Step 1 :Let the original side length be \(s\), then the new side length is \(\frac{s}{2}\).
Step 2 :Calculate the area of the original square and the new square: \(s^2\) and \(\left(\frac{s}{2}\right)^2\).
Step 3 :Find the ratio between the new area and the old area: \(\frac{\left(\frac{s}{2}\right)^2}{s^2}\).
Step 4 :Simplify the ratio: \(\frac{\frac{s^2}{4}}{s^2}\) = \(\frac{1}{4}\).
Step 5 :\(\boxed{1:4}\) is the ratio of the new area to the old area.