Historical clue formulations

• B-___ (rare blood type, informally) — 2025-03-31
• Darkroom item, in brief — 2022-07-31
• -: Abbr. — 2020-12-17
• -: Abbr. — 2020-11-26
• Less than zero: Abbr. — 2020-08-17
• Below zero: Abbr. — 2020-02-09
• Below zero: Abbr. — 2019-11-20
• -: Abbr. — 2019-10-22
• Blood type abbr. — 2019-08-24
• Abbr. in many blood type names — 2018-10-28
• Like one end of a battery: Abbr. — 2018-09-17
• Blood-typing abbr. — 2018-07-21
• Original of an old photo, informally — 2018-05-22
• Blood type modifier, for short — 2018-03-04
• Like rarer blood types: Abbr. — 2017-01-18
• Bit of blood-typing shorthand — 2016-06-10
• -: Abbr. — 2015-11-05
• -: Abbr. — 2015-03-15
• Follower of A, B or AB, informally — 2014-01-19
• Like the rarer blood types, typically: Abbr. — 2013-06-25
• Below zero: Abbr. — 2013-05-27
• Photog's master — 2012-04-05
• What "-" may mean: Abbr. — 2011-08-23
• Like some ions: Abbr. — 2009-08-19
• Less than zero: Abbr. — 2009-06-01
• Minus: Abbr. — 2009-04-22
• Photo image, briefly — 2008-03-24
• Photog's image — 2006-10-22
• One pole: Abbr. — 2006-01-22
• -: Abbr. — 2004-10-17
• Blood-typing abbr. — 2004-04-01
• Photo envelope enclosure, for short — 2002-08-06
• Darkroom master: Abbr. — 2002-07-12
• Photog's item — 2002-04-07
• Kind of charge: Abbr. — 2001-11-03
• Like some blood types: Abbr. — 2001-09-02
• Master of photog. — 2001-01-07
• Photog's item — 2000-04-26
• Item in a photog's file — 1999-12-23
• A photog saves it — 1999-10-04
• Master of photography: Abbr. — 1999-07-17
• Like certain battery terminals: Abbr. — 1999-07-04
• Item in a photog's file — 1999-05-08
• Kind of no. — 1999-04-10
• Not pos. — 1997-04-14
• Where black is white, for short? — 1997-02-09
• Reprint necessity: Abbr. — 1996-12-12
• Reverse image, for short — 1996-11-11
• Reverse image, for short — 1996-09-14
• Photographic image, for short — 1995-08-02