Dr. Jean-Louis MARIGNIER
Jean-Louis Marignier

Researcher at the CNRS (National Center for Scientific Research)
Head of the picosecond electron accelerator facility ELYSE at University of Paris Sud 11 Orsay.

Laboratoire de Chimie Physique , UMR 8000 CNRS/Université Paris-Sud 11,
Bâtiment 349, Université Paris-Sud 11 , 91405 Orsay Cedex, France
Tel: +33 1 69 15 75 69
Fax: +33 1 69 15 61 88
Email : jean-louis.marignier@u-psud.fr


Fields of research          Diplomas            Teaching Activities            Awards            Publications



Publications in Radiation Chemistry field

Publications in History of Photography field

Organization of training courses in History of Photography

Exhibitions in History of Photography

Audio-Visual Achievements

Re-discovery of the Heliography process

Helioengraving process

The world's first photograph

The tin plates shown by Niepce in England

Re-discovery of the Physautotype process

Reconstitution of the "Table Servie"

Virtual reconstitutions on computer

Fields of Research

Radiation chemistry studied by pulse radiolysis at picosecond time range. Fast optical absorption detection with streak-camera. Chemical processes in silver photography. Synthesis of metal nanoaggregates.

History of Photography : Study of the invention of Photography by Nicéphore Niépce. First reconstruction of the process invented by Niépce and named by him "Heliography". Discovery of a unknown photographic process, the "Physautotype", invented by Niepce and Daguerre in 1832.
Main results obtained on the reconstruction of the processes of Niépce           (http://niepce.com)


1977-1979 : Ph.D. at the Laboratory for Radiation Chemistry : “Study of radiolytic process of sulfured molecules in liquid state by pulse radiolysis".

1981-1987 : Thesis of "Doctorat d’Etat" (Doctor of State) at the Laboratoire de Physico-Chimie des Rayonnements (LPCR) “Synthesis of metal nanoaggregates induced by ionizing radiations, structure and thermodynamical properties".

Teaching activities

1995 - 2002 : Professor at University of Orsay in Molecular Physical Chemistry (speciality : Effect of ionizing radiations in liquid phase)

Since 1995 : Professor at INP (Institut National du Patrimoine). Paris in the Department of Photography

September 2000 : Visiting professor in residence at George Eastman House
(Rochester ) in the Advancy residency program in
photographic conservation (Mellon Project)


• "de Salverte" Medal (1991) awarded every two years by the SOCIETE FRANÇAISE DE PHOTOGRAPHIE (French Society of Photography) for an important work in the knowledge of photographic processes.

• Grand Prize KODAK-PATHE-LANDUCCI (1991) awarded by the ACADEMY OF SCIENCES in Paris.


Publications in radiation chemistry field

Publications in History of photography field           Main results obtained on the reconstruction of the processes of Niépce  


Chapters in books :

• Ultra-fast pulse radiolysis methods, J. Belloni, R.A. Crowell, Y. Katsumura, M.Z. Lin, J.-L. Marignier, M. Mostafavi, Y. Muroya, A. Saeki, S. Tagawa, Y. Yoshida, V. De Waele and J.F. Wishart, in 'Recent Trends in Radiation Chemistry', J.F. Wishart, B.S.M. Rao (Eds), World Scientific, 2010, pp. 121-160.

Articles :

• Radiation-induced synthesis of a-Al2O3 supported nickel clusters: Characterization and catalytic properties,
N. Keghouche, S. Chettibia, F. Latreche, M.M. Bettahar, J. Belloni, J.L. Marignier, Radiation Physics and Chemistry 74(2005) 185–200

• ELYSE - A picosecond electron accelerator for pulse radiolysis research.
J. Belloni, H. Monard, F. Gobert, J-P. Larbre, A. Demarque, V. De Waele, I. Lampre, J-L. Marignier, M. Mostafavi, J.C. Bourdon, M.Bernard, H. Borie, T.
Garvey, B. Jacquemard, B. Leblond, P. Leperrcq, M. Omeich, M. Roch, J. Rodier, R. Roux,
Nucl. Inst. Meth. Phys. Res. A, 539 (2005) 527-539.

