I am trying to get myself into printing using some standards that I think must exist. I have tried google and searching, no luck. I work in centimeters by the way. What would be good standard sizes to use for 35mm and 120 6x6? I figure that finding frames,mounting photos etc. will get a lot easier if I follow standards?
i come from the school of thought that the image determines the print dimenson and use the standard paper sizes allowing the borders to change. Of course this means the windows will/can vary in size, but the outer frame size is usually 14x18 or 16 x20.
Without framing, prints made on the same paper size are stored in a folio, or clam box.
Find out what frames and mounts you can get and then print to fit them.
Just for an example, over here I can find 16x12 frames and a ready made double mount with an image area of roughly 12x8 that fits inside. These are near enough the same aspect ratio as 35mm so there's no cropping.
For color, I send my 35mm to Costco and have them print 12" x 18" prints. They will make 12" x 12" from the 6x6 negatives. Anything larger I take the negative to Golden Color which optically prints to any size that I want. http://goldencolor.com/
The black and white I print any way that I want. I will usually try to get the biggest print out of every sheet of paper.