. ▁Number ed ▁symbols ▁( called ▁' visual ▁indic ators ') ▁on ▁the ▁cart ridge ▁end ▁indicate ▁the ▁status : ▁▁ ▁Full ▁circle : ▁Une x posed ▁ ▁Half ▁circle : ▁Part ly ▁exposed ▁ ▁Cross ▁sign : ▁Ful ly ▁exposed ▁but ▁not ▁processed ▁ ▁Rect angle : ▁Process ed ▁ ▁Additionally , ▁a ▁tab ▁on ▁this ▁end ▁of ▁the ▁cart ridge ▁indicates ▁that ▁the ▁cart ridge ▁has ▁been ▁processed . ▁ ▁Information ▁exchange ▁▁ ▁A ▁major ▁distinction ▁of ▁A PS ▁film ▁was ▁the ▁ability ▁to ▁record ▁information ▁other ▁than ▁the ▁image . ▁This ▁information ▁exchange ▁was ▁most ▁commonly ▁used ▁for ▁print ▁aspect ▁ratio , ▁but ▁could ▁also ▁be ▁used ▁to ▁record ▁the ▁date ▁and ▁time ▁that ▁the ▁photograph ▁was ▁taken , ▁store ▁a ▁ca ption , ▁and ▁record ▁expos ure ▁data ▁such ▁as ▁sh utter ▁speed ▁and ▁a pert ure ▁setting . ▁This ▁information ▁could ▁be ▁read ▁by ▁the ▁photo ▁printing ▁equipment ▁to ▁determine ▁the ▁print ▁aspect ▁ratio , ▁print ▁information ▁on ▁the ▁back ▁( or , ▁rarely , ▁the ▁front ) ▁of ▁the ▁photograph , ▁or ▁to ▁improve ▁print ▁quality . ▁ ▁Two ▁methods ▁for ▁storing ▁information ▁on ▁the ▁film ▁were ▁employed : ▁" mag net ic ▁IX " ▁and ▁" opt ical ▁IX ". ▁Opt ical ▁IX ▁was ▁employed ▁on ▁less ▁expensive ▁cam eras ▁and ▁dispos able ▁cam eras , ▁and ▁employed ▁a ▁light ▁source ▁to ▁expose ▁a ▁small ▁section ▁of ▁the ▁film , ▁outside ▁of ▁the ▁image ▁negative ▁area . ▁This ▁method ▁was ▁limited ▁to ▁determ ining ▁the ▁print