The optical continuum radiation will also be affected by extinction and
reddening. Suppose the intrinsic spectrum of the (optical) continuum
has a form 
. Furthermore, suppose
that the observed (i.e. reddened) optical continuum spectrum is
. The difference between
and 
is related to the reddening towards the
source. From the definition of reddening, it is easily seen that
where 
and 
are the frequencies characterizing the
B-band and V-band respectively.
Unreddened Seyfert 1 nuclei in the luminosity range occupied by
MCG-6-30-15 tend to have optical continua with 
(e.g. see
study of Morris & Ward 1988, and note that a flat flux spectrum in
wavelength space implies 
when considered in frequency space).
Fitting the (galaxy-subtracted) blue spectrum of the nucleus of
MCG-6-30-15, we conclude that lies in the range
4.5-5. Assuming that the intrinsic optical spectrum of MCG-6-30-15 is
similar to that found in unreddened Seyfert 1 nuclei, the reddening of the
optical continuum source E(B-V) is in the range 0.65-0.78.
The reddening of the optical continuum source is consistent with the lower
end of the reddening derived from the H /H 
Balmer ratio.
Assuming that the optical continuum is associated with an accretion disk
embedded inside the BLR, this result suggests that little dust is present
between the accretion disk and the region where the bulk of the the broad
line photons are emitted.