Wratten number

Wratten number

Wratten numbers are a labeling system for optical filters, usually for photographic use.

They are named for the man who founded the first company, Frederick Wratten, a British inventor. Wratten and partner C. E. K. Mees sold their company to Eastman Kodak in 1912, and Kodak continued to produce "Wratten Filters" for decades. Even now, as of 2006, Wratten filters are still produced by Kodak, and sold under license through the Tiffen corporation.

Wratten filters are very much an active part of observational astronomy.

Filters made by various manufacturers may be identified by Wratten numbers but not precisely match the spectral definition for that number. This is especially true for filters used for aesthetic (as opposed to technical) reasons; for example, an 81B Warming Filter is a filter used to slightly "warm" the colors in a color photo, making the scene a bit less blue and more red. Many manufacturers make filters labeled as 81B which do similar but not exactly the same filtering of light, according to that manufacturer's idea of how exactly it is best to warm a scene, and depending on their manufacturing techniques. Some manufacturers use their own designations to avoid this confusion, for example Singh-Ray has a warming filter which they designate A-13, which is not a Wratten number. Filters used for printing press color separation or scientific photography tend to have less variation.

Reference Table

The commonly available numbers and some of their uses include:

External links

* [http://www.filmcentre.co.uk/faqs_filter.htm FAQs for DPs: filters]
* [http://www.geocities.com/cokinfiltersystem/color_corection.htm Filters table]


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • Wratten 47B — is the model number of a type of translucent blue plastic used in optics. Manufactured by Kodak, it is most commonly used to calibrate video monitors while using SMPTE color bars, although it also has less common applications in photography and… …   Wikipedia

  • Filter factor — In photography, filter factor refers to the multiplicative amount of light a filter blocks.Converting between filter factors and stopsThe table below illustrates the relationship between filter factor, the amount of light that is allowed through… …   Wikipedia

  • Color gel — See also: Photographic filter Many color gels organized, some in gel frames A color gel or color filter (UK spelling: colour gel or colour filter), also known as lighting gel or simply gel, is a transparent colored material that is used in… …   Wikipedia

  • Gabapentin — Systematic (IUPAC) name 2 [1 (aminomethyl)cyclohexyl]acetic acid …   Wikipedia

  • Walter Godfrey — Infobox Architect name=Walter Hindes Godfrey nationality=English birth date=1881 birth place= death date=1961 death place= practice name=Carden and Godfrey; Wratten Godfrey significant buildings=Burford Priory, Oxfordshire The Temple Church… …   Wikipedia

  • Photographic filter — Four photographic filters. Clockwise, from top left, an infrared hot mirror filter, a polarising filter, and a UV filter. The larger filter is a polariser for Cokin style filter mounts. In photography and videography, a filter is a camera… …   Wikipedia

  • 1994 Scotland RAF Chinook crash — The memorial on the Mull of Kintyre to the victims Accident summary Date 2 June 199 …   Wikipedia

  • Chatham House Grammar School — CHGS redirects here. For the radio station originally known as CHGS, see CJRW FM. For the non governmental organization formally known as the Royal Institute of International Affairs, see Chatham House. Chatham House Grammar School Chatham House… …   Wikipedia

  • Collodion process — An old deteriorated wet plate featuring Theodore Roosevelt The collodion process is an early photographic process. It was introduced in the 1850s and by the end of that decade it had almost entirely replaced the first practical photographic… …   Wikipedia

  • Infrared photography — Top: tree photographed in the near infrared range. Bottom: same tree in the visible part of the spectrum …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”