The movie above shows an observations of a sunspot formation during July 2009 observed simultaneously with spectropolarimeter and Fabry-Perot instruments as well as two speckle cameras at the VTT. The pore starts to accumulate more magnetic flux and eventually the penumbral filaments form. In the movie, you see the G-band images which shows the photospheric structures.
We have several publications based on this data:
Schlichenmaier, Rezaei, Bellot-Gonzalez, Waldmann, A&A 512, L1 (2010)
Schlichenmaier, Bellot-Gonzalez, Rezaei, Waldmann, AN 331, 563 (2010)
Schlichenmaier, Bellot-Gonzalez, Rezaei, IAUS 273, 134 (2011)
Schlichenmaier, Rezaei, Bellot-Gonzalez, ASPC 455, 61 (2012)
Bellot-Gonzalez, Bellot Rubio, Ortiz et al., ASPC 463, 251 (2012)
Rezaei, Bellot-Gonzalez, Schlichenmaier, A&A 537, A19 (2012)
Jurcak, Schlichenmaier, Rezaei, Bellot-Gonzalez, PASJ 663, 3, L1 (2014)
Jurcak, Bellot-Gonzalez, Schlichenmaier, Rezaei, A&A 580, L1 (2015)
Bellot-Gonzalez, Jurcak, Schlichenmaier, Rezaei, SOLARNET IV (2017)
Jurcak, Rezaei, Bellot-Gonzalez, Schlichenmaier, Vomel, A&A 611, L4 (2018)