Looking at distance printing from color quality management

Third, color quality control technology

It is mainly divided into two parts: one is the color management of general print, and the other is the color quality control in digital files. First, the general print control is introduced. The most basic printing is the issue of output gauges. Commonly used control methods include four methods: register control analysis, full plate density control, dot gain control, and gray balance control.

Another is the quality evaluation of the ICC profile color profile. When we enter an image file into the computer, the profile data generated on the computer is correct. We can use the created profile to add this image to the image. When it is added, it will have Obvious changes. (As shown in Figure 3 to Figure 7)

Figure 4 Figure 5

Figure 6 Figure 7

The Research Center has also developed compatible ICC Profile software technology that can be used to assess whether the color space is incorrect. The profile used by the inspection is not working properly. If the manufacturer needs it, it can also contact the Institute.

Next, we must remind everyone to pay attention to the importance of color quality control:

(1) The accuracy and stability are the prerequisites for selecting a digital proofing system in the market; if it is not possible to meet these two requirements, it is not a reliable digital proofing system.

(b) The main factors affecting the digital proofing system are: printing speed, operating costs and color management.

(C) Printing Speed: In terms of speed, the market can already find a high-resolution draft proof in 10 minutes.

(D) operating costs: mainly depends on the price of ink and special paper for proofing.

(5) Color management: It depends on accuracy and stability. It is also the most important factor. Even if the speed is faster, the cost will be lower. If the printing effect cannot be accurately and steadily previewed, it may lead to incur printing on the subsequent stage. Big economic and time loss.

(6) Digital proofing color evaluation:

1. The methods used to evaluate color are:

(1) Visual Inspection - Subjective Evaluation (Color Management)

(2) Measurement - Device Calibration

2. The focus of color assessment:

(1) Single Color Block - Single Color Stimuli

(2) Measurement method - Test target test guide

(3) Complex Image - Complex Color Image

(4) Visual inspection - Standard Test Image standard proofs

3. Comparison of color assessment

Category Subjective Evaluation Objective Evaluation Method Visual Measurement Method Test Image Standard Image Test Target Test Guide Use Color Conversion Device Calibration

(7) Color difference

Finally, when we talk about color control, there is a concept that cannot be ignored because, ultimately, regardless of the manufacturer, the customer or the printer, in order to maintain the color consistency of the last thing seen, it is necessary to pay attention to the problem of color aberration.

1. Definition of Color Difference: It refers to the difference in the color of the eye when comparing two color objects, abbreviated as ΔE.

2. The commonly referred to as ΔE is the color difference formula of CIELAB uniform color space developed by CIE in 1976.

ΔE=[(L1-L2)2+(a1-a2)2+(b1-b2)2]1/2

3. In general

(1) Delta E > 6: Unacceptable, human eye can easily recognize the difference in color.

(2) Delta E <4: acceptable, human eye can identify the color difference, but it is not very obvious.

(3) Delta E <2: The human eye can hardly recognize its color difference. (Huang Minfeng)