I would like to submit this "Key" for describing perforation errors.
A few of examples might be;
Missing D3 perf. = The center horizontal perforation is missing
Double Line DR3 perf. = The diagonal right perforation is doubled
Extra line between H4/H5 = An extra stray line of perforations towards bottom of sheet
Extra line of perfs at H0 = An extra horizontal row of perforations at top of sheet.
As I'm looking at the sheet drawing, I see 5 possible complete octagons and several partials.
I'm still developing a color error list key. Here are some I've encountered recently;
A missing color - such as black
A different blend or shade of color - A greenish overall tint
Miss-registered printing plates leading to shadows and/or blurry image
I also have encountered a printed date error - on 25c - 2008 sheet - one date is 2007 & 1 is 20087.
Please submit any thoughts on description "Error key" ideas.