Type of Developer

dry powder

water soluble

water suspendable

non-aqueous

special application

low cost, less sensitive and easy to apply

white, fluffy powders

powder only adhere to areas where trapped penetrant has wet the surface of the part

does not provide a uniform white background

indications tend to stay bright and sharp

consist of a group of chemicals that are dissolved in water and form a developer layer when the water is evaporated away.

best method is spraying, others like dipping, pouring, or brushing

the applied part can be dry or wet

the applied part must be wet or electrostatically charged

drying process is needed ( warm air dryer 21C)

Aqueous developers contain wetting agents which can lead to additional removal of entrapped penetrant.

need to dry quickly to avoid blurred and indistinct

Properly developed parts will have an even, pale white coating over the entire surface.

require frequent stirring or agitation to keep the particles from settling out of suspension

the applied parts are same manner as water soluble

drying is need as water soluble

surface will have slightly translucent white coating.

consist of insoluble developer particles suspended in water.

consists developer that suspended in a volatile solvent

normally applied by using spray gun

commonly distributed in aerosol spray cans for portability.

tends to pull penetrant from the indications by solvent action.

volatile so no need to force drying

applied to a thoroughly dried part to form a slightly translucent white coating

Example: plastic or lacquer developer

for permanent record