Darkfield illumination is a concept that was used by darkfield microscopes. Darkfield microscopes, on the other hand, are special types of microscopes that produce an image of the specimen against a dark background. If you are at a loss whether you should use these devices or not, you can use the article below as a guide.
When you are to apply the principles of darkfield illumination, what you are really doing is viewing a certain sample against a dark background. And primarily because of that dark background that was produced, the sample under view appears brightly than the usual.
The main advantage of using darkfield illumination is that you can actually see the intricate details of the samples you are looking at. In a normal microscope using the principles of bright field microscopy, these details are not normally resolved. You cannot possibly see these fine points of the specimen because the microscopes reflects the light instead.
To understand darkfield illumination better, visualize that you are inside a very dark room. When a certain beam of light passes through an opening, the dusts or the minute particles that were free flowing in the air and inside the room can be seen quite easily. If you open the lights though, these particles becomes invisible. When you really think about it, darkfield illumination has the ability to provide for an image with full accuracy and elements coming straight from a science fiction book.
When phase contrast illumination is compared with darkfield illumination, the resolution doesn’t suffer as much either. In fact, when the samples of these two microscopes are compared side by side, darkfield illumination produces the images that are way better than phase contrast illumination, using the same magnification powers of objective lenses and eye pieces. When it comes to contrast though, the one produced by darkfield illumination is better than the circular oblique lighting principle.
Much the advantage of using darkfield illumination is that its concepts have been around for ages. Darkfield illumination was used for more than several decades already. And this only signifies that all the techniques involved with it has been improved and enhanced over time. The principles surrounding its illumination system is in the process of being perfected and learned. Right now, darkfield illumination is the well understood. It is also the most approved lighting technique ever developed.
Another advantage of using darkfield illumination is that it is rather inexpensive. You actually need not buy a separate device to employ the concepts of darkfield illumination into your sample. All you have to do is to take your regular microscope or bright field microscope. And then get an suitably sized opaque condenser disc into the path of light that is located very close to the diaphragm condensers.
And ever a certain microscope is used with an objective that has a appropriate numerical aperture, the darkfield illumination it has can also be transformed into a circular oblique lighting system. If you like to adjust the darkfield illumination contribution, you can do so by manipulating the aperture of the condenser installed.
Phase contrast illumination system is the next best competitor of darkfield illumination. But then again, phase contrast illumination is not recommended for use with amateur microscope users. In essence, only professionals can use phase contrast illumination. And the microscopes that applies them can be really expensive too. A phase contrast microscope is priced from $800 to as much as two thousand dollars a piece.
It is also possible to use colored filters with the darkfield illumination system. And under the higher magnification systems of a microscope using the darkfield illumination technique, much better details of the specimen can be viewed.
If you are also concerned with the structure, dimensions, and boundaries of a certain sample, darkfield illumination is your best option too. Against a dark background, you can certainly see the expansions and edges of the sample. Same goes if you would like to view the movements of certain bacteria and other live microscopic samples.
Right now, there are different technologies being applied and added to the ever evolving darkfield illumination system. There are variable contrast control system that can be integrated to it as well so that the images produced becomes more enhanced and has better contrast. With the variable contrast control, it is possible to make the sample’s background lighter or dimmer. And when it is adjusted, the sharpness and brightness of the sample changes accordingly as well. So with all of these said, you should be able to answer confidently why you should use the darkfield illumination system.