Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectroscopies and electron microscopies unravel the origin of the first
  colour photographs   The first colours photographs were created by a process introduced by Edmond
Becquerel in 1848. The nature of these photochromatic images colours motivated
a debate between scientists during the 19th century, which is still not
settled. We present the results of chemical analysis (EDX, HAXPES and EXAFS)
and morphology studies (SEM, STEM) aiming at explaining the optical properties
of the photochromatic images (UV-visible spectroscopy and low loss EELS). We
rule out the two hypotheses (pigment and interferences) that have prevailed
since 1848, respectively based on variations in the oxidation degree of the
compound forming the sensitized layer and periodically spaced photolytic silver
planes. A study of the silver nanoparticles dispersions contained in the
coloured layers showed specific localizations and size distributions of the
nanoparticles for each colour. These results allow us to formulate a plasmonic
hypothesis on the origin of the photochromatic images colours.

33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th