Soft gel food color is a little looser than paste gel food color. Soft gel food color works best for painting icing sheets because it has just enough moisture to glide on evenly with a paint brush, but not so much that it will cause the icing sheet to soften. Edible icing sheets fresh from the resealable package should smell sweet and have some bend to them. If your icing sheet is rigid and hard, then it has been exposed to air and will be too brittle to use.