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The surface chemistry of photographic film materials can be complicated and thus prone to a range of manufacturing issues.
Identifying the cause, usually on small surface defects or using insufficient surface chemical characteristics, often needs sensitive molecular specific analytical tools with high spatial resolution.
Advanced surface analysis methods like Dynamic Secondary Ion Mass Spectrometry (DSIMS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and X-ray Photoelectron Spectroscopy (XPS) are capable of providing such types of data.
The following case study demonstrates how CERAM has helped manufacturers to resolve existing processes and boost research and development efforts.
Case Study - The Uniformity of Gelatin-Coated Photographic Paper
A study was conducted to analyze the distribution of gelatin on the polyethylene layer of laminated photographic paper. Secondary ion mass spectrometry imaging was used to examine four gelatin-coated matt paper samples. These samples had decreasing surface roughness graded in the order A to D. The distributions of the species were evaluated by monitoring the CN– and CH– signals that are characteristic of protein-based gelatin and polyethylene, respectively in the image acquisitions.
Analysis of Results
The outcomes clearly showed that the gelatin coverage of the paper surface increases with decreasing surface roughness. There was evidence of 1 to 10 µm-sized exposed areas of polyethylene on samples B, C, and D with some considerably larger exposed areas on A.
This result was completely consistent with the gelatin “coatability” model proposed by the photographic paper manufacturer, wherein the roughest surfaces have extreme height areas uncoated by gelatin.
As the paper’s roughness decreased, the incidence of exposed areas also decreased. It was thus concluded that this gelatin filled-in the “valley” areas in the paper structure.