  Aims. Combining high-resolution and synoptic observations aims to provide a
comprehensive description of flux emergence at photospheric level and of the
growth process that eventually leads to a mature active region. Methods. Small
active region NOAA 12118 was observed on 2014 July 18 with the 1.5-meter GREGOR
solar telescope on 2014 July 18. High-resolution time-series of blue continuum
and G-band images acquired in the blue imaging channel (BIC) of the GREGOR
Fabry-P\'erot Interferometer (GFPI) were complemented by LOS magnetograms and
continuum images obtained with the HMI onboard the SDO. Horizontal proper
motions and horizontal plasma velocities were computed with local correlation
tracking (LCT) and the differential affine velocity estimator, respectively.
Morphological image processing was employed to measure the photometric/magnetic
area, magnetic flux, and the separation profile of the EFR during its
evolution. Results. The computed growth rates for photometric area, magnetic
area, and magnetic flux are about twice as high as the respective decay rates.
The space-time diagram using HMI magnetograms of five days traces a leaf-like
structure, which is determined by the initial separation of the two polarities,
a rapid expansion phase, a time when the spread stalls, and a period when the
region slowly shrinks again. The separation rate of 0.26 km\s is highest in the
initial stage, and it decreases when the separation comes to a halt. Horizontal
plasma velocities computed at four evolutionary stages indicate a changing
pattern of inflows. In LCT maps we find persistent flow patterns such as
outward motions in the outer part of the two major pores, a diverging feature
near the trailing pore marking the site of upwelling plasma and flux emergence,
and low velocities in the interior of pores. We detected many elongated rapidly
expanding granules between the two major polarities.
