Spectral energy distributions of Mkn 841 in August 2008 (red symbols: INTEGRAL IBIS/ISGRI, 9–11 August; Swift XRT spectrum, 8 August; Swift UVOT, 13–15 August; NOT photometry, 13 August), on 3 February 2007 (green symbols: Swift XRT and UVOT) and at prior epochs, not from simultaneous data (taken from the NED Extragalactic Database, grey squares). The optical/UV data have been corrected for dust extinction in our Galaxy using E_B − V = 0.03 (Schlegel et al. 1998) and the extinction curve of Cardelli et al. (1989). The optical magnitudes from NOT and the optical-UV magnitudes from UVOT have been converted to fluxes according to Fukugita et al. (1995) and to Poole et al. (2008), respectively. In addition, the Swift BAT spectrum from the first 39 months of the mission is shown in blue (December 2004–February 2008, Cusumano et al. 2010). The errors include the statistical and systematic uncertainties. The model fitted by Bianchi et al. (2001) to the 1999 BeppoSAX spectrum, including a soft X-ray excess, a Comptonized spectrum of a hot corona with a high energy cutoff and a reflected component, is shown as a dashed curve.