New to LF and trying to get film organized. Years ago I went the loose-leaf binder route for slides but now would like to use a different approach with 4x5 CTs. After researching the web, it looks like Mylar (or its current equivalent) and polyester are best, so I purchased several makers' versions of both types of clear envelopes. The clear polyester 4mil 4x5 envelopes from Hollinger Corp (Genealogical Storage Products) seem to be perfect for my needs. However, to minimize the dust problem, I would like to use another slightly larger clear poly envelope into which the CT-containing one could be slipped, head first to create a better dust seal. (I have ruled out all other non-transparent products.) These would then be stored in small portable archival boxes. More web scouring (P-File, PrintFile, Clear File, Light Impressions, University Archival/Storage Products, even office supply sites, etc, etc) but I cannot find any supplier of the 4.5 x 5.5 inch clear envelope. This 4.5 x 5.5" size would be ideal. If anyone has any ideas as to who might make/supply archival poly envelope products in off sizes, please advise. Many thanks.