Safelight
A safelight is a light source suitable for use in a photographic darkroom. It provides illumination only from parts of the visible spectrum to which the photographic material in use is nearly, or completely insensitive.
Design
A safelight usually consists of an ordinary light bulb in a housing closed off by a coloured filter, but sometimes a special light bulb or fluorescent tube with suitable filter material or phosphor (in fluorescent tubes) coated directly on the glass is used in an ordinary fixture.
Differently sensitised materials require different safelights. In traditional black-and-white photographic printing, photographic papers normally are handled under an amber or red safelight, as such papers typically are sensitive only to blue and green light. Orthochromatic papers and films are also sensitive to yellow light and must be used only with a deep red safelight, not with an amber one.[1] Panchromatic films and papers, nominally sensitive to the entire spectrum, sometimes have a region of minimum in their range of sensitivity that allows the careful use of safelight confined to that part of the spectrum. For example, Kodak Panalure panchromatic paper is tolerant of limited exposure to light filtered through a Kodak 13 Safelight Filter.[2] Other panchromatic materials must be handled only in total darkness.
Many photosensitive materials used in technical and industrial applications, such as photoresist, are sensitive only to blue, violet, and ultraviolet light and may be handled under a brighter yellow safelight. Low-pressure sodium vapour lamps sometimes are used in larger industrial darkrooms. They emit nearly monochromatic light at 589 nm (yellow), to which the materials are insensitive; as a result they can be extremely bright while still "safe".[citation needed]
The word safe in safelight is relative, as in most cases, a sensitised material eventually will be affected by its safelight if exposed to it for an extended length of time.[3]
See also
- Photographic processing
- Purkinje effect
References
- ^ Langford, Michael (2000), Basic Photography (Seventh Edition), Oxford: Focal Press, p. 237, ISBN 0-240-51592-7
- ^ Kodak Professional Panalure Select RC Paper, Rochester, New York, U.S.A.: Eastman Kodak Company, June 2005, p. 1
- ^ "Fact Sheet: SAFELIGHT FILTERS AND DARKROOM LAMP" (PDF). Ilford. October 2002. Archived from the original (PDF) on 2011-07-23. Retrieved 2011-08-02.
- v
- t
- e
- Camera
- Darkroom
- enlarger
- safelight
- Drone
- Film
- Filter
- Flash
- Lens
- Manufacturers
- Monopod
- Movie projector
- Slide projector
- Tripod
- Zone plate
- 35 mm equivalent focal length
- Angle of view
- Aperture
- Backscatter
- Black-and-white
- Chromatic aberration
- Circle of confusion
- Color balance
- Color temperature
- Depth of field
- Depth of focus
- Exposure
- Exposure compensation
- Exposure value
- Zebra patterning
- F-number
- Film format
- Film speed
- Focal length
- Guide number
- Hyperfocal distance
- Lens flare
- Metering mode
- Perspective distortion
- Photograph
- Photographic printing
- Photographic processes
- Reciprocity
- Red-eye effect
- Science of photography
- Shutter speed
- Sync
- Zone System
- Abstract
- Aerial
- Aircraft
- Architectural
- Astrophotography
- Banquet
- Candid
- Conceptual
- Conservation
- Cloudscape
- Documentary
- Eclipse
- Ethnographic
- Erotic
- Fashion
- Fine-art
- Fire
- Forensic
- Glamour
- High-speed
- Landscape
- Nature
- Neues Sehen
- Nude
- Photojournalism
- Pictorialism
- Pornography
- Portrait
- Post-mortem
- Ruins
- Selfie
- Social documentary
- Sports
- Still life
- Stock
- Straight photography
- Street
- Toy camera
- Underwater
- Vernacular
- Wedding
- Wildlife
- Afocal
- Bokeh
- Brenizer
- Burst mode
- Contre-jour
- Cyanotype
- ETTR
- Fill flash
- Fireworks
- Harris shutter
- High-speed
- Holography
- Infrared
- Intentional camera movement
- Kirlian
- Kite aerial
- Lo-fi photography
- Long-exposure
- Luminogram
- Macro
- Mordançage
- Multiple exposure
- Multi-exposure HDR capture
- Night
- Panning
- Panoramic
- Photogram
- Print toning
- Pigeon photography
- Redscale
- Rephotography
- Rollout
- Scanography
- Schlieren photography
- Sabattier effect
- Slow motion
- Stereoscopy
- Stopping down
- Strip
- Sun printing
- Tilt–shift
- Time-lapse
- Ultraviolet
- Vignetting
- Xerography
- Zoom burst
- Diagonal method
- Framing
- Headroom
- Lead room
- Rule of thirds
- Simplicity
- Golden triangle (composition)
processing
- Category
- Outline
This photography-related article is a stub. You can help Wikipedia by expanding it. |
- v
- t
- e