Digital Photography Technology in Printing Application

Foreword

The content of the image form is an important reproduction target in the printing media. In the past, the images recorded by the silver salt material were mostly converted into a digital file by the scanning method, and then integrated into a part of the print by the typesetting work. Recently, the technology of digital photography has gradually matured, and the way of directly shooting electronic manuscript manuscripts has become increasingly popular. Basic principles, operating characteristics, equipment status, application practices and future directions are briefly introduced in this article.

Basic principles

Digital image processing is no stranger to the digital printing environment. Adobe Photoshop-like image editing processing software has become one of the standards for prepress operations. However, the basic concept is to obtain images using a scanner or to obtain images with a digital camera. There are some differences and similarities that need to be explained.
Like the scanner, the digital camera uses the focus of the optical lens to project the image on the photo-electric sensor assembly to form an image pixel unit (Pixel). However, the light source of the scanner is fixed, and the object to be scanned is generally in the form of a plane; however, the object shot by the digital camera may be in a three-dimensional form. The intensity of the light source in the scene and the characteristics of the color temperature may vary, and the relative complexity is many, and special attention must be paid in use. .

Comparing with the production process, when film is used to record images and prints are printed, signal loss will occur at different levels in film exposure and chemical processing, and the digital camera directly shoots to generate electronic files. The process has only one loss! Therefore, from the aspect of the distortion rate of the signal, the digital camera can directly take pictures to have a better image quality, and at the same time, it can immediately shoot and improve the time efficiency.

However, the image quality obtained by today's digital cameras is not necessarily better than the image quality obtained by scanning the film. There are many reasons, such as the optical quality of the lens, the quality of the CCD, the capability of the software, or the cost-effectiveness. However, the analysis is based on the principle. The space is quite large and has great potential.

Operating characteristics

Generally speaking, when the scanner is operated, the size between the original and the copied product is used as a reference for calculating the magnification. Therefore, it is not necessary to distinguish the pixel from the pixel, but it is necessary to use the digital camera to capture an image. Pay special attention to this relationship.

The pixel is generally a parsing unit when the input device samples a video light source. For example, the overall sampling capability of the digital camera is a pixel unit. The mass point is the individual imaging entity unit that the hard device can control, such as how many dots of ink in the unit of the printer can control the resolution as the unit of measurement (dpi), and how many dpi the laser screen output machine also The number of printed lines can be simulated as a specification.
In use, the general principle is to infer the size of the input image file that can be rendered by the resolution of the output device. For example, for a print product with 150 lines, the pixel amount of the digital camera is used to remove the pixel amount of the digital camera and the printable value can be calculated. size of. For a 6 million pixel (3000 x 2000) camera, a 10 x 6.6 inch image size can be printed. This conversion principle is defined by the fixed file size, relative to the available size under different resolutions, that is, the principle of conservation of data proposed by the author. The practicality still involves the image quality coefficient and other characteristics, which are more complex. Interested readers can read the book "Digital Photography Technology" for details, or refer to the website http://.

The current situation of digital cameras is amazing and the price adjustment is quite attractive to photography enthusiasts. However, there are several phenomena that require special attention. It is generally believed that the higher the pixel value, the better the image quality. In fact, this is not true because the resolution has the resolution of the optical resolution and the electronic resolution. The latter is obtained by the mathematical operation of the former and is a virtual number. At the same optical resolution, the actual image quality is the real focus. This involves the quality of the lens, the amount of photoconductor noise, and the software processing capabilities. It is rather complicated, but the best The method is to actually shoot to comment.

The current digital cameras are broadly divided into three categories, ranging from tens of thousands of yuan, from several tens of thousands of yuan to nearly three million. The common point-and-shoot digital camera is more than a few million dollars. It is more than enough to take photos of everyday photos or web pages. Recently, the interchangeable lens type digital camera developed by the old monocular camera system is a favorite of news reporters or professional photographers, because the old lens and other devices are compatible with the system, and the monocular camera has the flexibility and maneuverability. The functions are all available, almost the same as using the original high-end single-lens camera. The only drawback is that there is still the problem of lens magnification, which is very painful when shooting at wide angle, but the improved models will soon be available! The system equipped with a digital camera with a large camera is a powerful tool for commercial photography. Because of its large file size, it can also control perspective angles such as tilting, but the price is close to one million and the economic threshold is high.
Application Practice

From the first generation of digital cameras to 20 years of history, digital cameras can be seen everywhere on the street. There are professional applications in mail order catalogs and wedding photography in China. News reporters are almost a digital camera. But does it mean that image quality is improved at the same time?

In previous printing processes, physical photos and slides in a standard environment served as the basis for photographers to make layout edits and communicate with prepress workers. However, in the process of digital photography, only actual image files were used as communication and The originals are made, but each computer screen has its own color characteristics, and there is a gap in the images that are presented. Therefore, digital proofing or color management systems become important cooperation items. At the same time, previous photographers only operated cameras, and now they also need to operate computer equipment. These additional technical costs and capacity requirements are not very explicit factors, and special attention should be paid in application.

Future outlook

The timeliness and convenience of digital photography are its irreplaceable advantages. However, at present, the image quality and economic benefits are still rising rapidly. The new digital cameras will surely become a part of the electronics industry in Taiwan and become scanned. Machine-like popularity. For the printing industry, the image produced by digital photography will become a very common type of manuscript in the future. How to adjust the printing workflow to match this trend and how to learn the technology to respond to it will be a key point worth investing in!

Source: CA800 Search