Optical channel count changes captures without changing per-field dwell time. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
One channel gives one capture per field
Hold fields at 3 and dwell time at 4 s. One channel gives 3 captures while total time stays 12 s.
3⋅1=3
Two channels give six captures
Channels 2 give 6 captures over the same 3 fields and the same total time 12 s.
3⋅2=6
Three channels give nine captures
Channels 3 give 9 captures. This scan counts deterministic exposure settings, not spectral cross-talk or unmixing.