File:The American annual of photography (1918) (14594729937).jpg

Identifier: americanannualof1918newy (find matches)
Title: The American annual of photography
Year: 1918 (1910s)
Authors:
Subjects: Photography
Publisher: New York : Tennant and Ward
Contributing Library: Harold B. Lee Library
Digitizing Sponsor: Brigham Young University

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
Figure 4. Flowers should be selected which have just opened or aboutto open. Objection is frequently raised that delicate wood-land blossoms will wilt before they can be brought home, butthirty years of experience has shown me that this difficulty islargely specious. Most writers on flower photography dwellmuch on the danger of the floral organs moving slightly andspoiling the negative. In my personal experience, where theflowers are laid on a sheet of plate glass, I have found thisdanger wholly imaginary. 196
Text Appearing After Image:
Figure 5. Panchromatic plates are, of course, a sine qua non. I usethe well known Wratten and Wainwright plates, but there areother excellent brands on the market. A panchromatic plateis a plate the emulsion of which has been treated with anihnedyes so that it is rendered sensitive to all the colors of the solarspectrum ; for example, the addition of a very small quantityof cyanin blue to an emulsion causes it to become very sensi-tive to red waves of light. The ordinary plate is sensitive chiefly to violet and bluerays, a trifle to green, and not at all to yellow and red. Inother words, it sees the colors as the human eye sees themwhen it looks through blue glass. Blue glass absorbs all the 197 rays of light except the blue which pass through it. But theordinary plate is not only chiefly sensitive to blue waves oflight, but it is extremely over-sensitive to them; and thus itresults that it shows blue as white and yellow, orange and redas black, whereas blue should appear as a medium

Note About Images