Look like some minor problems with striations on the group photo, add a bit more alcohol to your collodion and these will go away.
nice shots, good poses. always have the fat guys in the back on group shots, and like the single soldier....tell him to "pull up your traps" and get the belt midway between the bottom two buttons on the sack coat. Ray
It would seem I was waiting a bit too long before dropping the plates in the bath, hence the striations. However, they are not visable on the actual plate and only seem to appear like that in the scanned image.