Frame size and borders.

I am wondering has anybody got ideas on what the ratio size that I should use for my mount border and frame in relation to the image size.I print images from light room in A2 A3 A3+ and A4 but I think that if I use an aspect ratio based on the golden section that the prints would look more balanced.

That is decided every day when one takes an image to the framers. Its a matter of taste in my opinion. As for me, I like a wide mat and perfer gallery white mats and gallery frames. But sometimes the image looks better with a much larger mat and frame, sometimes no mat at all and a flat, frameless/minimal frame is better. You might do a web search or drop by your local bookstore/library and look over a book on framing. I know there are standards framers use for most images.

Thanks for that I know that taste instinct and a good eye are all part of the selection process and I also notice that those very same attributes are the reason so many images are so badly framed.So I believe myself that the solution to this one is mathematical as I am inclined towards the idea that the one who measures rules.I have worked out a ratio method for doing this and I was hoping maybe somebody else out there has already used a ratio method.

What method are you using?