Crack Check White Contrast is amongst the Best of FerroChem make Products which have no direct relevance to crack detection by MPI, but due to its unique qualities, it is used at every place where Crack Detection by MPI is practiced especially in out door applications. FerroChem White Contrast is available in Self Spray Aerosol Cans of 420 ml. Net Contents. A uniform white Coat on almost any kind of surface without pre-coat preparation can be obtained by simply spraying the contents. The coat dries off within 60 seconds hiding the non favorable background of the job. The above characteristics of Crack Check white contrast makes it the most suitable for using in combination with FerroChem Black for crack detection by MPI. Crack detection sensitivity obtained by using crack check white contrast in combination with ferrochem black is equivalent to that obtained by using FerroChem make fluorescent inks and it has an additional advantage of inspection in day light without the hassel of using special lighting arrangements.