Printing-related terminology interpretation (1)

1. Vector Images (Vector Images)

The vector graphics file produced by the drawing software (such as CorelDRAW!, Illustrator, Freehand),
It consists of geometric objects such as lines, ellipses, rectangles, curves, and various complicated paths.
The files are small, and they do not produce aliases when zooming. They are usually used as artwork illustrations.
The gradual change of the vector image file with different shapes (Blending)
And there is a good performance on the Color Gradient.
However, the vector image file on the control of the color order cannot catch up with the image file.
Color gradations made in CorelDRAW and Illustrator tend to exhibit distinct color bands.
However, the color gradient effect produced in Photoshop is much softer.

2. Raster Images

Image files produced by video editing software or via scanners, video discs, digital cameras, etc.
It is usually composed of an infinite number of pixels containing various grayscales or colors.
The feeling of this type of file is more real, but it usually produces a sawtooth phenomenon after it is enlarged.

3.EPS/DCS image files

Specify the EPS file format by using the [File]Save a Copy] command in Photoshop.
You can save the file as an EPS file. At this point you can further set whether or not to include the pre-view file
(1bit black and white or 8bit color). Can also set True Encoding format (ACSII or Binary)
If you save an RGB image file in EPS file in Photoshop,
You will get a single larger EPS file.
If the image is converted to CMYK mode and then stored as an EPS file,
You can further set the DCS (Desktop Color Separation) format.

When you use CorelDRAW! to do your artwork design,
The format of the EPS (Encapsulated Postscript) can be stored in the pattern or layout using the [File] Export command.
So that the file can be loaded with other software (or different operating platforms, continue to process or directly output. When the final layout is stored in EPS format, its content and color can no longer be modified (but can be enlarged or reduced).

The so-called DCS (Desktop Color Separation)
Is a professional color separation image file specially designed for QuarkXPress.
It will generate four high resolution color separations for a full color image
(CMYK four-color, and a low-resolution grayscale or color Preview image file.)
Since the DCS file is actually a set of complete EPS files consisting of five image files,
Therefore, it is also known as EPS-5 file.

When the DCS specification EPS image file is loaded in QuarkXPress,
QuarkXPress only uses true pre-view files for typesetting.
Only use its high resolution CMYK color separation image at the output, so the efficiency is greatly improved.
This is the OPDF function built into QuarkXPress. You can also use [Save Page As EPS] in QuarkXPress.
Store any completed layout full-color pages into a DCS-EPS image with pre-view files.
You can also set the zoom ratio, and then arrange the file into the layout, which is very easy to use.

4. Screen Font
Single word design theory can be divided into bitmap fonts (Bitmap)
Two kinds of outlines (Outline).

Bitmap
Bitmap fonts are like dot matrix images. They are filled with colors (usually black).
Then a number of pixel combinations are combined into text, as shown in the following figure is a black body Chinese dot matrix font.
Because dot matrix fonts are combined into a fixed graph,
Therefore, when the font is magnified, the edge will have a zigzag shape, and when it is reduced, it will be easily blurred into a ball.
So most of the systems and hardware currently used no longer use dot matrix fonts to print text.
However, the display of computer screens is still dominated by dot matrix fonts, so the text is sometimes referred to as dot matrix fonts.

Outline font (Outline)
The frame fonts currently used in computer systems are divided into TrueType and Postscript fonts.
The outline font is a frame that uses a Bezier curve to describe the font.
Because the frame glyphs use mathematical operations to describe the font frame,
Therefore, the same font can be arbitrarily enlarged, reduced, rotated, and tilted.
The following describes the TrueType and Postscript fonts.

5.TrueType
TrueType fonts are a dual screen and print font.
When you select the TrueType font, the system automatically generates a screen font display; when printing,
The system will use the graphics of the driver of the TrueType frame font.
Then send it to the printer for printing.

So, when you use a different printer or output device (indicating that the driver may be different),
The results may be printed out slightly different (of course, the error will not be too much).
TrueType fonts were originally designed for office use.
Therefore, the maximum output resolution can only reach 700 DPI.
This output resolution is very different from the commonly used 1800DPI.

However, the types of TrueType fonts are quite large (including English and Chinese) and they are quite cheap.
The most commonly used font for general computer work.
If you use Chinese TrueType fonts in vector graphics software,
Special care must be taken to ensure that the fonts used will produce "interlaced hollow phenomena" (early Wakang).
If this error occurs, it is recommended to replace the Chinese TrueType fonts used.