80 PART IV Digital Documentation
Development of New Optical Glasses
Unfortunately the quality of optical glass produced during that period was not
sufficiently high to provide the theoretical resolution that was dictated by Abbe’s
»resolution formula«. There was definitely the need for high-quality glass. Then
Abbe met Otto Schott, a glass chemist, in 1881. Together they developed several
new glass formulas and made adjustments to the mixing and annealing process
to
eliminate
internal defects and produce optical-grade glass with a uniform refractive
index. Finally, in 1886, they introduced a new type of objective, the apochromat.
The creation of apochromat objectives eliminated color aberrations, which greatly
assists bacteriologists in identifying infectious bacteria, and brought the resolv-
ing power of the microscope to the limit we know today.
