The document discusses the early history and development of photography. It describes how (1) the camera obscura allowed images to be projected and captured, and the discovery that some chemicals like silver salts were light-sensitive, allowing images to be fixed physically. (2) In 1826, Joseph Niépce conducted the first permanent photograph by coating a pewter plate with bitumen and creating a direct positive after 8 hours of exposure. (3) In 1835, Louis Daguerre improved on this process using copper plates coated with silver iodide, which could produce clearer images in only 15-30 minutes when developed with mercury vapors.

1. The birth of photography
After the adoption of the “camera obscura” as a method to capture
images, the second fundamental discovery that allowed the birth of
photography was to verify that certain chemicals were sensitive to
sunlight. Photosensitive compounds such as silver compounds: silver
bromide and nitrate were discovered. This would allow to fix on a physical
support and in a timeless way the images captured in the “camera
obscura”

2. “Punto de vista desde las ventanas de Gras” Joseph Niépce. 1826
In 1826, the frenchman inventor Joseph Niépce, looking for a way to fix the
images of the exterior projected by the dark chamber, experimented with a plate of
pewter (zinc alloy, lead and tin) coated with a layer of bitumen of Judea.
The first photograph in history

3. “Punto de vista desde las ventanas de Gras” Joseph Niépce. 1826
After an 8-hour exposure inside the “camera obscura” the action of light had
altered the chemical composition based on bitumen of Judea by clarifying
and adhering to the pewter plane in the parts where it had been most
strongly affected. Removed from the plate the bitumen that had not adhered
to the pewter using lavender essence.
The natural dark
color of the pewter
plate provided the
shadows and judea
bitumen solarized
the lights. Niepce
had obtained a
direct positive
image that is
considered to be the
first photograph in
history.

4. Louis-Jacques Mandé Daguerre, a French painter twenty years younger
than Niépce, perfected his invention publishing in 1835 the results of his
research.
The process consisted of an image obtained inside the “camera obscura“ with
a time of exposure to light between 15 and 30 minutes. Daguerre used copper
plates coated with a layer of silver nitrate sensitive to light. To develop the
silver nitrate that had been affected by light he used mercury vapors, which
have the quality of turning this areas white. Finally, to fix the images so the
particles would remain unaffected by light we would use a bath of sodium
chloride.
The invention was used mainly to make portraits, it had a fast diffusion
throughout the world with the name of daguerreotype. Obtaining a one-only
positive image without using previous negatives.
Daguerretype

5. Louis-Jacques Mandé Daguerre, a French painter twenty years younger
than Niépce, perfected his invention publishing in 1835 the results of his
research.

6. The process consisted of an image obtained inside the “camera
obscura“ with a time of exposure to light between 15 and 30 minutes.
Daguerre used copper plates coated with a layer of silver nitrate sensitive
to light.

7. This method implied that the photographed object remained completely
stationary for a long period of time. This required the use of head and
back supports.

8. Daguerre used copper plates coated with a layer of silver nitrate sensitive to light.
To develop the silver nitrate that had been affected by light he used mercury vapors,
which have the quality of turning this areas white. Finally, to fix the images so the
particles would remain unaffected by light we would use a bath of sodium chloride.

9. Daguerrotipo del propio Louis Daguerre
The invention was used
mainly to make portraits, it
had a fast diffusion
throughout the world with the
name of Daguerreotype.
Obtaining a one-only
positive image without
using previous negatives.

10. Retrato por daguerrotipo del poeta Edgar Allan Poe