How to convert slides of herbarium specimens into good quality web site images?

Dr. Gerald Stinger Guala stinger at FAIRCHILDGARDEN.ORG
Fri Dec 15 15:25:39 CST 2000


We have a few thousand images from slides on the web and the quality varies
widely from "we had no clue" to "I think we got it" over a 2 yr span.  The
first thing is that you need to scan at high res with a good scanner to a
bitmapped file such as a TIFF or BMP - this will be a very large file. Then
you optimize (with photoshop preferably - see Una Smith's comments) and then
you have a choice to make. You can either make a big Jpeg that takes a while
to download or you can use a good quality compression package. Luratech
makes a good one but you need a plugin to view the images, Flashpix is good
but the serving software is really expensive and flaky I've found.  The best
that we have seen is Mr.Sid from Lizardtech. You can compress images up to
2000 pixels on a side to 1/10th their size with no reall loss in image
quality and serve them over any NT based system with the shareware version
that is like $49 to purchase. Warning you have to install Perl under the
server software and this can be tricky but easy for a techie. The $1200
Intel compatible workgroup software or the $249 MAC photoshop plugin have
input image size limits of 500 Mb so you can get a 24 bit 8,000 X 10,000
pixel image encoded and served with them and serve it reasonably to the web.
It isn't easy but it works. We're testing it for our Types right now.


-----Original Message-----
From: Taxacom Discussion List [mailto:TAXACOM at USOBI.ORG]On Behalf Of
Diana Horton
Sent: Friday, December 15, 2000 1:44 PM
Subject: How to convert slides of herbarium specimens into good quality
web site images?

I have some excellent quality slides of herbarium specimens, and I would
like to put these up on a web site.  We tried scanning the slides using a
Polaroid Sprint Scan (for slides), and the results were disappointing - the
images were very fuzzy when blown up.  That presumably reflected the fact
that they were scanned at 500 dpi; however, if we used higher resolution to
scan, the images would take *forever* to come up on a web site, so that
wouldn't be practical.  We then tried taking photos of the slides with a
digital camera.  Those images are much sharper than the scans of the
slides, but they're still nothing comparable to the original slides.  The
last thing we've tried is to have prints (of the slides) made and then to
scan the prints.  However, the latter costs $10/print (for good quality
prints), and that becomes pretty pricey on 20+ slides!

Can anyone tell me how to go from a slide image to a web image of
comparable quality (i.e., sharp and clear, even if the viewer increases the
magnification) that can be downloaded in a reasonable time frame?!

Thank you!

Diana Horton
Curator, University of Iowa Herbarium
Associate Professor, Department of Biological Sciences
312 CB
University of Iowa
Iowa City, IA  52242-1297

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