Since rose petals are a natural, living object and not plastic or stone, there is nothing you can do that will keep the beads the same color as your roses. As the petal dries, the color will change. Like the beautiful red and yellow leaves on trees in autumn that finally turn brown. If you want to know the flowers I have tested to see if peonies will work well - there is a very inexpensive book about this on Amazon called "Rose Beads - Everything you need to know about making beads from your wedding and other special occasion flowers." It has much more information about making rose beads than this page.