• Time-resolved spectroscopy at the picosecond laser-triggered electron accelerator ELYSE.
J. L. Marignier, V. de Waele, H. Monard, F. Gobert, J. P. Larbre, A. Demarque, M. Mostafavi, J. Belloni, Rad. Phys. Chem. 2006, 75,1024

• Hydrated electron decay measurements with picosecond pulse radiolysis at elevated temperatures up to 350 °C.
G. Baldacchino, V. De Waele, H. Monard, S. Sorgues, F. Gobert, J.P. Larbre, G. Vigneron, J.L. Marignier, S. Pommeret , M. Mostafavi Chem. Phys. Lett. 2006, 424 (1-3), 77-81

• Geminate recombination measurements of solvated electron in THF using laser-synchronized picosecond electron pulse.
V. De Waele, S. Sorgues, P. Pernot, J-L. Marignier, H. Monard, J-P. Larbre, M. Mostafavi,
Chemical Physics Letters, 2006, 423 (1-3).30-34

• Absolute calibration for a broad range single shot electron spectrometer.
Y. Glinec, J.Faure, A. Guemnie-Tafo, V. Malka, H. Monard, J.P. Larbre, V. De Waele, J.L. Marignier and M. Mostafavi,
Review of Scientific Instruments. 2006, 77, 1-6

• Ring opening of the cyclobutane in a thymine Dimer Radical Anion.
C. Chatgilialoglu, M. Guerra, P. Kaloudis, C. Houée-Levin, J.-L. Marignier, V. N. Swaminathan and Th. Carell.
Chem. Eur. J. 2007 13 8979-8994

• Irradiated-induced Ag nanocluster nucleation in silicate glasses : Analogy with photography.
R. Espiau de Lamaestre, H. Béa, H. Bernas, J. Belloni and J.L. Marignier. Phys. Rev. B 2007 76 205431-205449

• Kinetics study of the solvated electron decay in THF using laser-synchronised picosecond electron pulse.
V De Waele et al.
Nuclear Science and Techniques 2007 18 1 10-15

• Development kinetics of silver clusters on silver halides.
S. Grzesiak, J. Belloni, J.-L. Marignier.
Radiation Physics and Chemistry 77 (2008) 713–727

• Radiolytic formation of tribromine ion Br3- in aqueous solutions, a system for steady state dosimetry.
M Mirdamadi-Esfahani, I. lampre, J.L. Marignier, V. De Waele and M. Mostafavi
Radiat. Phys. Chem. 78 (2009) 106–111



Héliographies. 1989, première reconstitution du procédé de Nicéphore Niépce.
Catalogue de l’exposition du Musée Niépce. Ville de Chalon-sur-Saône. (12 pages)

Niépce, l'invention de la photographie, 602 p., (Editions Belin, Paris, 1999)

Niépce. Correspondance et papiers, avec Manuel Bonnet, 1532p. , (Maison Niépce, Saint-Loup-de-Varennes, 2003)


Nicéphore Niépce
in “Encyclopédie du XXe siècle” Editions Hachette Encyclopédie (1994)

Historique des procédés photographiques
in “Encyclopédie du XXe siècle” Editions Hachette Encyclopédie (1994)

W.H.F. Talbot
in “Encyclopédie du XXe siècle” Editions Hachette Encyclopédie (1994)

La Photographie
L’Actualité Chimique , special issue devoted to Photochemistry Act. Chim. 7(supp), 85 (1994).

Asphalt as the world’s first photopolymer
in “Processes in Photoreactive Polymers”
V.V. KRONGAUZ and A.D. TRIFUNAC, Editors ,
CHAPMAN & HALL, New-York (1995) p.3 à 33.

La photographie imprimée
In « La photographie et le livre » Ouvrage collectif
Editions “Trans photographic press“ (Paris Avril 2003)

L'Héliographie (in general, photographic process, photoetching process), le Physautotype, la Similigravure, l'Offset, la Paniconographie
Seven chapters in "Le Vocabulaire Technique de la Photographie". Anne Cartier-Bresson Ed. (Editions Marval - Paris 2008))


Historical light on Photography
Nature,346, 115, (1990)

A la découverte des héliographies de Niépce
Le Photographe, 1470, 13, (1989)

Heliographische Verfahren des Joseph Nicéphore Niépce in der praktichen anwendung.
Photo-Antiquaria., 2, 5, (1989)

Pratiques des procédés héliographiques
Interphotothèque, 43, 34, (1990)

Mystères éclaircis sur la plus ancienne photo au monde
Le Photographe, 1480, 50, (1990)

Reconstitution des procédés héliographiques de Nicéphore Niépce ultérieurs à 1824.
Compte rendu du congrès de l’Association pour la Recherche Scientifique sur les Arts Graphiques (ARSAG) Paris -sept 1991 p. 43 à 54

