Ⅰ. Optimize the production process to reduce defects at the source.
a. Ensure uniform dispersion of pearlescent pigments.
Pearlescent pigments (such as mica powder and titanium dioxide particles) must be pre-treated before production. High-speed mixing, grinding, or ultrasonic dispersion is required to prevent pigment agglomeration.
Adjust the raw material mixing ratio to ensure thorough integration of the pigment with the celluloid substrate (nitrocellulose, plasticizer, etc.). Use online testing equipment to monitor dispersion uniformity and adjust the mixing speed or time accordingly.
b. Stabilize processing parameters to avoid gloss variations.
During extrusion or cast molding, strictly control temperature (such as melt temperature and chill roll temperature) and pressure to prevent localized excessive temperature that could lead to pigment oxidation, or uneven pressure that could cause thickness variations across the film surface (which can directly lead to inconsistent pearlescent reflectivity).
After forming, maintain a uniform pulling speed to avoid surface stress variations caused by uneven stretching speeds, which can lead to localized dulling of the gloss.

II. Strengthen Raw Material Screening and Quality Control
a. Select pearlescent pigments with high purity and uniform particle size distribution to avoid uneven gloss on the film surface caused by uneven pigment particle size.
b. Celluloid substrates (such as nitrocellulose and plasticizers) must meet environmental standards to avoid excessive impurities (such as residual solvents and metal ions) that may cause spots or yellowing on the film surface.