[Taxacom] Digital herbarium

[Sean Edwards]

Just a couple of points, mostly from a few years back when we considered this:

1. Problem with scanners is that it means either turning specimens upsidedown (bad thing), or buying an expensive upsidedown scanner. We made a transparent folder for turning specimens upside down, but handling and electrostatic problems caused more damage.

2. Problem with DSLR cameras is the usual:
a. they need a copy stand to keep them square (no too much of a problem);
b. even the best macro lenses will have optical faults (most now are very good, and things like lateral chromatic aberration can be routinely sorted afterwards);
c. dust on sensor (standard DSLR problem even with self-cleaning sensors, just something you have to deal with);
d. white balance, even lighting, etc. (no real problem, just be aware of it in your set-up -- four flash guns evenly cornered at good distance and 45 deg, but just two at the ends works perfectly well).

Maybe scanners have moved on recently?

Sean

~~~~~~~~~~~~~~~~~~~~~~~~~

Sean Edwards, email: sean.r.edwards at btinternet.com


  ----- Original Message ----- 
  From: Gurcharan Singh 
  To: taxacom at mailman.nhm.ku.edu 
  Sent: Saturday, February 20, 2010 6:35 AM
  Subject: [Taxacom] Digital herbarium


  Dear members

  For some time I was thinking of initiating a thread on digitising herbarium specimens, but was reluctant because whenever there is mention of digital herbarium, there is always mention of a scanner. I have worked with scanners (though not high end ones), but always find a good digital SLR camera giving very good results. I had started this with old photographs in our family albums, and when I thought of digitising my personal and College herbarium specimens, I found Digital SLR camera much more handy and useful. Today I got this encouragement from MBLWHOI Library Digital Herbarium.

  "Specimens too bulky or fragile to be scanned will be photographed with a digital camera" 

  Personally I feel Digital SLR camera is much more useful, as it saves a lot of time as compared to a scanner. My question is if Digital SLR camera can give good results with fragile and bulky specimens, and is much more faster than a scanner, why not to use it in routine procedures.
     May someone with good experience with both can give better opinion.


  Dr. Gurcharan Singh
  Associate Professor
  SGTB Khalsa College
  University of Delhi, Delhi
  India
  http://people.du.ac.in/~singhg45