Time interval during which vertical blanking is applied. E. g. , in 625 line systems the Vertical Blanking width is 25 lines plus Horizontal Blanking Interval.

a blank sample that is placed in a sample bottle at the field site, and is handled the same as a normal sample

an unexposed control filter meant to account for background interferences and systematic contamination in the field, spurious effects due to manufacturing and storage of the filter, and systematic analytical errors