| 词条 | Sensitometry |
| 释义 |
Sensitometry is the scientific study of light-sensitive materials, especially photographic film. The study has its origins in the work by Ferdinand Hurter and Vero Charles Driffield (circa 1876) with early black-and-white emulsions.[1][2] They determined how the density of silver produced varied with the amount of light received, and the method and time of development. DetailsPlots of film density (log of opacity) versus the log of exposure are called characteristic curves,[3] Hurter–Driffield curves,[4] H–D curves,[3] HD curves,[4] H & D curves,[5] D–logE curves,[6] or D–logH curves.[7] At moderate exposures, the overall shape is typically a bit like an "S" slanted so that its base and top are horizontal. There is usually a central region of the HD curve which approximates to a straight line, called the "linear" or "straight-line" portion; the slope of this region is called the gamma. The low end is called the "toe", and at the top, the curve rounds over to form the "shoulder". At extremely high exposures, the density may come back down, an effect known as solarisation. Different commercial film materials cover a gamma range from about 0.5 to about 5. Often it is not the original film that one views but a second or later generation. In these cases the end-to-end gamma is approximately the product of the separate gammas. Photographic paper prints have end-to-end gammas generally somewhat over 1. Projection transparencies for dark surround viewing have end-to-end gamma approximately 1.5. A full set of HD curves for a film shows how these vary with developer type and time.[8] See also
References1. ^Hurter, Ferdinand & Driffield, Vero Charles (1890) Photochemical Investigations and a New Method of Determination of the Sensitiveness of Photographic Plates, J. Soc. Chem. Ind. May 31, 1890. 2. ^{{cite journal|last1=Mees|first1=C. E. Kenneth|title=L. A. Jones and his Work on Photographic Sensitometry|journal=Image, Journal of Photography of George Eastman House|date=May 1954|volume=III|issue=5|pages=34–36|url=http://image.eastmanhouse.org/files/GEH_1954_03_05.pdf|accessdate=15 July 2014|publisher=International Museum of Photography at George Eastman House Inc.|location=Rochester, N.Y.|deadurl=yes|archiveurl=https://web.archive.org/web/20140720233757/http://image.eastmanhouse.org/files/GEH_1954_03_05.pdf|archivedate=20 July 2014|df=}} 3. ^1 {{cite book | title = Advanced University Physics | author = Stuart B. Palmer and Mircea S. Rogalski | publisher = Taylor & Francis | year = 1996 | ISBN = 2-88449-065-5 | url = https://books.google.com/books?id=TF6Igz5lJLgC&pg=PA349&dq=hurter-driffield-curve+h-d-curve&lr=&as_brr=3&ei=songR5KAJIWusgOWlPQU&sig=FgC6_uAklssPUpNaUyyr2lS0hNk }} 4. ^{{cite book | title = Multielement Detection Systems for Spectrochemical Analysis | author = Kenneth W. Busch and Marianna A. Busch | publisher = Wiley-Interscience | year = 1990 | ISBN = 0-471-81974-3 | url = https://books.google.com/books?id=9H0W1J-Rku4C&pg=PA339&dq=h-d-curve+density&lr=&as_brr=3&ei=qYzgR46lBYbosQOrzpgV&sig=_kTikTsCw2-7B8XvfO6y73rmTkc#PPA341,M1 }} 5. ^{{cite book | title = Principles of Radiographic Imaging: An Art and a Science | author = Richard R. Carlton, Arlene McKenna Adler | publisher = Thomson Delmar Learning | year = 2000 | ISBN = 0-7668-1300-2 | url = https://books.google.com/books?id=oA-eBHsapX8C&pg=PA318&dq=h%26d-curve+density&lr=&as_brr=3&ei=to3gR5GCLI6eswOs98kV&sig=s_vE4f5PMysrrCtgM7_HJrsRu_Y }} 6. ^{{cite book | title = Remote Sensing Geology | author = Ravi P. Gupta | publisher = Springer | year = 2003 | ISBN = 3-540-43185-3 | url = https://books.google.com/books?id=74T8X1zqgF4C&pg=PA62&dq=d-log-e-curve+density&lr=&as_brr=3&ei=eY7gR4qWEILusgO60YCrAg&sig=MBImrU6KwlZwoV29Xl1PywwEINQ }} 7. ^{{cite book | title = The Focal Encyclopedia of Photography | author = Leslie D. Stroebel and Richard D. Zakia | publisher = Focal Press | year = 1993 | ISBN = 0-240-51417-3 | url = https://books.google.com/books?id=CU7-2ZLGFpYC&pg=PA794&dq=d-log-h-curve+density&lr=&as_brr=3&ei=BI_gR6qIGIiUtgOY5tEV&sig=wfoH3l-C-AKifDLLObbnYn7FrHg }} 8. ^1 {{cite web | url = http://www.kodak.com/global/en/professional/support/techPubs/f4017/f4017.jhtml | title = KODAK PROFESSIONAL TRI-X 320 and 400 Films |date = May 2007 |publisher=Eastman Kodak Company|format=PDF }} External links
2 : Optical metrology|Science of photography |
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