Positive or negative?

This is an attempt at a comprehensive answer, but inevitably will not cover every application, and there will be specific processes and types of component that run contrary to what is suggested here. What matters is that you understand which processes have actually been used for the product that you are reverse-engineering, that you understand why those particular choices were made, and that you appreciate the consequences of those choices for manufacturability, cost, quality and reliability.

	application	positive	negative	combined	comments
semiconductors	wafer manufacture	●	●	●	as with boards, the majority of processes use negative resists, but the overall fabrication uses both subtractive and additive processes
	lead-frame manufacture	●	●		most lead-frames will be etched or stamped, but electroforming is also possible
	part coding	●	●		traditionally
components	resistor active area	●			most thick film resistor materials are printed, although trimming by laser machining is definitely subtractive!
	chip capacitor electrodes	●			electrode materials are printed – depositing expensive materials everywhere, and then removing the surplus is not economic
	part coding	●	●		parts are usually printed (pad printing is common) and only occasionally marked by laser
	lead frame manufacture		●		most lead-frames will be etched or stamped and formed
	labels	●	●		most labels are printed, but some styles (for example, anodised aluminium types) will be created by modifying an overall covering
	displays	●	●	●	displays are very varied and can be extremely complex
	hybrid microcircuits	●	●		most thick film materials are printed; the less common thin film types are usually etched patterns
PCB fab/assembly	foil patterning	●	●	●	negative resist systems are by far the most common, but board fabrication uses both subtractive and additive processes
	solder mask	●	●		printing is only used for low-definition applications; most solder mask is deposited overall (curtain-coat or film) and photomachined
	legend	●	●		most legend is still printed, but (where legend is required) there is one trend to pattern as for solder mask (negative) and an opposite trend to ink-jetting (positive)
	stencil manufacture	●	●		most stencils are laser-cut or etched, but electroforming is also used
	solder paste application	●			stencil printing and dispensing are both positive
	component gluing	●			screening and dispensing are both positive
enclosure and interface	switch legends	●	●	●	switch legends may be printed (pad printing is common) or engraved; illuminated switches are frequently both engraved (negative) and filled (positive)
	panel legend	●	●		most legend is printed or ink-jetted, but legend may be engraved or applied as a patterned overall protective film

In this table, a magenta dot indicates that the process is occasionally used, but is not the usual choice.

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