This decorating icing is very stiff and hardens as it dries.
Place egg whites in the bowl of an electric mixer and beat using the whisk attachment until frothy. Add 1/4 cup of the sugar and mix well. Gradually add the remaining 3 3/4 cups sugar, beating on low speed and scraping down the sides.
Increase the speed to high and continue to beat the mixture until soft peaks form, about 5 minutes. At this stage, the icing will be very thick. Add water, a few drops at a time, to thin it to the consistency appropriate for the kind of decorating you are doing. As a rule, the icing should be stiffer for lettering, more malleable for making petals -- but you will need to experiment to find the consistency that works best for you. Store icing at room temperature in an airtight glass or metal container. It should be used within two days.
Raw eggs should not be used in food prepared for pregnant women, babies, young children, the elderly, or anyone whose health is compromised.