I use sizing on light colors and starch on everything else. I'm not patient enough to wait for the starch to dry most of the time and any scorching will really show on light fabrics. It seems that even when I do wait for the starch to "set"--my iron will decide to self-clean itself on light fabric. I need a new, non-steam, non-auto shut off iron! Anyway--I use both. It just depends on what color the fabric is and I always iron light fabric from the back side.