Hi, I would like to know what is the best kind of plastic to envelope negatives for storage and preservation. Is it poliethilene? Thanks,

Sergio.

-- sergio bartelsman (sergio@bartelsman.com), May 12, 2002

Answers

Dupont Mylar D/Mellinex--uncoated polyester--is the best. You can get Mylar D products from archival vendors like Light Impressions, Gaylord, University Products, Hollinger etc....the best types of sleeves for roll film & sheets are the ones that have no adhesives or seams really...they have a crisp, fold type design that lets you insert a neg rather than sliding it in place. An interleaving sleeve is a sleeve that is just a folder. A top-load, locking sleeve or Fold-Lock (Light Impressions), is a sleeve that has a locking flap at the top. If you have to get something with a seam, look for a heat seal... Mylar D is expensive though, about 3 times the cost of other plastic sleeves.

The second best is UNCOATED polypropylene. Don't get a sleeve with any slip agents or anti-stat agents added to it. You can get uncoated polypropylene sleeves in the same designs for about half off a Mylar D sleeve. If you carefully shop around, you can also get suitable sleeves in 1000 foot rolls from lab suppliers. It's alot cheaper this way, and you can sleeve about 300+ rolls of 36 exp. 35mm like this ....otherwise you get the stuff in strips of 6 frames usually, or 4 for 120. Some manufacturers supply the material in a 36 exp strip, precut. Look for uncoated,clear & locking material.

The next in line is UNCOATED polyethylene....this is the material made in neg tubes, notebook pages and other things, but it's often not pure in these forms, so buyer beware....it can have slip agents added to the enclosure to help in manufacturing, or other things like anti-blocking or anti-static agents...sometimes there can be problems with the enclosure sticking to a neg or slide as a result...but this can happen with other plastics too if the temp & humidity & storage pressure--on the sleeve--is too high...so if you use plastic, keep the temp & rh as low as possible.... under 70 degrees F and 30-50% rh. If you can't keep it cool & dry, maybe look into paper sleeves...

Lastly, there is a polyethylene sleeve in high-density polyethylene...most of these others are low-density. The HDPE sleeve isn't clear, but is supposed to have no slip-agents added, which would make it good for long term use...I haven't used it though....my experience comes with Mylar D and polypropylene mostly. As far as I know, there's only one supplier of a notebook page in HDPE, although there are some made I think in minilab formats, of 4 negs to a strip in a long roll length.

You can get envelopes from the archival vendors as well...usually you'd use a acid/lignin free, buffered envelope for b&w, unbuffered for color. There are some newer enclosures on the market that use molecular traps in the paper itself that act as a shield to environmental pollutants...these are sold under the Microchamber name...a similar product to the Artcare framing boards. This might be a good choice if you had alot of ozone, formaldehyde gassing off carpets, oil based paints, auto exhaust--urban areas, etc.

The cheapest way to do it, is to get a pH pen & check out a high-quality office envelope...it will have adhesives in the seams, which isn't the best, but you can find a good enough envelope this way...uh.....what else?? We use cabinets made for storing negs--they're baked enamel & steel and are made by Russ Bassett...they carry a cheaper line under the name Visuflex, another type is made by Corry. I think Safco might have a similar cabinet...basically it's a file cabinet made for negs, microfiche or microfilm...the ones we use accomodate roll film & sheet film....you can get smaller kits--using flip top boxes, from the archival vendors...a kit will often have everything needed for 25 rolls or so. You can spec out the sleeving material usually....make sure you wear some cotton gloves when you handle your film too...skin oils are the worst in the longterm for negs & prints...get in the habit early.

The best resource for this, is Henry Wilhelm's "Permanence & Care of Color Photographs" or the product catalogs of some of these suppliers, LI and Gaylord for instance, have good tech pamphlets. Here are some links though:

http://www.nedcc.org/plam3/tleaf411.htm

http://lcweb.loc.gov/preserv/supply/images/decphoto.jpg

Oh yeah, there is a standard used by the ANSI/ISO groups for photo storage materials...it's called the PAT. It tests for chemical changes in materials...look for paper & plastics that pass the PAT. Usually this is advertised in the specs if the product has been submitted...it's more often used for papers though, but the "safe" plastics are Mylar D, polypropylene and polyethylene..as long as they're uncoated...it all hinges on a good environment as well, so look at that too...don't put all your money in top-notch sleeves & envelopes if you can't control the environment to begin with...

Hope this helps, and: Opinions expressed in this message may not represent the policy of my agency.

-- dk thompson (kthompson@moh.dcr.state.nc.us), May 13, 2002.

In two words, avoid PVC. For more info, read the above response...

-- George Papantoniou (papanton@hol.gr), May 15, 2002.