Oh, OK. Then it's easy, as the display size is fixed. Make sure the image in Word is the same DPI as the book is going to be printed in.
Let's say, you have a 5x5 inch original image. You wish to display it at 3x3 inch in the book itself, after printing. The book will be printed at 300 DPI. Thus:
- The image in the book is 3x3 inch, at 300 DPI. This means it has to be 900x900 pixels on the sides (because 3x300=900.)
- The original 5x5 image needs to end up as a 600x600 pixel image, so you set your scanner to 900 pixels / 5 inch = 180 DPI.
Sometimes, a printing company will recommend to use images that are twice the DPI of the text. (I don't know why: I just know they do that. I've had it happen with printing pictures alongside text.) If they do this, then it would be as such:
- The image in the book is 3x3 inch, and the book is printed at 300 DPI. The image needs to be 600 DPI. Therefore you will need an 1800x1800 image (3x600=1800).
- The original image is 5x5 inch, and to scan it at 1800x1800, you'll need to set the scanner to 1800 pixels / 5 inch = 360 DPI.
And it all fits of course:
If you scan a 5 inch wide image at 360 DPI it will be 1800 pixels wide, and if you then display it at 3 inch, it'll be 1800 pixels / 3 inch = 600 DPI
To make sure you scan the images right, you should contact the printing company and ask them how many DPI they have to be, and then use the method above to caculcate the needed DPI setting for your scanner