Answer :
Answer:
The material must be absorptive, to perform blotting action
It must have a fine texture but not be too fine, as this may block imperfections
For colour contrast penetrants it must mask out background contours and colours
It must be easily and evenly applicable
It must form a light and even coat
There must be no fluorescing of the developer when used with fluorescent penetrant
The penetrant bleeding from a discontinuity must easily wet the material
When used with a colour contrast penetrant it must be of a highly contrasting colour. It seems agreed that the best colour is white
It must be readily removable after the test is completed
It must be non-toxic and non-irritant