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 

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