If you were wondering why Microscopy isn’t more popular here’s a little article I
put together on why this may be the case. Download (.pdf format)
I’ve exported all the garden exploration pages as high resolution (2400 x 3500 typically)
jpeg images and zipped them into one file. They print out nicely at A4 and possibly
A3 at a push, they could be used to brighten up a corner of the classroom. Download
(.zip 10MB approx)
If you are interested in looking at and identifying algae, here are a couple of downloads
to get you started.
A Beginner’s guide to freshwater alga, published by Her Majesty’s Stationary Office
(HMSO), is a small guide with descriptions and line drawings of 110 of the algae
genera most likely to be found. A scan of the book in .pdf format can be downloaded,
for non-profit use, from the Natural Environment Research Council (NERC). Download
The following download consists of 6 colour plates illustrating some of the more
common forms of algae. I found the files tucked away on a University website as part
of a public domain literature digitisation project. The plates show algae grouped
in terms of likely habitats e.g. Surface water, filter clogging, resevoir etc. The
images look like the originals were watercolours and make lovely wall posters in
their own right. Download (.zip format)
As you may have gathered from the garden tour, Lichens are an interesting subject
in their own right. I found the British Lichens site very useful, especially the
option to show the entire collection of thumbnail images. If you do this, you can
save the rather large HTML page and use it offline as an interactive identification
In Firefox and with the page open, use the ‘Save page as’ option under the file menu.
You should be able to save a file called ‘pictureindexcomplete.html’ together with
a folder ‘pictureindexcomplete_files’ which has all the .jpg thumbnail files in.
Click on the saved pictureindexcomplete.html file and it should open as if you are
online. Just mouse over the images and the Lichen name is in the image link title,
which appears at the bottom of the screen. www.britishlichens.co.uk
Image Processing using Picolay
As anyone who has done close-up/macro photography knows, the more you try and magnify
an object, the narrower the depth of field (smaller range of distances over which
the object is in focus). Under a microscope this effect becomes extremely apparent
which is part of the reason why prepared slides tend to be very thin sections. However,
there are times when it is not easy or practical to prepare thin sections, instead
the microscope’s fine focus can be used to ‘scan’ through a specimen. This is OK
if you are sat at the microscope but not so good if you want to record the image
using a camera.
One solution to the problem is to use focus-stacking software which basically allows
you to take multiple images in different focal planes and combine them into one image,
using only the parts of each image that are in focus. This is actually quite complicated
image processing, but a very nice gentleman called Heribert Cypionka has written
some software called Picolay that makes it remarkably easy to do. The 3 images below-left
are the raw images, the 4th image is the post-processed result using Picolay.
Images of Hollyhock pollen processed with Picolay.