Gewust wie, Gewust womit, gewust wie lange
Photo-Antiquaria, 2, (1991)

Reconstitution du premier procédé photographique mis au point par Joseph Nicéphore Niépce vers 1829
J. Chim. Phys., 88, 865, (1991)

L’invention de la photographie
Bull.Soc.Vaud.Sc.Nat., 81, 199, (1992)

Les Bras morts de la technologie, l’héliographie
Dossier de l’Audiovisuel (INA Ed.), 45, 13, (1992)

Première reconstitution du deuxième procédé photographique au monde
Le Photographe, 1499, 26, (1992)

Films photosensibles à partir d’émulsion de bitume
Comptes-Rendus du 1er Congrès Mondial de l’Emulsion. Edition EDS Paris (1993)

Découverte de l’invention par Niépce et Daguerre d’un procédé photographique à base de colophane
Le Photographe, 1524, 36-42, (1995)

The Invention of Photography by Niépce. From early successes in 1824 to the improved process in 1829 and the collaboration with Daguerre.
Proceedings of the 48th annual meeting of IS&T (Society for imaging Science and Technology) 1995

Photography : The Invention of N. Niépce.
New England Journal of Photographic History, 144, 37-46, (1995)

Heliography : the Photographic Process Invented by N. Niépce before the association with Daguerre
Daguerreian Annuals 1996

Photochemistry of asphalt for the production of images
J. Imag. Sci. Tech., 40, 123-133, (1996)

L’invention de la photographie
C. R. Acad. Sci. Paris (Série II b), 325, 415-420, (1997)

The Physautotype, The world's second photographic process re-discovered
Daguerreian Annuals 2003, p. 350.

La Table Servie de Niépce. Enquête sur l'une des premières photographie de l'histoire
Le Photographe, 1622, 32, (2004)

Les mystères de la chambre noire
l'Alpe, 39, 16, (2008)

Le laboratoire photographique de Fortuné Joseph Petiot-groffier
Le Photographe, 1663, 88, (2008)

Aux origines de la photographie : Nicéphore Niépce
Lettre de l'Académie des Beaux-Arts, 53, 26, (2008)

Aux origines de la photographie : Nicéphore Niépce
Account of the conference given on June 25th 2008 at the invitation of the Academy of Fine Arts (Institut de France)
to inaugurate the new section "Photography" created in 2008 : First conference given since the historical one of Arago
on August 19th 1839 for the divulgation of the invention of photography
Comptes-Rendus des Communications de l'Academie des Beaux-Arts- Institut de France, pages 53 to 84, 2009 (published in 2010)


Introductory course to Heliography process
Organized at the Niépce Museum of Chalon-sur-Saône from the 1 to September 3, 1991 (12 trainees)

Idem, from 31 August to 2 september 1992 (10 trainees)

Introductory course to Heliography process
Organized at the Fine Arts School of Geneva (Department of Visual Arts)
GENEVA from 10 to 14 may 1993 (12 trainees)

Introductory course to Physautotypie
Organized at the Fine Arts School of Geneva (Department of Visual Arts)
GENEVA from 16 to 20 may 1994 (10 trainees)

Introductory course to the very first photographic processes
Organized at the Fine Arts School of Geneva (Department of Visual Arts)
GENEVA from 1 to 5 february 1999 (12 trainees)

Reconstitution of the heliographic process invented by J.N. Niépcetowards 1824
in the National Exhibition organized for the 150th anniversary of the birth of the photography : “La Photographie Révélée”
Archives Nationales, Paris, 17 october-17 december 1989

The invention of photography by N Niépce and practice of heliographic processes
Celebrations of the Fiftieth anniversary of the CNRS
Palais de la Découverte. Paris. 10 to 17 November, 1990

Héliographies; 1989, first reconstitution of the process of Nicéphore Niépce.
Musée Niépce de Chalon-sur-Saône. 15 december to 15 march. 1989
Part of this exhibition have been exhibited for several years in this Museum.s

Reconstitution of the first photographic process invented by N Niépce
FAUST 90. Forum sur l’Art et l’Univers Scientifique et Technique.
Toulouse 23 - 28 november 1990

L’héliographie, the world's first photographic process
in the exhibition “Appareil photo, objet familier”
Cité des Sciences et de l’Industrie de la Villette. March to June 1992

The world's first photographic process
in the exhibition “Images et Sciences” organized by the CNRS and the FEMIS
Palais de la découverte , October - November 1992.

