What should be monitored to ensure the quality of the developer used in penetrant testing?

Monitoring the water ratio in the developer is critical in penetrant testing because this affects the concentration and effectiveness of the developer solution. The proper water-to-developer ratio ensures that the developer properly penetrates the surface and enhances the visibility of defects. If the ratio is not maintained correctly, it could lead to poor quality results, resulting in undetected flaws or misleading readings during inspections.

Maintaining an appropriate water ratio also helps in prolonging the effectiveness of the developer and ensures consistent performance throughout the testing process. Other factors might impact the overall testing environment, such as the developer's weight or its color, but they do not directly affect the penetrant's ability to function as required. Therefore, focusing on the water ratio is essential for ensuring high-quality penetrant testing results.