Helping to produce overall cool tones, this 100mL bottle of Finisher Blue from Moersch Photochemie is a concentrated black & white paper developer additive. By adding this finisher to the developing bath, black tones will take on a decidedly colder, blue-black coloration. The strength of the effect can be varied by how much solution is added to the developer, however if more than 10mL is used per liter of developer, processing times should be increased.