The floral preservation process involves the delicate removal of moisture from fresh flowers and leaves. Different methods are used to extract moisture based on the flower and the intended result. I have tried all methods except freeze-drying.
PRESSING: Flowers are pressed in a natural wood flower press for a traditional look. They are often used in framed floral arrangements that reflect a theme or natural setting. A more common use for pressed flowers is in art/crafts such as bookmarks or notecards. Good color retention
SiLICA: For a 3-D presentation, fresh flowers are preserved in silica crystals and then arranged in a glass vase, container, shadowbox, or basket for display. Best color retention
MICROWAVE: Flowers may be dried in a microwave in 15 second increments. It is a slow process since monitoring is necessary. If you wish to have flowers dried quickly, then invest the time and patience needed to microwave them. Use paper towels as a base and cover when microwaving. You may also purchase special presses made specifically for this purpose. Good color retention, but many flowers dry darker.
SLOW-DRYING: Flowers are given just an inch of water and left to dry on their own. Color retention is better than air-drying and there is a bit less wrinkling. Moderate color retention.
AIR-DRYING: There are many flowers that do well when air-dried. Roses are usually place upside down so the petals do not fall off as they dry. They tend to fall on themselves rather than off. When dry, they can be placed upright. Other flowers do just fine sitting in vase and drying! Colors often dry darker and flowers become quite wrinkled and brittle.