A digital-to-analog converter and method for transforming a digital value into an analog signal are disclosed. The process according to the invention characterized in that the starting material is exposed to a steam treatment prior to cooking and that the pulp obtained by cooking is subjected to cold caustic extraction in the course of further processing. This may be the same beam but directed in a different direction, or two separate beams, and the switching of direction is synchronized to occur as one product irradiation is completed and the second comes into position. If one or more of the set of rules are satisfied, input data indicative of a plurality of client processing parameters is received.