Select uniform cotton samples with consistent quality, moisture content, and density. Choose defect-free Cotton Bale Wrap Film matching actual packaging specifications. Gather testing equipment including air permeability tester, sample holder, and balance. Condition all samples in a controlled environment to eliminate external variables.

Place cotton sample in holder with even packing (no gaps/compression). Measure air flow rate under set pressure using permeability tester. Record as baseline. Repeat with multiple samples to confirm data consistency. This establishes the reference air permeability for unwrapped cotton.

Wrap identical cotton samples with film at standard packaging tightness. Ensure complete coverage of air-exposed surfaces. Secure in holder and test under identical pressure conditions. Record air flow rates and repeat with multiple samples to ensure reliability. Maintain consistency in wrapping technique across tests.

Compare air permeability rates between wrapped and unwrapped samples. Significant reductions indicate restrictive film effects. Analyze correlation between film properties (thickness, porosity) and permeability changes. Determine acceptable balance between protection and airflow for optimal cotton preservation during storage/transport.