[Taxacom] BHL survey: scan quality

Pat LaFollette pat at lafollette.com
Fri May 7 23:25:45 CDT 2010

I agree that the quality of plates in the BHL (=IA) PDF files are 
often inadequate due to  excessive compression.  I addressed this in 
the comments section of the BHL questionnaire.  The specific survey 
question did not allow a distinction between text (which is usually 
okay) and plates (which are often not).

The original images, available in the *_jp2.zip files, are much 
better than in the PDFs.  I suggest that anyone unhappy with the PDF 
image quality take a look at the jp2 images.  I use these exclusively 
and no longer bother with the PDF files at all.

The BHL (meaning IA) imaging workflow is essentially the same for 
every book processed.  Customizing the process for each work would be 
prohibitively labor intensive. The paper in many 19th and early 20th 
century books is too discolored to be scanned directly to 
binary.  The result would be illegible.  The alternative is to 
photograph everything in color.  Given a choice between imaging 
relatively few books really well, or many more books adequately well, 
the latter, in my opinion, is by far the better course.  Image 
absolutely as many works as possible while funding to do it is available.

If a binary rendering of the text is needed, very good results can be 
achieved by subtracting the paper color from the image and enhancing 
contrast before reducing the image to binary. The results can be much 
superior to scanning the pages directly to binary.  If anyone would 
like a description of the process, using PhotoShop, contact me off list.


At 10:27 AM 5/7/2010, Francisco Welter-Schultes wrote:
>Dear Taxacomers,
>thank you all so much for having participated in the BHL Survey 2010.
>We obtained more than 1000 answers, of which more than 60 % were by
>taxonomists. This gives us really good preconditions to continue our
>The next step for us consists in evaluating the results. We will talk
>about these in our BHL/BHL-Europe conference in Vienna (Austria) at
>the end of this month and then we are certainly going to present the
>results for all of you in an internet page that we will set up so
>that you can see what the participants answered.
>I have one question. There is one result in the survey that I do not
>understand. When we were asking "how satisfied are you with the
>following functions of BHL" the levels of agreement with all
>functions were surprisingly high. The differences were only
>finely tuned. It is noce to get such a positive feedback, but on
>the other hand this makes it more difficult to improve our
>service. One of the highest levels of agreement (73 %) was recorded
>for the scan or image quality. Being a taxonomist myself I know that
>the scan quality (for example when I look up plate figures) provided
>by Smithsonian, Natural History Museum London, Harvard and Missouri
>Botanical Garden are relatively low. Does the high level of agreement
>with the scan quality mean that plate figures are not needed for your
>work, only the texts? Or does it mean that you are happy that
>anything is provided at open access at all, so that you did not dare
>to complain about the quality? Or was a misunderstanding provoked by
>the wording of the bullet point ("The scan or image quality is fine"
>- Strongly agree, Agree, Neither agree or disagree, Disagree,
>Strongly disagree)?
>I anticipate that there will be discussions about this point in the
>meeting in Vienna. Since I have no idea for an answer, we would be
>left in speculations, so I have decided to ask you.
>Thank you for your precious help.
>University of Goettingen, Germany
>Taxacom Mailing List
>Taxacom at mailman.nhm.ku.edu
>The Taxacom archive going back to 1992 may be searched with either 
>of these methods:
>(1) http://taxacom.markmail.org
>Or (2) a Google search specified 
>as:  site:mailman.nhm.ku.edu/pipermail/taxacom  your search terms here

Patrick I LaFollette
Research Associate in Malacology
Natural History Museum of Los Angeles County
pat at lafollette.com 

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