Offset product quality testing requirements and data usage (on)

1. Observe the ambient color around the surface: N6-N8, C (0.3. If the wall and ground around the observation surface do not meet the above requirements, apply a baffle that meets the above requirements to enclose the sample or use environmental reflections. Light produces less than 100 lux of illumination at the viewing surface.

The background of the observation reflection should be N5-N7, C<0.3; for the occasion with high color matching, C<0.2.

2. Detect dust and clean working environment.

3, operating temperature requirements

Temperature is 23°C±5°C Relative humidity is 60+15(-10)%

4, lighting conditions

1 Observe the transmission sample

The light source is a simulated body of CIE standard illumination body D50 (a typical crucible with a correlated color temperature of 6504K, X=0.3457, Y=0.3586 on CIE1931), and the profile of the light source should not be seen on the observation surface or there is a sudden change in brightness. The uniformity of the brightness is ≥ 80%, and the color rendering index of the light source is Pa ≥ 90.

2 Observe the reflection sample

The light source is a CIE standard illumination body D65 (typical calorimetry with a correlated color temperature of 6504K, X=0.3127 on CIE1931, Y=0.3291). There should be no illuminance changes in the observation plane. The uniformity of illuminance is ≥ 80%, and the color rendering index of the light source is Ra ≥ 90.

5. Observers must be non-color blind and non-colored normal color vision observers.

Second, the observation method

1. The transmissive sample should be illuminated by inactive diffuse light from behind and viewed perpendicular to the surface of the sample. Observe that the sample should be placed in the middle of the lighting surface as much as possible, so that at least three sides have 50mm wide illuminated borders. When the total area of ​​the observed transmission sample is less than 70mm x 70mm, the width of the illuminated boundary should be reduced appropriately so that the boundary area does not exceed 4 times the area of ​​the sample, and many parts are covered with a gray opaque light blocking material.

2. When observing the reflection sample, the light source is perpendicular to the surface of the sample, and the angle of observation is at an angle of 45° with the normal to the surface of the sample. For observation conditions of 0°-45° illumination, see Figure 1. As an alternative observation condition, it is also possible to illuminate with a light source at an angle of 45[deg.] to the normal to the surface of the sample and observe the surface of the vertical sample, corresponding to a viewing condition of illumination of 45[deg.] to 0[deg.]. See Figure 2.

Third, the use of measurement and control bar

1, measurement and control principle

The increase in the area of ​​1 dot is proportional to the total length of the edge of the dot.

2 Use the same area of ​​the geometry as yin and yang to measure the shifting of control points.

3 When the pattern changes, the angle at the included angle changes significantly from the length of the arc, which plays an amplification role.

4 Measure the horizontal and vertical azimuth changes using a line of equal or unequal width.

5 Use equidistant concentric circles to measure changes in any position.

2, the use of conditions

The conditions for using the test strips are the same as the conditions for printing, proofing and printing.

3, use method

Long strips should be used and placed at the end of the sheet, parallel to the axis of the printing cylinder, in order to observe and control the uniformity of the image.

4, printing common control strip

1GATF star: Used to determine dot gain, slip, and ghost.

2GATF signal strip: used to determine dot gain and distortion.

3 Brunner signal strips: for density determination, dot gain, dot distortion.

4 high-profile network detection map: for the observation of high-profile network reproduction.

CY/T5-1999 fine print reproduction of 2% -4% dot area, the general print bright tone reproduction of 3% -5% dot area.

5GATF color signal strip: used to determine dot gain, distortion, density, and gray balance.