Attn CBH, One thing you didnt specify was the diameter of these rings. We have also made this 'defect' while vacuum laminating Vacrel. We have narrowed it down to pin holes in the mask itself, possibly from the manufacturer but most likely they were caused by your handling process. If while handling you so much as "crinkle" or 'pinch" the material you are likely to cause damage to the emulsion in that area and this ' fisheye' will occur. Brett *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************