Louis-Jacques-Mande Daguerre

Boulevard du Temple, Paris, 1838, by Daguerre (the first picture of a person). The image shows a busy street, but because exposure time was more than ten minutes, the traffic was moving too much to appear. The exception is the man at the bottom left, who stood still getting his boots polished long enough to show.

2Ag+Halˉ → 2Ag + Hal2
Halˉ + hν → Hal• + eˉ
Ag+ + eˉ → Ag
Hal• + Hal• → Hal2
Principle of work of photography silver halide

Black-and-white photography
Negative photoprocess
Positive photoprocess

Hermann Wilhelm Vogel
(26.03.1834 – 17.12.1898)
H.W. Vogel was a German photochemist and photographer who made key contributions to practical color photography. From 1860 he was a professor at Berlin's Technische Hochschule (from 1879, the Technical University of Berlin), where he introduced photography as a field of study.
In 1873 he discovered how to extend the spectral sensitivity of photographic emulsions (which until then were then only sensitive to blue and UV light) to green light by adding dyes. By 1884 he had discovered how to extend the sensitivity into the orange. However the achievement of a fully panchromatic response, into the red, had to wait until fresh dye-discoveries, in the early 1900s, shortly after his death.
Die chemischen Wirkungen des Lichts und die Photographie (2. Aufl., Leipzig 1883)

The first synthetic organic dye –
Perkin's Mauveine (1856 )
The first cyanine dye –
Cyanine (Quinoline Blue)
was also synthesized in 1856

λmax = 453 nm; ε = 137000 (n-hexane)
λmax = 758 nm; ε = 305000 (CH2Cl2)
λmax = 417 nm; ε = 112000 (MeOH)
460 nm; ε = 33300 (MeOH)

AgHal sensitization
AgHal desensitization
Spectral sensitization of photoemulsion silver halide
(sensibilis(lat) – чутливий)

Förster-Dewar-Knott rule (FDK rule)

λmax = 558 nm
λmax = 495 nm
λmax = 586 nm
λmax = 411 nm
λmax = 596 nm
λmax = 558 nm

Electron-donor ability:
-strong-
-medium-
-weak-
Dependences of total charges distribution in end groups (ΣqN) and polymethine chain (ΣqC) on electron-donor ability of end groups (Het) and chain length (n)

Electronic absorption spectra of dyes 1-5 in CH2Cl2 and DMF

The portion of the EM spectrum from 400-800 is observable to humans- we (and some other mammals) have the adaptation of seeing color at the expense of greater detail
400
500
600
800
700

Additive method of colours synthesis

Subtractive colour model (ideal CMY-scheme)
B
R
G

James Clerk Maxwell (13.06.1831–05.11.1879)
J.C. Maxwell was a Scottish theoretical physicist and mathematician. His most important achievement was classical electromagnetic theory.
Maxwell contributed to the area of optics and colour vision, and is credited with the discovery that colour photographs could be formed using red, green, and blue filters (in 1861)
The first permanent colour image, taken by Maxwell in 1861 (a tartan ribbon)

Additive principle of colour photography

Subtractive method of colours synthesis

Subtractive method of colours synthesis

Curves of spectral sensitivity of colour negative photofilm to blue, green and red rays