Timm Piper´s microscopy site

Copyright: Jugend forscht

Timm Piper´s
microcopy site
Principles of VBDC
Principles of VPDC
Principles of VPBC
Materials and Methods
Results of VBDC
Results of VPDC
Results of VPBC
Further developments
Further developments
Further devepolments
Optical calculations
Summarizing remarks
and conclusions
Video Downloads
List of Personal 
About me
Contact Details

Dear readers,

On the following pages, I present my work dealing with several new illumination techniques in light microscopy which lead to fundamental improvements of the image quality and enhanced visual information, especially in examniations of so-called “problem specimens”. In particular, the three-dimensional architecture of complex structured specimens can be visualized in superior clarity as can superficial textures and fine details inside transparent specimens. High density light absorbing or light reflecting structures and low density phase shifting structures can be simultaneously imaged. In specimens characterized by high ranges in regional thickness and density, all zones can be simultaneously observed in maximum image quality. The complementary information of microscopic images based on bright-field, dark-field and phase contrast is combined in the resulting images and typical artifacts such as haloing, shade-off, blooming and scattering are reduced. Thus, the images achievable with my new methods are characterized by loss of artifacts, improved precision in visualizing of fine details, enhanced focal depth (depth of field) and excellent lateral resolution. In many scientific fields dealing with light microscopy and using bright-field, dark-field and phase contrast as standard techniques, the new methods presented promise fundamental improvements – in live observations as well as in photomicrography.

In December of the year 2010, it all began with a snow flake I prepared as a varnish cast by use of the embedding medium “Entellan”. This was a difficult and time-consuming task, but finally, I succeeded in preparing a single flake situated plane and symmetrical at the surface of the agglutinant film (Entellan layer). Nevertheless, I was disappointed by the flat appearance of the microscopic images I could obtain from my preparation when using normal illumination techniques. In brightfield as well as in darkfield illumination, only the marginal contours could be clearly perceived whereas the three dimensional morphology, especially the vertical impressions of the varnish cast could not be visualized. And so, at the beginning of the new year, I tried to modify the pathway of the illuminating light in order to accentuate the snow flake´s relief and three-dimensional morphology. As a result of these experiments, variable bright-darkfield contrast (VBDC) was implemented. After this task, the new method was evaluated with several other specimens observed at different magnifications. Next, standard darkfield was replaced by axial (central) darkfield based on appropriately designed light stoppers. Further, brightfield was replaced by phase contrast so that variable phase-darkfield contrast (VPDC) could be carried out. Finally, phase contrast was combined with brightfield so that variable phase-brightfield contrast (VPBC) could be implemented. By use of this method, light absorbing details could be observed in maximum quality together with low density phase shifting structures. In VPBC, bicolor light filtering and separation of both illuminating light components associated with phase contrast and brightfield turned out to be the “key to success” so that phase contrast images could be superimposed with brightfield images without being “disturbed”.

According to my practical evaluations carried out, the methods presented could be of special interest for diatomists, biologists, geologists and paleontologists who are interested in examinations of diatom frustules or shells of foraminiferida and radiolarians. Moreover, I expect also a fundamental gain in examinations of nannofossils which are of a size near the resolution limit given for light microscopes. Also in crystallographic examinations, my methods can contribute to improved quality of microscopic imagery. In biology and medicine, my methods can lead to enhanced visual information when composite specimens have to be examined consisting of low density phase shifting and high density light absorbing or reflecting details. Thus, for instance, high density inclusion bodies and deposited material inside of cells or situated at the interstitial space can be visualized in enhanced clarity together with surrounding low density cellular components. Also in specimens consisting of thin and thick zones, the global information will be maximized. In such specimens mentioned, all details can be detected in maximum precision. As the lateral and vertical resolution (focal depth, depth of field) are both maximized, my methods can also lead to improved image quality and visual information when bacterial cells have to be examined at maximum magnification. When the techniques elaborated for transmitted light are implemented in vertical illuminators for use in examinations in incident light, also industrial engineers could use my techniques for improved quality in material controlling and material sciences.

The methods presented might have a great potential to be commercialized by manufacturers who are engaged in producing microscopes. The techniques developed could be implemented in standard equipment for low or moderate cost so that normal laboratory microscopes could be fitted with these attractive features. Thus, microscopists could upgrade their microscopes already used and use my methods in addition to the common standard techniques without investing in a new microscope.

At the German contest for young researchers “Jugend forscht”, my inventions were awarded first prize for physics in May 2012, and they were nominated for the 24th European Union Contest for young Scientists (EUCYS) which took place in Bratislava on September 21-26,  2012. At this contest, my methods were awarded the Eiroforum special donated prize.

My original paper (written in German) which was commended at the "Jugend forscht" contest can be downloaded from the homepage of the German Society for Non-Destructive Testing (DGZfP):


For the German version of my Homepage please visit www.timm-piper.de


Last Update: August 10th, 2012
Copyright: Timm Piper, 2012