I do wager that the maker of this dag was not quite a seasoned professional at the art of vignetting. Likely taking a try at the popular Boston style vignettes done by Southworth and Hawes, and Whipple, the lighting is in the style, but the effects don’t quite get that uniform cloud cover that he was certainly trying for. The daguerreotype’s qualities over-all are a strong technically, so he was likely taught by someone proficient in lighting for portraiture. But, the vignette is a step above just capturing once essence on a silver plate. It is a special effect that must be perfected independently on top of creating a perfect plate and image. I am not sure exactly how to get the effect working properly. That would be a question for Mike Robinson, whom is an expert daguerreian working today in Toronto. So if you desire to know the intricacies of creating this effect, send him an email, for he surely knows. Back to the dag at hand; a great sixth plate in fine condition, contained in a full case.