One Penny Red Issues.
Issued 1914 Die I single wmk perf 14.2 single line ~ 2 shade groups.
Issued 1914 ~ 1921 Die I single wmk smooth paper perf 14.25 X 14 comb ~ 27 shade groups
Issued 1916 ~ 1918 Die I single wmk rough paper perf 14.25 X 14 comb ~ 20 shade groups
Issued 1918 ~ 1919 Die I Lm wmk perf 14.25 X 14 comb ~ 8 shade groups
Issued 1918 ~ 1920 Die III single wmk perf 14.25 X 14 comb ~ 4 shade groups.
Note: Die III has shading around the head even. " One Penny" short, thick & uneven. An extra smaller outer white oval from emus back to roo's head.

Image: Block one: 1st stamp "wattle line" right hand wattles on angle pointing to crown.
2nd stamp Die II ~ it is not a Die; it is a constant printing flaw. In the left value tablet bottom mid to right a small white spur can be seen.
3rd stamp "perperforation misalignment" must be 2mm + cut into the print of the stamp. This example is only 1.5mm. Rough papaer example.
4th stamp flaw under neck.

Block 2:1st stamp "thin G", 2nd stamp "roo's tongue", 3rd stamp saddle on emu,4th stamp RA joined

Third block:1st stamp "dot before 1",2nd stamp secret mark found below the "N" in one. A "V" shaped nick in bottom frame,3rd stamp "N" of one,4th stamp "PENAVY".
A Mr Blogg in the 1920s docummented the cream of 2 million penny reds & described 422 shades.
The lack of red ink from Germany during WWI led the Australian Penny Red Printer to mix inks. Blues, purples, pinks, yellows, brown etc. These caused many shade groups. Maybe we can call Mr Blogg the first penny red Bloggist. KGV