  Broad-band images in the Ca II H line, from the BFI instrument on the Hinode
spacecraft, show emission from spicules emerging from and visible right down to
the observed limb. Surprisingly, little absorption of spicule light is seen
along their lengths. We present formal solutions to the transfer equation for
given (ad-hoc) source functions, including a stratified chromosphere from which
spicules emanate. The model parameters are broadly compatible with earlier
studies of spicules. The visibility of Ca II spicules down to the limb in
Hinode data seems to require that spicule emission be Doppler shifted relative
to the stratified atmosphere, either by supersonic turbulent or organized
spicular motion. The non-spicule component of the chromosphere is almost
invisible in the broad band BFI data, but we predict that it will be clearly
visible in high spectral resolution data. Broad band Ca II H limb images give
the false impression that the chromosphere is dominated by spicules. Our
analysis serves as a reminder that the absence of a signature can be as
significant as its presence.
