. ▁ 0 x 8 0 ▁in ▁hex ade c imal ). ▁The ▁file ▁expects ▁to ▁make ▁use ▁of ▁the ▁E H B ▁( Extra ▁Half - B rite ) ▁mode ▁of ▁the ▁Am iga ▁ch ips et . ▁The ▁colour ▁map ▁will ▁have ▁no ▁more ▁than ▁ 3 2 ▁entries , ▁but ▁the ▁image ▁will ▁have ▁ 6 ▁bit plan es . ▁The ▁most ▁significant ▁bit plane ▁should ▁be ▁regarded ▁as ▁a ▁flag , ▁when ▁un set , ▁use ▁the ▁lower ▁ 5 ▁bits ▁as ▁an ▁index ▁into ▁the ▁colour ▁map ▁as ▁usual . ▁When ▁the ▁flag ▁is ▁set ; ▁use ▁the ▁lower ▁ 5 ▁bits ▁as ▁an ▁index ▁into ▁the ▁colour ▁map , ▁but ▁the ▁actual ▁colour ▁to ▁be ▁used ▁should ▁be ▁half ▁as ▁bright , ▁which ▁can ▁be ▁achieved ▁by ▁shift ed ▁the ▁R GB ▁components ▁of ▁the ▁colour ▁one ▁bit ▁to ▁the ▁right . ▁Alternatively , ▁create ▁a ▁colour ▁map ▁with ▁ 6 4 ▁entries , ▁and ▁copy ▁the ▁lower ▁ 3 2 ▁entries ▁into ▁the ▁upper ▁half , ▁converting ▁them ▁to ▁half ▁bright ness ; ▁then ▁use ▁all ▁ 6 ▁bit plan es ▁as ▁a ▁colour ▁index . ▁ ▁P B M ▁images ▁cannot ▁exist ▁in ▁extra ▁half - br ite ▁mode . ▁ ▁Hold ▁and ▁Mod ify ▁ ▁If ▁the ▁IL B M ▁file ▁contains ▁a ▁C AM G ▁chunk ▁in ▁which ▁bit ▁ 1 1 ▁is ▁set ▁( i . e . ▁ 0 x 8 0 0 ▁in ▁hex ade c imal ) ▁the ▁file