Cancels On My W/F's

So I got a little bored identifying my W/F hoard so I decided to break out the cancels. Small example below (I will post the register cancels later) and I have thousands of these.

Looks like I have a lot of "1's) but there is a smattering of others. Got me interested in learning more....

I am sure there are a few threads on this but what is the best book / resource to ID these?

Most of the postmarks shown are from a "duplex cancel" (see figure 3 in the attached article). The next to the last example on the bottom row with "RMS" refers to Railway Mail Service, typically from an RPO (Railway Post Office):

http://www.linns.com/howto/refreshe...rcourse.aspx

There are couple (second row, center) and last stamp on the page, with a bulls eye cancel. That generally predates the duplex cancel and was used solely as a means to obliterate the stamp to prevent re-use.

Thanks wt! Good article. Is there any collectability for these i.e. should I continue to sort?

Here are a few Register Cancels & some additional RMS and Duplex ones.... comments welcome!

Collectible, yes. Valuable, no. There are many stamp collectors who focus on stamps only; still others who prefer studying only the postmarks. It's a collecting specialty for some. Postmark collecting can make the tedious task of going through a bunch of stamps from pretty much the same issue that much more interesting.

exactly what got me started doing this! Thanks for the comments.

Those are some of my favorite cancels; I have a stockbook full.