| *** - SOLDER MASK AND LEGEND IN DIFFERENT COLOURS |
| Solder mask colour selection based on manufacturing, inspection, optical performance and visual identification |
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| MOST COMMON COLOURS AND APPLICATIONS |
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| COLOUR | | TYPICAL USE | WHEN TO CHOOSE IT | MAIN ADVANTAGE | TECHNICAL CONSIDERATIONS | RECOMMENDED LEGEND COLOUR |
| Green |  | General production; industrial applications; high-density PCBs | When there are no specific optical or aesthetic requirements | Mature process, good AOI performance and wide availability | Shade may vary depending on material and supplier | White |
| Black |  | Consumer electronics; panels or visible PCBs | For a premium appearance, to conceal tracks or reduce reflections with a matte finish | Attractive appearance and reduced reflections | Lower contrast for inspection and rework; verify fine-feature design rules | White |
| White |  | LED lighting; luminaires; signage | When light needs to be reflected and distributed | High reflectance | May yellow with heat/UV exposure; specify reflectance and stability | Black |
| Blue |  | Product families; industrial equipment or prototypes | To distinguish variants while maintaining reasonable contrast | Clear visual identification | Confirm availability, shade and manufacturer design rules | White |
| Red |  | Prototypes; revisions; voltage or functional variants | To quickly distinguish versions during production or servicing | Strong visual differentiation | Does not replace part numbers or traceability; confirm lead time and shade | White |
| Yellow / orange |  | Product identity; special visual signalling | When highly visible differentiation is required | Immediate recognition | Less common: potentially longer lead times, higher costs and batch-to-batch variation | Black or another contrasting colour |
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| APPLICATIONS THAT MAY REQUIRE A SPECIFIC COLOUR |
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| APPLICATION | | SELECTION CRITERIA | | | | |
| LED lighting |  | White solder mask formulated for high reflectance and resistance to yellowing after reflow and ageing. | | | | |
| Visible products / consumer electronics |  | Black, brand colours or matte finishes; approve a physical sample for shade and gloss. | | | | |
| Revision and variant control |  | Red, blue or another colour by product family as a visual aid; always retain alphanumeric or 2D-code identification. | | | | |
| High-density or fine-pitch PCBs |  | Prioritise actual material capability: minimum opening, solder mask dam width and registration; green generally offers the most stable process. | | | | |
| AOI inspection and rework |  | Avoid low-contrast combinations without validating lighting, AOI settings and legend legibility. | | | | |
| Safety or servicing requirements |  | Use colour only as a secondary aid; warnings and identification must remain legible and must not rely on colour alone. | | | | |
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| PRACTICAL SPECIFICATION GUIDELINES |
| Specify in the order: colour and finish (gloss/matte), reference or approved sample if appearance is critical, legend colour, number of thermal cycles, LED reflectance requirements and material-specific DFM rules. Do not assume that every colour supports the same minimum solder mask dam or registration tolerance as green. Also validate laser or printed marking contrast and AOI readability with the final colour combination. |
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