H and D speed

\ ¦āchənˈdē- \

Definition of H and D speed

: a number indicating the sensitivity of a photographic emulsion determined by the method of Hurter and Driffield

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History and Etymology for H and D speed

after Ferdinand Hurter and Charles Driffield fl 1890

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Cite this Entry

“H and D speed.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/H%20and%20D%20speed. Accessed 3 Dec. 2020.

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