Julio Fernandez , Jun 16, 2002; 09:00 a.m.
Richard: The film processing cookbook is right. When you add water to Sodium Hydroxide a considerable amount of heat is released which can cause the mixture to splatter, shatter the container, etc., Considering that this is an extremely corrosive material specially to the eyes, the consequences can be serious. In a chemical lab, NaOH is handled with extreme care, goggles and gloves being mandatory. If neither of your books mention this, the error of omission is unforgivable and irresponsible. Even fairly dilute solutions of NaOH can cause loss of an eye even in short exposures BEWARE! It is good practice besides to always add powder to liquid to avoid lumps. Stay safe, you were smart in asking.