Context : The solar magnetic field is responsible for all aspects of solar activity .
Thus , emergence of magnetic flux at the surface is the first manifestation of the ensuing solar activity .

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 : The small active region NOAA 12118 emerged on 2014 July 17 and was observed one day later 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-Pérot Interferometer ( GFPI ) were complemented by synoptic line-of-sight magnetograms and continuum images obtained with the Helioseismic and Magnetic Imager ( HMI ) onboard the Solar Dynamics Observatory ( SDO ) .
Horizontal proper motions and horizontal plasma velocities were computed with local correlation tracking ( LCT ) and the differential affine velocity estimator ( DAVE ) , respectively .
Morphological image processing was employed to measure the photometric and magnetic area , magnetic flux , and the separation profile of the emerging flux region 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 provides a comprehensive view of growth and decay .
It 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 ^ { -1 } 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 dark pores .
We detected many elongated rapidly expanding granules between the two major polarities , with dimensions twice as large as the normal granules .

Conclusions :