im a bit confused by all this ratio talk its the first time ive printed . ive got photoshop thanks
Ratio, as far as photos go, is just an expression used to compare the length of the two sides of the picture.
For a modern dslr, the long side is 1.5x the length of the short side. For ease of reference, and to remove the decimal place, this is rounded up and expressed as 3:2 (3 being 1.5x bigger than 2). Thus it can be seen that pictures that measure 6x4, 9x6, 12x8, 24x16, 30x20 etc all have the same ratio, and can all be used to print the images straight from your camera without cropping, because they are the same ratio as the pictures produced by your camera.
The problem comes when we want to make prints that do not share this 3:2 ratio. Common sizes that do not fit this ratio are typically 7x5 and 10x8. If you want to print at 7x5, you will lose 1/2 inch off the long side, so it is best to crop the image yourself, otherwise the printing lab may chop off part of the picture that you want to keep.
10x8 is even worse, as it is a much 'squarer' format. Should you ever wish to print at 10x8 you have two options. You can crop the long side of your image - the closest native size straight from camera is 12x8, so you are going to lose 2 inches from the long side to get it to fit 10x8. The alternative is to print so that the long side fits the 10", but this will leave white borders at the top and bottom, as the short side of your picture will only measure 6.7", not the 8" required to fill the paper.