The supplier of much of my daguerreotyping paraphernalia, Talas, published a great blog post recently about Buffered Tissue vs. Unbuffered Tissue. I have tried various products to seal my daguerreotypes and I’ve used both buffered and unbuffered tapes from Talas with varying results. I’ve even written about the necessity of sealing daguerreotypes but what I haven’t talked with you about is how the tape itself and be a source of corrosion. I can’t speak to the long-term effects of the tapes but here are my thoughts on three popular rolls of sticky stuff:
Permacel (recently renamed Nitto Denko) J-Lar ($13.50, 1x72yds): Alarmingly clear Superman tape. The stuff is strong, really sticky, and forms an excellent vapor barrier. J-Lar is also good enough for the Library of Congress for resealing daguerreotypes.
Neschen Filmoplast P-90 ($19.10, .75x54yds): A gossamer pressure-adhesive tissue tape suggested to me by other daguerreotypists for years. The stuff is buffered with calcium carbonate to a pH of 8.7 which makes me a little nervous. I’d love to hear from some chemist-types about what this buffering agent will do to silver over the years. (Note: There now exists P-90 PLUS which doesn’t appear to be buffered.)
Lineco Foil Back Frame Sealing Tape ($11.99): This is what I use. It’s superman tape and it’s buffered but the buffering is of the paper and not the aluminum that contacts the daguerreotype plate. The aluminum “provides a barrier that stops acid migration and meets the FACTS standard”. If you haven’t ever heard of the Fine Art Care and Treatment Standards (FACTS) then you’re not alone. Check it. The stuff tears easily (J-Lar doesn’t) and is relatively inexpensive.
As I’ve said before, we can scarcely do worse than our Daguerreian forefathers in sealing our preciouses. It’s likely that any of the above tapes and any of a dozen others will keep our frozen mirrors safe from chemical nasties for hundreds of years.
Thanks for the informative post! I am still struggling with the best sealing method, especially since I am currently working with daguerreotype “miniatures”. It taxes my (lack of) hand-eye coordination.
Do you just run a single strip of tape around the edge of your package and then fold it over on the front and back? Or is your method more elaborate? I have also wondered about aluminum in contact with silver. The galvanic differential between the two is high enough to potentially cause corrosion.
p.s. When is your San Jose art project happening? I will go look at it for you.
I run a single strip attached to the edge and fold it underneath the package.
I hadn’t considered the effects of the two metals being in contact. Do you have any research that suggests these two would be problematic?
I’d venture to guess that it would be far more likely that a contaminant inside the plate would corrode it far before the tape would corrode.
While I am not a chemist, I learned of a trick years back on cleaning tarnished silver without abrasives or even much work. It uses the galvanic principal of two dissimilar metals plus an electolyte….
You take an small aluminum saucepot, half fill it with water, add a teaspoon or two of table salt, stir to disolve, and finally add the tarnished silver item. The process is accelerated if the water is warmed up gently. The tarnish vanishes after a few minutes and the piece comes out shiny clean.
Lacking aluminum cooking pots, I have placed a piece of aluminum foil in the bottom of a glass pyrex bowl and added a hot salt-water solution with equally favorable results – at least in terms of jewelry cleaning.
I have to wonder if given sufficient time, a small amount of moisture, and errant fingerprints to provide the salt, if something “unfavorable” could occur with a precious Dag sealed with bare aluminum tape?
Something to think about…