How to Identify Color Distortion in Printing?

Posted on 04-26-2024 by

Currently, there are many color management systems in the printing industry, which provide a certain level of control over color in printing. However, the demands for color accuracy among printing customers are becoming increasingly strict. In order to provide better printing services, it is necessary to understand the main factors causing color distortion and methods to identify it.

I. Main Factors Causing Color Distortion

1. Color Reproduction Processing Causes Color Distortion

Modern printing typically uses CMYK four-color inks to reproduce colors. Due to purity issues with ink itself, color distortion can occur during the overprinting process.

2. Separation Processing Causes Color Distortion

Printing usually employs CMYK four-color inks to replicate colors, while digital capture devices capture image information in RGB format. Therefore, before printing, the image information needs to be converted to CMYK mode, known as separation processing. During separation, each pixel's color information (typically in RGB) is decomposed and converted into color information suitable for CMYK printing. This process can result in loss of color information.

3. Color Distortion in the Original Manuscript

Most printing image originals are obtained through photography. For photo originals, color distortion may occur due to improper operation during shooting or color fading of colorants used in reproducing colors. Additionally, with the increasing popularity of digital cameras, there are more digital image originals. However, due to the higher technical requirements for operators of digital cameras, images captured by inexperienced operators may suffer from problems such as dimness and blurriness, leading to color distortion in the original manuscript.

4. Scanning Processing Causes Color Distortion

The image density of photo originals is continuous, and the image information needs to be collected into a computer. When using scanning devices to scan images, the image needs to be divided into discrete pixels, and the R, G, B information of each pixel on the original manuscript needs to be collected point by point. During scanning, there may be loss of color information from pixels, and since all image processing is based on the collected image information, any color operations are limited to this information. Therefore, scanning is a crucial step in image processing, and improper operation may cause color distortion in the image.

II. How to Identify Color Distortion

After understanding the main factors causing color distortion, it is crucial to identify color distortion during the actual production process.

1. Impression Benchmark Method

Human eyes have a certain adaptability to colors. For images with slight color distortion, repeated observations may weaken the ability to identify them. Therefore, using the impression of the human eye to eliminate the limitations of human color vision is an important method for identifying color distortion.

2. Neutral Color Benchmark Method

There are many neutral colors in life, such as black, white, and gray, which serve as the zero point for colors in the colorful world. These neutral colors can be used as a benchmark for identifying color distortion.

3. Skin Color Benchmark Method

Skin color is the most familiar color to people. For images of people, especially portraits, skin color can be used as a basis for identifying color distortion. Regardless of whether it's yellow, white, or black skin, they all have a rule: they all contain a reddish hue. Therefore, if the skin color of a person in an image appears yellowish, it may give the impression of being unhealthy. Under normal circumstances, even if the skin color of a person in an image is actually yellowish, it should be adjusted to a reddish hue during color correction.

If the main factors causing distortion and the methods to identify it are mastered proficiently in printing operations, then the color accuracy in printing can be well controlled, achieving the complete effect desired by the customers. Therefore, we cannot ignore the grasp of color distortion in printing.