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Sensitized Material. Refers to the film and photographic paper that basically composed of emulsion containing silver halides suspended in gelatin and coated on a trasparent or reflective support. Parts of Sensitized Material. Emulsion
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Sensitized Material • Refers to the film and photographic paper that basically composed of emulsion containing silver halides suspended in gelatin and coated on a trasparent or reflective support
Parts of Sensitized Material • Emulsion • Part of the film or photographic paper which contains the silver grains that is sensitive to light • Colored films contain 3 layers of emulsion (blue, green, red) with intervening filters • Anti-Halation Backing • Designed to hold back the light and prevents halation • Base • Support the emulsion
Types of Film(According to Use) • Black and White Film • Usually represented by a prefix or a suffix “pan” or “ortho” and generally used in black and white photography • ex. ortholith, tri x-pan, pan x-plus • Colored Film • Negative Type • Reversal Type
Types of Films(According to Spectral Sensitivity) • Blue Sensitive Film • Sensitive to UV light up to blue color • Orthochromatic Film • Sensitive to UV light up to green color • Panchromatic Film • Sensitive to UV light up to red color (visible light) • Infra-Red Film • Sensitive to all colors and infrared light
Film Speed (Emulsion Speed) • ASA (American Standards Association) • Expressed in arithmetic value system • The higher the number, the more sensitive the film is • ASA 10, 20, 30, 40, 50, 100, 200, 400, 800, 1000 • DIN (Deutche Industre Normen) • Expressed in logarithmic value system • Used in the same principle as the ASA (3 degrees) • DIN 12, 15, 18, 21, 24, 27 30, 33 • ISO (International Standards Organization) • Expressed in combination of ASA and DIN ratings
Photographic Paper • Sensitized material that will record the visible image in the final development and become the photograph
Types of Photographic Paper(According to Emulsion Used) • Silver chloride paper • Used for contact printing • Size of the positive print is the same as the size of the negative used. • Sensitivity to light is low and gives blue-black tones when properly developed • Silver bromide paper • Used in projection, printing and enlarging process. • Most ideal paper used in police photography. • Will give black tones when properly developed
Silver Chlorobromide Paper • Used for both projection and contact printing • Slow emulsion • Variable contract paper • Combines the contrast range in one paper • Uses a special chlorobromide emulsion that produces varying contrast responses upon exposure to different colors of light
Types of Photographic Paper(According to Physical Characteristics) • Weight • Light Weight • Designed for high flexibility and when paper thickness is not of consideration • Intended for purposes which involved folding • Single Weight • Used for small prints or which are needed to be mounted on solid fine details necessary in the production • Used in ordinary photographic purposes • Double Weight • Generally used for large prints because they stand up under rough treatment
Surface Texture • Glossy Paper • Designed for fine details and brilliant image formation • Semi-matte Paper • Obscure fine details • Rough Paper • Used for large prints or where breath rather than detail is necessary
Color • White Paper • Better used in police photography • Cream Paper • Preferred for pictorial effect, portraits, landscapes or where warmth effect is desired • Buff Paper • Paper for tone prints
Types of Photographic Paper(According to Contrast) • Velox No. 0 • Used for printing extremely contrast negative or expremely exposed film • Velox No. 1 • Used for high contrast negative or over exposed film • Velox No. 2 • Used for normal exposed film • Velox No. 3 • Used for negative with weak contrast or underexposed film
Velox No. 4 • Used to provide sufficient contrast to compensate for very thin or weak negatives • Useful imprinting if high contrast is desired • Velox No. 5 • For flat negatives that are unprintable
Chemical Process • Process of making the latent image visible and permanent
Development • The process necessary for reducing the silver halides to form the image • Use either D-76, Dektol or Universal Solution • Elon Hydroquenone • Used as the main developing agent • Stop Bath • Normally composed of water with a little amount dilute acetic acid that serves as a means to prevent contamination between the developer and the acid fixer • Fixation • Process by which al unexposed silver halides are dissolved or removed from the emulsion surface and making the image more permanent • Sodium Thiosulfate (Hypo) • Main fixing agent that dissolves unexposed silver halides
Other Chemicals Used • Acetic Acid and Boric Acid • Serves as neutralizer • Sodium Sulfate • Serves as the preservative • Potassium Bromide (ALUM) • Restrainer or Hardener • Sodium Bicarbonate and Borax Powder • Serves as accelerator
Dark Room Techniques • Dodging • Process of eliminating unwanted portion of the negative during enlarging • Cropping • Process of omitting an object during the process of enlarging and printing • Vignetting • Gradual fading of the image towards the side through skillful adjustment on the dodging board
Dye Toning • Process designed in changing the color of the photograph • Burning-In • Refers to the additional exposure on a desired portion of the negative used for purposes of making a balanced exposure