This is how the template for such a frame looks like. Please note, that not the absolute size but the ratios are important for this explanation. Using this template you can make a frame that has borders of equal width and height. The parts to be removed are marked in red, the inner bold rectangle shows the part of a picture that will be visible.

So, first measure a picture you'd like to frame. Add ten times the width of the frame border to both dimensions. For example, if your picture is 10x15cm with 1cm wide border, the resulting size would be 10+10*1 by 15+10*1 = 20x25cm. Draw a rectangle according to your calculations and cut it out. Then measure and mark the folding lines and corners as the template shows. Start measuring from the outer edges of the paper. Cut away the parts shaded with red.

To remind you, only the relative size of the parts is important. That is, if you want to make wider (and higher) borders, just multiply each number in the picture by the same factor.

Score the folding lines marked with blue dashes on the template. Use a special scoring tool, a thin embossing tool or simply a stick with rounded tip. Then fold as shown in the picture.

If you already have a picture to frame, glue it down now and then start assembling your paper frame.

Insert an end of each side border into its neighbor's end at the corners, one by one, like shown in the photos.

Generally, no adhesive is needed, but you may want to secure the frame with a small amount of glue.

If you want to make a frame with wide borders, the template will look like this (pay attention to the proportions):

And this one is for a deep frame, where the border's height is greater than its width.

The same principles apply for these templates as well: if you want another size, just multiply the numbers by a constant factor.

http://increations.blogspot.com/