Hi, well a lovely day here, and I had time for sorting stamps and a visit to the Stamp Arcade in Mong Kok. A very enjoyable day.  I found a few of these and when checking saw the differences, which I hope you can see. Always worth looking and having a catalogue nearby to check why the difference. These were issued in 1965  for the Churchill  Comemoration. The left hand stamp is SG 661 and the other is SG 661a.

SG 661 was printed using the REMBRANDT machine, and the other was printed using the Timson machine. the major difference is that SG 661 has a lack of shading detail on Churchill's portrait. The Timson machine printing shows more detail on Churchill's portrait with furrow on forehead, his left eyebrow is fully drawn and there is more shading on his cheek. Also, the Queen's portrait is lighter and sharper. This is a reel fed two colour12-inch wide rotary machine and the differences in impression are due to the greater pressure applied by this printing machine. The following is a Timson machine

To read more about this and other printing machines of the 1960's I hope you enjoy this link http://deltastamps.com/Fact14LSD1960.htm

have a great weekend.... Michael

www.cddstamps