I have been collecting plate blocks for a while, and I just discovered a great resource. The Israel Plate Block Society Journal. I am not sure if the society is still in existence, as my e-mails to the president have gone unanswered, but I was able to borrow the archives of the journal from the SIP library. The archives contain almost 1200 pages of material, starting with the first issue in 1978, and ending in mid-2005. So far, I have made it through over a thousand pages, extracting about 250 different items that I need to add or modify in my database. The research done was incredibly detailed. Most issues are listed, with the number of panes per printing sheet, number of printing runs, and information on how to tell where a given plate block came from.
So, given all this information, what should I collect. My current plan is to collect all plate blocks that have a visible difference. For example, the four different perforation types, or different colors of plate number, or different printing dated. For the shekel issue only, I am trying to collect each plate and each printing run, but this is only because I have a fairly comprehensive collection already. I will not be going back and trying to collect the various pane and printing runs for other issues. Otherwise, I could go on forever.
One last thing. I said I discovered this resource. The discovery was made on E-bay. I saw a lot for sale of the back issues of the journal. I lost out, as the lot went for more than $75. I then went to the APRL to see if they had a copy that I could borrow, and I sent a request to the SIP librarian at the same time. Both libraries had a copy, and it was cheaper to borrow it from the SIP, so I did that. Had the lot never appeared on E-bay, I would not even know this resource existed.