Cause: Celluloid contains cellulose nitrate. Long-term exposure to alternating heat and cold (such as large fluctuations in ambient temperature) increases its brittleness, making the splices susceptible to cracking due to stress concentration (especially at the fused edges of hot-press splices). Poor compatibility between the glue and the film material (such as using non-solvent-based glue) can lead to bond failure and delamination.
Impact: Structural integrity is compromised, potentially leading to further tearing, especially in stress-bearing environments (such as furniture panels).