Scans are better. Good ones, so we can see details. But if you want to take a crack at it yourself, try these if you can't get a Scott Specialized Catalog for US (I assume you are talking about US).
http://www.theswedishtiger.com/ID.html (Here, remember to click on the design that it looks like. Don't look to match denominations).
http://www.1847usa.com/SiteMap.htmWhen checking stamp type details, check as many individual details as possible because some stamps carry characteristics of more than one type sometimes.
Hope this helps
-IBFS