The invention of Photography
Ministry for the Economy - Ministry for the Budget, PARIS June 15 to July 15, 1993

The invention of photography
in the exhibition La Chimie et l’Art organized by Artchim Midi-Pyrénées and presented in PORTUGAL :
- University of AVEIRO 1st to 30 april 1994
- PORTO may-june 1994
- Science Museum of LISBOA from July to November 1994

The invention of photography
Noisy le Roi (FRANCE)
20 november to 6 décember 1996

The invention of photography,
CHALON-SUR-SAONE, 15 and 16 january 1998.

The invention of photography,
Demonstrations of the techniques invented by Niépce
Week of the Science
ORSAY, 20 october 1999.

The invention of photography,
Demonstrations of the techniques invented by Niépce
Fête de la Science
ORSAY, october 2001.

Re-creation of the whole researches of Niepce toward the invention of photography,
Permanent exhibition since 2002 in the Museum of the House of Niepce
(improved every years with additional elements coming from the new results)

"La photographie révélée"
J.L. Marignier (LPCR-SCAVO-Orsay)
video film of 12 minutes : animation on the photographic development

"Magie de l'image"
G. Roussi, S. Guyon et J.L.Marignier (Scavo-Orsay)
26 minutes video film. Main broadcasts of this film on TV channels:
• Télessonne (cable television)
• Antenne 2: 2 minutes on the process Heliography at 1 p.m. at the Television news of Saturday Nov. 25, 1989.
• FR3: The reconstitution of process Heliography in "Tranches de Sciences" on November 6, 1990..
• Channel 11 of the television of Thailand in an emission for which I also gave an interview at the time of a congress in Bangkok where I were invited.
• FR3: The reconstitution of process engraving in the emission "Ce n'est pas sorcier" Sunday December 17, 1995 and on June 24,1996.

"Niépce révélé"
J.L. Marignier et Ch. Prédignac
Film of 9 min in the scientific emission "Archimedes" on ARTE channel (February 1997)

Demonstrations of the techniques invented by Niépce
J.L. Marignier Television news at 8 p.m., France 2 channel (duration 1 mn 40) Sunday October 24, 1999.

Demonstrations of the techniques invented by Niépce
J.L. Marignier Television news at 7 p.m., France 3 channel - Ile de France. (duration 4 mn)Wednesday october 2, 1999

"Les mystères de la chambre noire"
P. Goetals, M. Bonnet et J.L. Marignier
26 minutes video film on the invention of photography by Niépce
presented on FR 3 Channel, saturday March 18, 2000

"Pêcheur d'histoire" on National Radio broadcast : France-Inter, devoted to
Nicéphore Niépce on July 17, 2000 (15 min of interview).

"Le Gras, restauration de la maison de Niépce"
J.L. Marignier, S. Guyon et P.Y. Mahé (Scavo-Orsay-Speos)
Film video de 10 minutes montrant pour la première fois les premières expériences de Niépce reconstituées dans son atelier laboratoire en cours de restauration.
- Presented at the International Festival of the Photography ARLES (July 2000)
- Admitted in the official selection of the International Festival of Scientific Film of ORSAY (April 2001)
- Admitted in the official selection of the International Festival of film of researcher of NANCY (May 2002)

First Web site devoted to Niépce (in French and English). Brought into service in April 2002

Texts and recording of the comments of the interactive audioguide
of the visit of the Museum of the CNAM (Conservatoire National des Arts et Métiers - Paris) for the part of this Museum devoted to the pioneers of photography


Main results obtained by J.L. Marignier                                           
      in the reconstruction of the photographic                              
      processes invented by Nicéphore Niépce (1765 - 1833)

Laboratoire de Chimie Physique UPS/CNRS Orsay - FRANCE     

      The World's first photograph at Austin TX - USA     The Images shown by Niepce in England              
       The Discovery of the Physautotype process              The reconstitution of the Table Servie

    Première            first photograph            Moonlight          Ruis of an abbey           Table servie
        Heliography           Physautotype            The world's first photograh              Ruins of an Abbey
            La Table Servie            Virtual Niepce's House

1989 to 1992


First images obtained in the camera obscura using the process invented by Niepce, since his death in 1833 

The images was obtained by the most sophisticated form of the invention of Niepce that he described in 1829, i.e. on silver plated copper plate with the process of inversion of the negative asphalt image by the action of iodine vapors.
After this first success, it was possible for the first time :
• to determine the photosensitivity of the system (few 10-6 ISO) and hence of the exposure time
              (3 days under the sunlight with an aperture of the lens of f/4).
• to demonstrate the absence of any whitening of the asphalt under the action of light.
• to determine the resolution of the image (102 pairs of lines per millimeter).
• to show that the process gives black and white images with a good gradation of hues.

