Spectrophotometers require several minutes to perform the same task. Accordingly the diode array instruments can be used to monitor processes that occur on very fast time scales. Conventional spectrophotometers require several minutes to perform the same task. Typically the halogen is iodine. As WI encounters the hot filament, the molecule decomposes and tungsten is redeposited on the filament.
Light scattered or lost from the sample has the net effect of making the absorbance appear greater.