Final answer:
A karyotype chart is best produced by photographing chromosomes during the metaphase stage of mitosis, when the chromosomes are aligned at the equator of the cell, making them easily distinguishable for analysis.
Step-by-step explanation:
During mitosis, there are five stages in which the cell's chromosomes become visible and are separated into identical sets to prepare for division into daughter cells. Producing a karyotype chart involves photographing the chromosomes during the metaphase stage. In metaphase, chromosomes are aligned at the cell's equator, making them highly organized and easily distinguishable. At this point, when cells in metaphase are subjected to pressure, they burst, which allows the chromosomes to spread out. This spread facilitates the creation of a karyotype chart by staining and visualizing the unique morphological variations among the individual chromosomes, such as length, banding pattern, and centromere position.