Discovery of the possibility to produce on pewter (Sn), bitumenfirst heliograph images which can be seen as negative or positive depending on the orientation of the light. 
• taking into account one sentence written by Niepce in his "Notice sur l'Heliographie" : suggestion that Niepce could have obtained such kind of images (catalog of the exhibition at the Nicéphore Niépce Museum, published on 15 th december 1989)
• Images on glass and on lithographic stones (limestone) which exhibit the same phenomena
                                                                                                        Heliograph made in a camera obscura
using the process invented by Niépce
(J.L. Marignier 1989)

Reconstruction of the helioengraving process

           • Images etched with acid in copper or pewter (Sn) plates
           • Prints of these images on paper

=>These very first results have been presented at the Symposium for 150th anniversary of the birth of photography at Vevey (Switzerland) in july 1989
=>The images have been exhibited in October-November 1989 at the Archives Nationales in Paris and then at the Nicephore Niepce Museum in Chalon-sur-Saône from 15th december 1989 to 15 th march 1990. These heliographs are still in the archives of this museum.

Reconstruction of the helioengraving process with the techniques described by Niepce as : "peindre et graver tour à tour" (to paint and to etch alternatively)

Observation of the world's first photograph made by Niépce, at the Harry Ransom Humanities Research Center (HRHRC) at the University of Texas - AUSTIN USA (July 1990)

• First determination of the nature of this image :First photograph it is a negative/positive bitumen image made on pewter (Sn). The bitumen used by Niépce is still onto the pewter plate. This confirms the suggestion we proposed in 1989 and hence our good interpretation of the "Notice sur l'héliographie". Due to an underexposure of the image in the camera obscura the bitumen varnish is completely eliminated in the dark areas but also partially dissolved even in the most intense areas. It is known that in the engraved images on metal, this dissolution can lead to a discontinuous structure of the remaining varnish called "sablé", i.e. "sand effect", by A. Lemaître, the engraver who collaborated with Niépce (published in 1990 and 1999). In these conditions the exposure lasts 2 days under the sunlight.

The oldest world's photograph as reproduced
by Kodak in 1952

After this it has been possible to date the "View from the window at Gras" as made by Niépce during summer 1827 and not in 1826 as it was written before.

First photograph Gernsheim                      First photograph by Marignier
                     The image made by Niepce as it was in 1952                          Image made by J.L. Marignier

August 1993 : Investigations in the now closed asphalt mines where Niépce had purchased the bitumen.
          • Extraction of the bitumen from 15 kilograms of bituminous ore and production of heliographic images              with it.

April 1995 : Discovery at the Musée du Cinéma in Paris of an unknown varnished drawing on paper used by Niépce
Niepce in England Drawing• It represents the image which can be seen on the plate called "Ruins of an Abbey" now preserved at National Media Museum, Bradford, UK. This drawing covered with a varnish to make the paper translucent is absolutely identical to an engraving preserved at The George Eastman House on which one can read that it is a reproduction of an painting from Daguerre by the engraver G. Maile and that the true titled is "Un clair de Lune", i.e. "Moonlight". Details and dimensions of this drawing corresponds exactly to the image on the plate in UK and this leads to the conclusion that this varnished drawing was reproduced by Niepce by contact printing and not with a camera obscura (published in 1999, ed. Belin p. 494), which seems obvious because Niépce would not have varnished it.

Niepce in England GEH Rochester
This photograph shows the engraving preserved at the George Eastman House (Rochester NY USA). This is an engraving on which one can read "Dessiné par Daguerre" et "Gravé par G. Maile", dimensions and details are identical to the drawing in Paris and to the plate in England (see after for the comparison)

November 1997 at the Royal Photographic Society, Bath, UK. Observations of the three plates shown by Niepce in England in 1827
Ruins of an abbey Bradford - Niepce in England

• Observation of the image : "Ruins of an Abbey", which is the reproduction of the "Un Clair de Lune", gives rise to some questions about the plate and the process used. The aspect is the reverse of the one expected for an engraved image by Niepce's process. Dark areas are very naked polished metal while the area of intense light are matte. While the metal is a white bright one it is not sure that it is a pewter (Sn) plate. In 1999 (Ed. Belin), I suggested to perform analysis of the metal and of the different areas.

