Printing related terminology explanation (3)

Grayscale Scanner 2.2 or lower
24bits color scanner 2.8--3.2
36bits color scanner 3.4--3.9
Table roller 3.4--4.0
High-order roller 3.6--4.5
Optical Resolution

The optical resolution is the optical resolution of the device and represents the magnification of the scan.
For example, when using a 600dpi flatbed scanner for a 300dpi scan job,
The image can be zoomed in twice (600/300 = 2 times).

A 4000dpi roller scanner can scan an image 13.3 times (4000/300=13.3).
Up to 33x magnification for 10,000dpi Desktop Scanner TopScan 10,000
(10000/300=33.3), the details of each department are still kept clear.

The general optical resolution represents the scanner's true scan resolution capability.
Some platform scanners use an interpolation algorithm to increase the resolution and cannot be used as a printing standard.
Electronic color separation

1. Electronic separation is a proper noun used in the publishing industry. In fact, it is electronic scanning.
In other words, electronic color separation means that the original document (positive film, negative film, etc.)
Photographs, print catalogues, etc. are reflective drafts), through the electronic color separation machine
(is a professional electronic scanner) to convert digital images used by computers,
That is, the separation of digital images into RGB three-color or CMYK four-color color.

2. To complete a successful electronic separation manuscript, in addition to having good hardware and software equipment,
More important is the staff's operating procedures and precautions.

3. For the electronic color separation scanning, some ideas must be explained here.
In the specifications of electronic color separation scanners, the scanning resolution is of course as high as possible.
But more important is the specification of Optical Density.
The greater the range of scan density values ​​(minimum 0 and maximum 4),
The larger the range of color classes that can be scanned on behalf of the scanner, the higher the image resolution quality.
(This specification is only marked on professional-grade drum scanners. It is generally 0--3.

4. The general optical resolution of the platform scanner is mostly 600 DPI.
Professional grade drum scanners are mostly above 4000DPI.
Maximum output resolution in general commercial platform scanner specifications (up to 4800 DPI or more)
Are all simulated using scanner software,
Therefore, the digital image quality obtained by scanning with a flatbed scanner will be worse than that of a professional drum scanner.
As for which scanner to use, it depends on your needs.
The higher scanning resolution of the scanner does not mean that the quality it scans can be better;
It means that the scanner can enlarge the magnification of the original image.
Image Scanning

1. Image scanning is the most difficult project in the entire prepress operation.
The reason is that it depends on the precision and color capture capabilities of the scanning instrument.
There is also a need for high-quality career knowledge to make correct color corrections.
To get accurate and vivid full-color images.

2. For high quality full-color magazines and professional artists,
The original (photo, print or print,
When sending to a professional electronic color separation factory, instead of using two or three million yuan high-resolution large-size roller scanners (commonly known as electric extensions), it is a good choice to scan originals into electronic map files.
Only in terms of timeliness and cost (scanning fee plus delivery costs for manuscripts),
Not very cost-effective, limited to a small amount of artwork.
Another option is to purchase a desktop roller scanner to solve a large number of artwork scanning needs.
Usually the high-end desktop roller scanner (10,000 dpi) is very close to the level of the extension.
It can meet the quality requirements of the most demanding jewellery magazines and professional poster export centers.

3. As for the 4000--5000 dpi roller scanner is often used in small output centers and magazine publishers.

4. Advertising companies or design studios can use 36-bits of platform or slide scanners to handle scans of low-magnitude ordinary documents.

5. As for 24-3Obit platform scanners are generally used to create web pages or simple business documents.
Some people also use the scanned image file to load the typesetting software to do the layout and show the sample to the customer.
Wait until the real print or send the original to the branch factory for color separation and small version.

Image enhancement
1. General scanning and digital cameras due to low optical density
Therefore, the scanned image files are often not on the level of sharpness and brightness contrast, and sometimes the gap is far.
One of the main functions of image editing software Photoshop is to gradually adjust the brightness distribution curve of the image file and trim the contrast between light and shade and the middle tone.
Eliminate color cast and enhance sharpness.

2. In general, it takes about a dozen steps to complete a complete video finishing operation.
It is a difficult task.

3. Any computer user today, whether using any brand of scanner or digital camera,
Can complete the most professional image enhancement operations by one action;
It can even be magical, and the image on the original medium-quality Photo CD disc can be instantly trimmed to a high-level work that is unbreakable in terms of sharpness and bright contrast.
Scanner Model Dynamic Range