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OPTICAL STAINING PART ONE When we learn about microscopy most of
the time brightfield is the illumination
Alejandro Ariel Garcia Arriaga, Coacalco method that we are introduced to at first
Estado de Mexico, Mexico. and we are told that for achieving contrast in
an optical microscope we need stains for the
INTRODUCTION: transparent samples of the microscopic
world. This is partially true because the
Observing things that are beyond our sight is majority of samples for example in Pathology
amazing, even more so when things on a or Histology are made with stains and
microscopic scale are most of the time observed in bright field. Even more so, the
transparent. But sometimes this property of properties of the samples are expressed
the microscopic world becomes an obstacle according to their reaction to the stains. For
mainly for the enthusiast microscopist. example, as in the case of bacteria they are
Nevertheless, there are many ways we can classified as gram negative or gram positive.
overcome this inconvenience; within this and
a subsequent article I would like to show you Nevertheless for the enthusiast microscopist
how we can make microscopic things visible it is difficult sometimes to obtain these kind
with beautiful techniques that I have learned of stains. If somebody has a microscope,
in my searches for enhancement methods. most of the time it is supplied with a
brightfield condenser and has no stains
DEVELOPMENT: supplied at all. Does that mean that we
cannot observe some samples? Of course not
When we learn the theory about microscopy because it is possible to do optical staining.
we learn something very important i.e. in
order to see a microscopic object it must Optical staining? Yes, optical staining is a
have enough contrast and resolution. These concept that I learned from my searches
two concepts are very important to looking for forms of enhancing my
understand since they are the basis of all observations and the first technique I found
observations. was Rheinberg filter illumination but now I
have seen that there are many other
So I am going to define contrast, as the beautiful methods.
difference in illumination between an object
and the background, I have learned that it is Optical staining then is the capacity of
possible to alter contrast by changing the providing contrast to a transparent
background illumination, or by changing the microscopic sample without using real stains
object illumination. but instead using filters or stops placed on
the light source or in the filter tray of the
Resolution can be defined as the capacity of condenser.
the microscope for making possible the
differentiation between two objects. In the In the present article OPTICAL STAINING is
case of optical microscopy ca. 0.25 also a variation that you can carry out with
micrometer is the possibility since it is the software of a microscope camera.
limited by the light wavelength.
