Leucocrystal Violet reacts with the heme-group in blood to give a violet
color. Its application can be used to identify bloodstains that are not
visible and to enhance and provide additional contrast to bloodstain
patterns that are visible. This reagent contains hydrogen peroxide, so
if used on heavy bloodstains foaming and may result and cause loss of
detail. Leucocrystal violet is typically used on porous surfaces.