Tests on Liquid Penetrant products normally utilized in the temperature range $10^{circ}C;to;40^{circ}C$ have shown that the required sensibility can not be obtained at temperatures lower than $10^{circ}C$ with the penetration and development time usually specified in the operating procedures. It is thus confirmed that $10^{circ}C$ is the lowest allowable temperature for use of these products. The results obtained with a penetrant and develope. specially formulated for low temperatures (SHERWIN B 305+D100) are satisfactory between $0^{circ}C;and;15^{circ}C$.