Paper Sizes and Aspect Ratios, confusing ?

Hi All,

One of things that causes me a lot of confusion in digital photography is aspect ratios and standard print sizes. I'm sure that for a lot of people out there this particular subject doesn't cause them a problem but, sadly for me, it does.

My D300S sensor is a 2:3 aspect ratio so if I want to send one of my images for printing which standard size paper can I print to without getting the image cropped ? 

Most printers print at A4 and a lot of photo paper manufacturers make paper to fit the A4 printer. However an image generated by a 2:3 sensor doesn't fit exactly on an A4 sheet therefore I can either print the image smaller than A4 or risk losing some of the image if I print to fit A4. 

Trying to visualise how much will get lost is almost as big a problem as trying to work out the ratios in the first place.

Thankfully my son Ben is, unlike his dad, a bit of a whizz when it comes to maths and ratios. So after some long discussions and a lot of patience on his part I finally got me head around sizes and ratios. My problem is that I tend to forget very easily. 

So in a slack moment (very rare at this location let me tell you!) I decided to create an image in Photoshop that, when printed on an A4 sheet would give the viewer (me) an instant idea of what would fit to what. 

The images is below and if you save it to your hard drive and print it to an A4 printer you may also find the visual reference useful.

Please feel free to give it a go. Apologies if it doesn't work on your printer.