 From the mid @-@ 1870s Busch 's illustrations were printed using zincography . With this technique there was no longer any danger that a wood engraver could change the character of his drawings . The originals were photographed and transferred onto a photosensitive zinc plate . This process allowed for the application of a clear , free pen @-@ drawn ink line , and was a much faster printing method . Busch 's use of zincography began with Mr. and Mrs. Knopp . 
 From the mid @-@ 1870s Busch <a href='null_genetive' title='1'><mark>'s</mark></a>illustrations <a href='uninflect' title='2'><mark>were</mark></a> printed using zincography . With this technique <a href='dey_it' title='3'><mark>there</mark></a> was no longer any danger that a wood engraver could change the character of his drawings . The originals <a href='uninflect' title='4'><mark>were</mark></a> photographed and transferred onto a photosensitive zinc plate . This process allowed for the application of a clear , free pen @-@ drawn ink line , and was a much faster printing method . Busch <a href='null_genetive' title='5'><mark>'s</mark></a>use of zincography began with Mr. and Mrs. Knopp . 
From the mid @-@ 1870s Busch  illustrations was printed using zincography . witt this technique it was no longer any danger that a wood engraver could change da character of his drawings . Tdaoriginals was photographed and transferred onto a photosensitive zinc plate . This process allowed fir the application of a clear , free pen @-@ drawn ink line , and was a much faster printing method . Busch  use of zincography began with Mr. and Mrs. Knopp .