color management function in the system to adapt different color gamuts, such as Rec.709, Rec.2020, DCI-P3, etc., to ensure accurate color reproduction.
In the creative color adjustment stage, the colorist can create a specific visual style or emotional atmosphere through the creative LUTs or manual adjustment tools provided by the system [5].
3.3 Gamma correction and application
Gamma correction is the process of adjusting the image output to adapt to the nonlinear response of the human eye to brightness perception. In the color adjustment of 4K Ultra HD TV programs, gamma correction ensures the continuity of picture brightness and the retention of details, especially in the middle tone area.
This technique is realized by adjusting the gamma curve. The gamma curve describes the relationship between the input value and the output value of pixel brightness. In practical applications, the colorist should use the gamma adjustment tool in the professional color adjustment software to carefully adjust the gamma curve to match the specific display standard or viewing environment.
4.Conclusion
In the post-production of 4K ultra-high-definition TV programs, picture color adjustment is an important task, which directly affects the audience’s viewing experience.
The colorist should adopt HDR color matching, Da Vinci color matching system, gamma correction and other color matching technologies to ensure that the picture matches the program and give the audience the best viewing experience and visual effects.