What is an important aspect when selecting the type of developer used in penetrant testing?

In penetrant testing, selecting the appropriate type of developer is critical for effectively revealing discontinuities in a material. The developer's primary role is to enhance the visibility of penetrant that has been absorbed into surface flaws, enabling clear detection.

Focusing on the type of discontinuity to be detected allows for the selection of a developer that best suits the specific requirements of the job. Different types of developers may be formulated to work optimally with certain materials or to enhance the visibility of penetrants in various conditions. For example, some developers may be more effective at revealing hairline cracks while others are designed to highlight larger voids. Understanding the nature of the discontinuities being inspected thus ensures that the developer chosen will provide the best results in terms of sensitivity, clarity, and overall efficacy in detecting defects.

Other factors, while important, may not directly impact the effectiveness of the developer in revealing discontinuities. Cost-effectiveness and availability might influence purchasing decisions, but they do not address the technical requirements of the test itself. The color of the developer, while it can affect visibility, does not inherently correspond to its performance in detecting specific types of discontinuities.