 Photomicroscopy
and Macro Photography
 As
with aerial archaeology, I am
investigating simple, low-cost approaches to microscopy
and macro photography using light outside the visible
spectrum and blue light where it can be used as a
substitute for the near ultraviolet (NUV). In general, I
will be using relatively low intensity light sources. This
page is intended as a non-sequential blog on my journey,
with bits added/removed along the way. I will specify
filters etc when I believe that I have the most
cost-effective solutions. I will keep the text brief and
introduce the various topics with specific examples,
including details of the equipment used.
 John
with grandson Jack
Professionally,
I started using microscopes for biological work in 1972
for observing freshly explanted human tumour cells in
vitro and also their chromosomes. Before then, my
microscopy was limited to physics and measurement. Soon
afterwards, I worked on blood and with hair follicles in
vitro. Amongst other
things, I was interested in the effects of
ionising radiation on skin, hair growth and on
micronucleus production in relation to biological
radiation dosimetry following accidental non-uniform
exposures (eg Chernobyl).
I was
intrigued to discover that grey/white human hair can act
as an annular light guide (Nature, 338, 23, 2 March 1989, see here for a recent review). The
central core of the hair, the medulla, does not transmit light
but the medulla can disappear, following hair growth after
exposure of the hair follicle to ionising radiation in
vivo (Int. J. Rad. Biol, 58, 2, 383, 1990) and
probably after exposure to other cytotoxic agents too.
Sometime after irradiation and regrowth, the medulla can
reappear with the length of the medulla deletion (and any
reduction in hair diameter) being dose-dependent.
Transmitted
and Reflected Near Infrared Light
Microscopes
with LED illumination, like the one below, need a tungsten or halogen substage lamp for
transmission work in the near infrared (NIR). My tungsten
lamp with NIR pass filter on top (eg 720nm, 850nm etc),
when needed, will only just fit between the base and the
iris. To visualise an image you need an NIR camera. The
tube camera below has an NIR blocking, hot mirror filter
at the end of the tube which can be removed, thereby
converting it easily into a 'full spectrum' camera.
 Camera
set-up for normal visual spectrum work
When
using a standard camera body for NIR work on a microscope
and for macro photography it will need to have its hot mirror filter removed as
with the image below:
 A Gerbera flower viewed
through a 720nm infrared filter (Macro - click on image
to enlarge)
January
2020
 A copystand (~£60) can be used for both macro photography and experimental microscopy. The camera rail (~£20) at the lower left is also useful Transmitted
and Reflected Near Ultraviolet Light
I am looking at the lowest cost
solutions for using UV light which relies on
observation via a converted camera and, ideally, a monitor.
Ultraviolet is potentially
damaging to the eye, so I will go into much more detail
later. A UV light source should not be observed directly.
Ideally, a monocular microscope should be used (or digital
microscope) fitted with a camera to avoid the risk of
direct observation. I always have a pair of 190-540nm protective goggles to hand.
 A Gerbera flower illuminated obliquely with a TATTU V2 3W 395nm torch with a 52 mm threaded ZWB2 filter on the front (held in place with a thin ring of Blu Tack) to remove any residual visible light and a visible light blocking filter on the camera (Macro - click on image to enlarge) Autofluorescense
I will add more about autofluorescence (2) later.
 A Gerbera flower illuminated
with a TATTU V2 3W 395nm torch with a 52 mm threaded ZWB2
filter on the front (held in place with a thin ring of Blu
Tack) to remove any residual visible light (Macro
- click on image to enlarge)
January
2020
Fluorescence
using Dyes
I will add more about
fluorescence microscopy later. The technique usually
involves expensive equipment. Over
the decades, low cost approaches have been proposed with
more recent ones including
a portable blue LED illumination set-up
and a simple UV microscope built using off-the-shelf components.
Flourescence
Backlight Staining
The fluorescence backlight
staining technique (FBST) involves converting a
solid piece of tissue into a light source. The tissue is
stained with a fluorescent dye and illuminated with
ultraviolet or blue light. Superficial cells on the
surface can be conventionally stained for observation.
This technique can be used on large hand-cut sections as
well as whole specimens.
In the example here, I used a
Nikon fluorescence microscope. I intend to demonstrate
this technique with a conventional microscope.
Fluorescence
backlit superficially stained solid tissue
(A
plucked hair follicle acting like a light bulb)
1988
Grandson Jack with his two little microscopes |
gmail.com