▁on ▁the ▁painting ' s ▁lower ▁left ▁frame ▁as ▁if ▁the ▁subject ▁had ▁just ▁suddenly ▁and ▁inform ally ▁arrived ▁to ▁the ▁sitting ▁and ▁cas ually ▁position ed ▁herself . ▁This ▁conce it ▁was ▁later ▁and ▁most ▁fam ously ▁em ulated ▁by ▁Pet rus ▁Christ us ' s ▁Port rait ▁of ▁a ▁Car th us ian ''' s ▁which ▁placed ▁a ▁fly ▁per ched ▁on ▁the ▁f aux ▁center ▁lower ▁border ▁of ▁his ▁canvas . ▁Van ▁E y ck ▁had ▁already ▁gone ▁further ▁than ▁this ▁however , ▁and ▁has ▁in ▁this ▁portrait ▁created ▁a ▁number ▁of ▁ill usion istic ▁pers pect ives . ▁ ▁From ▁surv iving ▁copies ▁it ▁can ▁be ▁dedu ced ▁that ▁apart ▁from ▁the ▁actual ▁o ak ▁frame ▁there ▁were ▁two ▁other ▁' p aint ed ▁on ' ▁frames , ▁one ▁of ▁which ▁was ▁letter ed ▁with ▁g oth ic ▁ins cription ▁to ▁the ▁top , ▁while ▁a ▁f aux ▁stone ▁par ap et ▁provided ▁support ▁for ▁her ▁hands ▁to ▁rest ▁upon . ▁ ▁Van ▁E y ck ▁painted ▁a ▁second ▁portrait ▁during ▁his ▁visit ▁to ▁Portugal , ▁his ▁ 1 4 2 8 ▁Port rait ▁of ▁a ▁Man ▁with ▁a ▁Blue ▁Ch aper on . ▁Art ▁histor ians ▁tend ▁to ▁look ▁to ▁this ▁work ▁to ▁dedu ce ▁how ▁the ▁Isabel la ▁portrait ▁may ▁have ▁looked . ▁The ▁Blue ▁H ood ▁painting ▁is ▁rendered ▁in ▁a ▁mini atur ist ▁scale , ▁pres umably ▁so ▁as ▁to ▁make ▁it ▁easier ▁to ▁ship ▁back ▁to ▁Bru ges , ▁so ▁it ▁is ▁reasonable ▁to