Copyright Question...

I know copyright is a very complicated and touchy area to address. My question is copyright issues with quilting and quilt blocks to be specific.

I want to start a section of my blog with little tutorials on how to make certain quilt blocks. I want to show how to make the simple older blocks that are not copyrighted. I read some where on the Internet that anything over 95 years old is not copyrighted. Then I read some where on the web that anything before 1978 is ok...such a confusing topic.

Does any one know the best source, book or website for dating and copyrighting quilt blocks. I know Barbara Brackman has a book and a site, but I need a site with dates of the blocks, so I know that I can use it without any copyright infringements.

I also wanted to know how current designers copyright quilt patterns using certain blocks. Seems like you see the same block or pattern and it's just arranged differently in the quilt. Does that little change of sashing, borders, fabric, placement, size etc constitute enough of a change to call it a "different pattern"

Any help would be appreciated,
~Karen~