The blue color positive CTCP plate is a positive working printing plate based on traditional PS plates using computer-to-plate (CTP) technology. Its core feature is the digital imaging achieved through a specialized photosensitive coating, while also boasting a distinctive blue appearance.

Positive CTCP plates utilize a photodegradable coating. The photosensitive material in the exposed areas decomposes under the action of laser energy and is removed during development, forming the non-image areas. Unexposed areas remain, forming the printed image. Using ultraviolet light with a wavelength range of 360-450nm, the image is directly exposed on the traditional PS plate, eliminating the film output step and enabling digital platemaking. This technology maintains the efficiency of CTP while maintaining compatibility with traditional PS plates, reducing equipment upgrade costs and achieving higher sensitivity and dot reproduction accuracy. The light and dark gradations of the positive CTCP plate perfectly match the original. After exposure, the unexposed areas are dissolved by development, resulting in a printed image that is consistent with the original.

The structure of blue color positive CTCP plate:

- Aluminum Plate Treatment:

Electrolytic roughening, anodizing, and sealing treatments create a multi-layered composite grain structure, improving wear resistance and water storage capacity.

- Photosensitive Coating Formula:

Utilizes high-sensitivity resins and photoinitiators, achieve sensitivity of 80-100 mj/cm², supporting 2-98% dot reproduction at 300 lpi resolution.

- Blue Appearance:

The blue color typically results from the oxidation of the aluminum plate or specific additives in the coating. For example, some manufacturers use an anodizing process to create a blue color on the plate, enhancing its surface hydrophilicity and making it easier to distinguish between different plate types. The blue coating may also possess specific spectral absorption properties compatible with the light source used in UV-CTP equipment (e.g., 360-450nm UV light).

Key advantages of blue color CTCP positive plate:

1. Platemaking efficiency and quality

- Photosensitive speed:

Mainstream products utilize wavelengths of 830nm (thermal) or 360-450nm (UV), with exposure energies of approximately 90-120mj/cm². Platemaking speeds can reach over 20 sheets per hour.

- Dot reproduction:

At 300lpi, dot coverage of 1-99% can be achieved, meeting the demands of high-precision commercial printing. For example, the HC positive CTCP plate utilizes suspended air-conducting particle technology to effectively prevent screen voids and screen dropouts.

2. Print run and stability

- Typical print run:

Printing with standard inks can reach 80,000-100,000 prints. After baking (230-250°C for 5-8 minutes), the print run can be increased to over 200,000 prints.

- Environmental adaptability:

At a developing temperature of 22-28°C, the plate offers a wide development tolerance, allowing temperature fluctuations of ±2°C without affecting dot quality.

3. Environmental and cost advantages

- Development process:

Using an alkaline developer (such as sodium metasilicate solution), compared to negative-working plates, this eliminates the need for preheating and reduces wastewater disposal costs. Some manufacturers offer process-free versions that can be directly printed after exposure, further reducing chemical emissions.

- Compatibility:

Traditional PS plate development equipment can be used directly, reducing equipment modification costs for printing companies.

Typical application scenarios of blue color positive CTCP plate:

- For commercial and packaging printing

Blue color positive CTCP plates, with their high resolution and dot stability, are widely used in fine-print applications such as brochures, posters, and labels. For example, the CTCP plates achieves 2-98% dot reproduction at 300 lpi, making it suitable for high-end commercial color printing.

- For newspaper and book printing

Its high platemaking speed (for example, output 20 sheets per hour) and economical plate cost make it an ideal choice for web printing in the newspaper industry. Furthermore, its press run meets the high-volume demands of book and magazine printing.

Blue color positive CTCP plates occupy a key position in the offset printing industry due to their efficient platemaking, high-precision reproduction, and cost advantages. When selecting a printing plate, printing companies need to comprehensively consider equipment compatibility, printing needs, and environmental protection requirements, prioritizing products with high printing durability and wide development tolerance (such as HC's CTCP plates), and improving plate-making quality through standardized operating procedures.