Dear Ellison,
If you do not find out what it is send a sheet back to us, complete with the batch number etc, it does help a bit if you have an electron scanning microscope to examine any defect,I have checked any QC's on Sheet film and we have none outstanding on any DELTA historical batch. The strange thing is that they all have it, if it was a coating line 99.98% it would have been found and cut out completely, and if it did get through QC the sheets are cut across the web so you would be extemely unlucky to have one ( line ) in a box never mind all of them marked. So its a strange one, I will keep my eye on the thread.
Regards
Simon ILFORD Photo / HARMAN technology Limited :