HF The History of Photography 600pág

The daguerreotype 73
Fig 5 Daguerreotype ouifit, vignette from 'Daguerreotypie' by]. Thierry, 1847
Daguerre's epoch-making invention was as yet far from perfect, and it was left to
other scientists, American, English, French, and Austrian, to speed up the process and
make it applicable to portraiture-the great desideratum.
The daguerreotype suffered from inherent disadvantages and for this reason the
process must be regarded as a cul-de-sac :
(a) The mirror-like surface of the silvered copper plate makes the picture difficult
to see.
(b) The picture, being a direct positive, was laterally reversed.
(c) Being on a plate of solid metal, it could not be used as a negative to print
copies ; each picture was unique. To overcome this, numerous processes were
evolved to convert daguerreotypes into printing plates, but the procedures
were too complicated for general use. (See chapter 44.)
Daguerreotype cameras. Like Niepce, Daguerre used a camera comprising two boxes,
the rear part with the ground-glass sliding within the front part containing the lens.
His experimental cameras were obtained from the same Parisian opticians, Charles
and Vincent Chevalier. From June I 839 he entrusted Alphonse Giroux, a relative of
his wife, with the exclusive manufacture of his cameras, which were expected to
be in great demand. Yet in spite of the fact that they were sent all over the world,
only a few specimens made by Giroux and bearing his guarantee and seal and Pl 3 r
Daguerre's signature seem to have survived. They were fairly large (re!- in. long
when closed and 20 in. long when extended, height 1£.l- in., width 14f in.), for
Daguerre used 6t in. x 8f in. plates. Up to 1841, every camera was fitted with a
meniscus or a plano-convex lens, having a focal length of 16 in. and a diameter of
about 3t in. Through a fixed stop of ft in. diameter, the working aperture of the
lens was reduced to F. 17, which made it extremely slow.
This camera remained the standard type for several decades, especially for studio
work, until it was finally superseded by the much lighter and more compact bellows
camera. As the camera was not patented, the design was copied by practically every