Why Imperf S And Perfs Of The Same Stamp?

I am wanting to expand my plate block collection into the older issues. In my research I am noticing many issues with perfs and non-gummed imperf s varieties. What is the purpose of issuing a non-gummed imperf and perf of the same stamp? I don't see any practical purpose for the imperf s as general postage. I don't know what is the intended use. Any thoughts to clear up my confusion would be appreciated.

Are you referring to the James Farley follies?


http://www.stampsmarter.com/1847usa...Follies.html

Hello, I've noticed, by looking at online auctions, that there are imperfs in older issues as well as the Farley follies. Scott# 531, 532 & 575 just to name a few. I was wondering if they were gummed and what is the purpose of printing them without perforations. Was it due to the different types of printing processes? Is there any recommendation as to what to collect, imperfs vs. perfs, or is it just a matter of personal preference. Thank you for your comments.

Imperforate US stamps in the 1908 to 1926 period were supplied to vending and affixing machine companies to be privately perforated and stripped into coils for use in affixing machines for commercial mail and vending machines for consumers. The Bureau of Engraving and Printing also issued coils which eventually supplanted private perforations when low-denomination sheet stamp production was switched to the rotary press. The first imperforate rotary press sheet stamp, Scott 631, issued in 1926, was found unsuitable for use by the vending and affixing machine companies, effectively ending production of private coils.

More info
http://www.stampsmarter.com/1847usa...tePerfs.html
Don

Well, that answered that. Thank you so much for the information and the link into that part of postal history.