SetDirectory["C:\\drorbn\\AcademicPensieve\\Projects\\BBS"];
srcdir="C:\\drorbn\\BBS\\shots\\"

fnames=FileNames["17-1750-*", srcdir][[-3;;-1]]

BBImprove[shot_] := Module[{diag, s1,s2},
diag=Norm[ImageDimensions[shot]];
s1=ColorConvert[shot, "Grayscale"];
s2=ImageAdjust[ ImageApply[Max[#1-#2,0]&, {s1, Blur[s1, 0.01diag]}] ] // ColorNegate;
ImageAdjust[s2, 0.05]
];

origs=Import /@ fnames;
imps=BBImprove /@ origs;

ImageAssemble[Transpose[{origs, imps}]] // Rasterize

HomologyBBS=ImageAssemble[List /@ imps]

Export["HomologyBBS.png", HomologyBBS]