▁paper . ▁At ▁the ▁post ▁office ▁counter , ▁only ▁the ▁four ▁separated ▁printing ▁sheets ▁are ▁sold . ▁Therefore , ▁the ▁sheet ▁of ▁st amps ▁is ▁also ▁called ▁a ▁counter ▁sheet ▁or ▁p ane , ▁though ▁impro per ly ▁called ▁a ▁sheet ▁of ▁st amps . ▁ ▁Gut ters ▁ ▁The ▁empty ▁fields ▁connecting ▁the ▁single ▁counter ▁sheets ▁are ▁called ▁gut ters . ▁Norm ally ▁they ▁are ▁separated ▁in ▁the ▁middle ▁after ▁printing ▁in ▁order ▁to ▁obtain ▁four ▁counter ▁sheets . ▁The ▁half ▁empty ▁fields ▁or ▁gut ters ▁then ▁form ▁the ▁edge ▁of ▁the ▁sheet . ▁However , ▁from ▁many ▁issues , ▁un separ ated ▁gut ters ▁with ▁connected ▁st amps ▁of ▁the ▁neighbour ing ▁sheets ▁come ▁on ▁the ▁market ▁( st amp ▁- ▁empty ▁field ▁- ▁stamp ). ▁These ▁gut ters ▁may ▁be ▁either ▁empty ▁or ▁printed , ▁if ▁printed ▁edges ▁were ▁intended . ▁ ▁The ▁phil atel ist ▁makes ▁a ▁distinction ▁between ▁horizontal ▁and ▁vertical ▁gut ters . ▁A ▁specific ▁characteristic ▁of ▁the ▁gut ters ▁is ▁the ▁heart ▁of ▁the ▁printing ▁sheet , ▁where ▁all ▁four ▁pan es ▁are ▁connected . ▁Gut ters ▁and ▁hearts ▁are ▁very ▁popular ▁with ▁collect ors ▁and ▁reach ▁high ▁catalog ▁prices , ▁especially ▁for ▁classic ▁issues . ▁ ▁T ête - b ê che ▁ ▁Single ▁counter ▁sheets ▁do ▁not ▁always ▁have ▁to ▁be ▁separated ▁by ▁empty ▁fields . ▁Iss ues ▁which ▁were ▁not ▁intended ▁to ▁have ▁edges ▁were ▁naturally ▁manufact ured ▁without ▁empty ▁fields . ▁To ▁be ▁able ▁to ▁distinguish ▁between ▁the ▁single ▁sheets ▁better ,