[Nhcoll-l] Fwd: Labelling of alcohol-preserved specimens

[Doug Yanega]

On 4/3/13 7:31 AM, Daniel K. Young wrote:
> I was intrigued by Mark O'Brien's comment (Hi Mark)!  I have learned 
> (and taught) just the opposite: do NOT use inkjet & bubblejet printers 
> because the letters readily dissolve in EtOH (and I've witnessed 
> that). In the case of simply xeroxed labels, the letters readily life 
> off the paper. As for laser printers, it has been my experience (and, 
> alas, I'm old enough to have had a lot of experience) that as long as 
> the heat is sufficient, the plasticized carbon will generally NOT lift 
> off the paper.  I am looking at EtOH laser-printed labels that were 
> printed more than 25 years ago and have been in 80% EtOH since - they 
> look "good as new."
Whenever this topic comes up, I hasten to remind people that (1) the 
same printer using different paper can give wildly different results, 
and (2) there are virtually no hard "longevity" data (as in controlled 
experiments) for different combinations of printers and paper. As such, 
as a community we are confronted mostly with anecdotal data, which may 
(as in the case above) appear to be in conflict, when in fact both sides 
may be correct. I have laser-writer labels produced at KU in 1990 that 
are sitting in ethanol and are all perfectly fine today, while labels 
from that exact same printer but produced one month later on a different 
batch of paper had the letters float off the instant they touched the 
ethanol. My point is that unless a person making a recommendation can 
tell you the EXACT printer they used, and the EXACT paper they used, AND 
how those labels have held up over a span of years, then you can't 
assume that their recommendation is trustworthy.

Another example, which folks like Andy should find interesting: we have 
a Saito thermal printer, identical to the one used by the insect folks 
at the AMNH (we got ours based on their recommendation). Out of 
curiosity, when we first started making labels with it, I took a few 
chunks of test labels and soaked them in water overnight. The next 
morning, the surface of the labels had become somewhat gelatinous with 
fine visible wrinkling (as if it had absorbed water), and a moderate bit 
of friction rubbed all the printing clean off. Why was I able to achieve 
such a disastrous effect so easily, when everyone else seems to swear 
that thermal-printed labels are great for wet collections? Well, (1) not 
everyone uses a Saito printer (2) maybe water is somehow worse than 
ethanol, though since all ethanol solutions contain water, over time I 
can't imagine why the same effect shouldn't occur, regardless of the 
concentration (3) we had ALSO followed the recommendation of the people 
at the AMNH (who swore by the technique) of asking the manufacturer that 
the thermal plastic be re-spooled prior to shipping so what was normally 
the bottom side of the plastic was on the *top*. If I had to guess as to 
why I found that thermal labels are vulnerable to water when no one else 
has ever reported any such thing, I'm tempted to think that point #3 is 
the source of the discrepancy (i.e., that thermal plastic is not 
symmetrical). However, even if this were the problem, then the BACK 
sides of everyone else's thermal labels might be turning gelatinous, and 
who knows whether that coating may be rubbing or peeling off and 
contaminating their specimens? In our case, we presently use two 
inkjet-printed labels for our wet collections, one inside the vial, and 
another (identical) taped outside the vial, because we don't trust ANY 
labels' archival properties in fluid, and printing duplicate labels is 
cheap insurance for little extra labor.

Again, my point is that we are operating strictly via anecdotes, and 
don't have experimental results we can consult for objective assessments 
of one technique versus another. If it were possible to compile all of 
the observations from people who know ALL of the variable parameters for 
their cases, we might have a useful point of reference; obviously, if 
anyone knows of such a compilation, a lot of us would be interested.

Sincerely,

-- 
Doug Yanega      Dept. of Entomology       Entomology Research Museum
Univ. of California, Riverside, CA 92521-0314     skype: dyanega
phone: (951) 827-4315 (disclaimer: opinions are mine, not UCR's)
              http://cache.ucr.edu/~heraty/yanega.html
   "There are some enterprises in which a careful disorderliness
         is the true method" - Herman Melville, Moby Dick, Chap. 82

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