The present invention is directed to the preparation of photoresist polymers via living free radical polymerization techniques. A catalyst for production of a polyester, characterized by comprising at least a Group 4A compound ), a compound of at least one element selected from the group consisting of magnesium, calcium and zinc ) and an oxygen-containing organic solvent. The methods further disclose acquiring the leading edge of the media being stripped and then using the beam strength of the media to assist in stripping the body of the sheet. Sealing pressure against the preloaded flexible seal from a high pressure region maintains the seal between the sealing surfaces of the support ring and segments.