Large sections of leaves can be easily prepared in 6 mm carriers with the HPM100 if the internal air spaces are filled with hexadecane. The two-step substitution process with tannic acid followed by osmium helps preserve and contrast membranes. The ER, Golgi and tonoplast membranes are particularly visible in this preparation. The chloroplasts were very well preserved with minimal extraction as reflected in the dense stroma especially surrounding the starch grains. This causes the thylakoids to appear in reverse contrast to chemically fixed samples.