Ruins of an Abbey : the plate  preserved in England
    Ruins of an Abbey Bradford NMM Niepce in England                Niépce. L'invention de la photographie. Niepce in England
 In 1999, J.L. Marignier showed in his book, the connection between the engraving in Rochester, the plate in England, and the drawing on paper he discovered at the Musée du Cinéma in Paris

Comparison Bradford Paris - Niepce in England
Comparison between the drawing discovered at the Musée du Cinéma (Paris) and the plate in Bradford museum (on the drawing, look at the pinhole on the top left angle which is reproduced on the pewter plate)

Technical studies about the process

• Solvent extraction of the chemical components of the bitumen.                  
          • Study of the photosensitivity of the different components.
• Study of the effect of the concentration, the temperature during the dissolution, the stirring during the       dissolution, the temperature of drying, the ageing of the solution, the thickness of the bitumen film.
• Study of the effect of the reflectivity of the base.
• Determination of the spectral sensitivity of the bitumen film. 

1992 to 2004


Re-discovery of the unknown photographic process using the residue of the distillation of oil of lavender (feb 1992)

• Analysis of the letters between Niepce and Daguerre leads to the conclusion that this process was invented by Niépce and Daguerre together during summer 1832.
• Identification of this process as the one called "PHYSAUTOTYPE" by Niépce and Daguerre in their correspondence in 1832.
• In 1993, discovery that the same process can be implemented also with rosin and a lot of aromatic compounds.

Identification of the image called "La Table Servie" as a physautotype made by Niepce in 1832 - 1833

Table Servie Jardin Niépce
1995 : Discovery in the travel diary of James
David Forbes (Scotland) in 1839 that he was a witness of the image called " La table servie" which he saw in the hands of the son of Niépce, Isidore Niépce in Paris. This testimony leads to attribute without no doubt this image to Niepce. And a careful analysis led to conclude that this picture was taken using the physautotype process.
2003 : Discovery of another witness of the image of " La table servie", the russian academician Joseph Hamel.
• 2004 : reconstitution of the " Table servie" in Niépce's garden at Saint-Loup-de-Varennes by the physautotype process.
                                                                                                                   Reconstitution of Niepce's Table

   Table Servie 1902                Table servie Physautotype
Left : reproduction published in 1902 of  Niepce's plate (At present day, the plate is lost) . Right : Physautotype made by J.L. Marignier and M. Lourseau with a camera obscura of the reconstituted table of Niépce (August 2004)

Processes using powders
Discovery that under the influence of Daguerre, two processes have been derived from the heliographic process and from the physautotype process.

Two example of images obtained by contact printing on powders spread on metal. Left : powder of bitumen on silver. Right : powder of colophony on silver.
1995 to 2004


Reconstruction of the experiments performed by Niepce before the invention of the bitumen process

• Images made by Niépce in 1816,using the silver chloride precipitate, and called by him : retinas.
• Images made with iron chloride.
• Images made with guaiacuum resin.

1992 to 2004


Reconstruction with a computer of Niepce's estate as it was in 1830
• Identification of the window from where was taken the world's first photograph
• Determination of the position of the camera obcura.
• Determination of the focal distance of the lens used.
• Identification of the details of the image.
Calculations indicate that, since 1827, the window has been shifted toward the west by 70 cm.
=> Publication of these results in september 1999 (Ed. Belin).

• In december 1999, investigations around the window in Niépce's house confirm that it has been shifted since the time of Niepce and that the shift is exactly of 70 cm. (results presented in the movie "Restoration of Niépce's house" in 2000)
=> Results presented in the movie "Restoration of Niépce's house" Spéos-SCAVO-CNRS, 2000.

Virtual reconstruction of the "View from the window at Gras"

• Calculation with computer of the shadows of the landscape at every hours of the day for any day of the year.
• Reconstitution by computer of the world's first photograph, by calculating the accumulated intensity of the light produced during one day by the image projected inside the camera obscura on the plate.
• Determination of the period of the year (around the 15th of July) where this picture was made in 1827.
Results presented at the Symposium on the world's first photograph at
the Harry Ransom Humanities Researches Center - Austin - Texas in November 2003.