Film types and storage Devices

Film types and storage devices 

Photographic film

Undeveloped Arista black-and-white film

Photographic film is a strip or sheet of transparent plastic film base coated on one side with a gelatin emulsion containing microscopically small light-sensitive silver halide crystals.The sizes and other characteristics of the crystals determine the sensitivity, contrast and resolution of the film.

Light is neither a wave nor a particle, but has properties of both. Light can be focused like a wave, but its energy is distributed in discrete packets called photons. The energy of each photon is inversely related to the wavelength of the light -- blue light is the most energetic, while red light has the least energy per photon of exposure. Ultraviolet light (UV) is more energetic, but invisible to human eyes. Infrared light is also invisible, but if it is strong enough our skin detects it as heat.

It is the energy in each photon of light that causes a chemical change to the photographic detectors that are coated on the film. The process whereby electromagnetic energy causes chemical changes to matter is known as photochemistry. By carefully engineering materials, they can be chemically stable until they are exposed to radiation (light). Photochemistry comes in many different forms. For example, specially formulated plastics can be hardened (cured) by exposure to ultraviolet light, but exposure to visible light has no effect. 

                                  http://electronics.howstuffworks.com/film.htm 

Color

Experiments with color photography began almost as early as photography itself, but the three-color principle underlying all practical processes was not set forth until 1855, not demonstrated until 1861, and not generally accepted as "real" color photography until it had become an undeniable commercial reality in the early 20th century. Although color photographs of good quality were being made by the 1890s, they required special equipment, long exposures, complex printing or display procedures and highly specialized skills, so they were then exceedingly rare.

The first practical and commercially successful color "film" was the Lumière Autochrome, a glass plate product introduced in 1907. It was expensive and not sensitive enough for hand-held "snapshot" use. 

Storage device - memory card

A memory card or flash memory card is a solid-state electronic flash memory data storage device used with digital cameras, handheld and Mobile computers, telephones, music players, video game consoles, and other electronics. 
Nowadays, most new PCs have built-in slots for a variety of memory cards; Memory Stick, CompactFlash, SD, etc. Some digital gadgets support more than one memory card to ensure compatibility.there are many types of storage memory card Secure Digital (SD), Mini Secure Digital (miniSD), Compact Flash (CF) Type 1, Compact Flash (CF) Type 2 to several other more. 

Secure Digital (SD):

A widely used format of small size and available in high capacities. SD is being used more and more in compact digital cameras and other portable electronics due to its small size. Many notebook computers have built in SD card slots to allow easy data transfer without the need for adaptors. At this time, the SD card format looks to be the most likely to become a standard, and is probably the safest bet as far a future support goes. A locking tab is provided to prevent accidental erasure.

Secure Digital card (SD)

Bibliography 

http://www.whatdigitalcamera.com/buying-advice/technology_guides/understanding-memory-cards/