lithographic spidering

I see it now and then. Looks like the top layer has shrunk leaving the gaps. I like the look. It would be fun to be able to replicate it.

Steve

In woodworking there are a few terms for it - alligatoring, crackling, among others.  It has to do with a combination of age and temperature.  As the varnish or coating layer hardens with age and the substrate (in this case the metal) expands and contracts with varying temperatures the finish cracks and withdraws showing the gaps between. 

I'm currently in the process of repairing and refinishing an older player piano, from the 1920s, that was finished with a shellac based finish.  The exterior finish all over it has alligatored.  Very lucky for me because shellac is an alcohol based finished and remains soluble in alcohol.  I could just soften and redistribute the finish but I'm actually removing it with denatured alcohol and elbow grease and then applying a new shellac finish. 

Lithographic varnishes are slightly different.  Most older or primitive printing varnishes were oil based.  Modern printing finishes are aqueous (water based).  In any case, because of their make up and application they are not repairable.  Restoration would involve removal and replacement.

I agree with Steve, however.  I think it adds to the overall look and charm of the items.  It certainly suggests its age.

LEAVE IT ALONE!  I cannot stress  that enough.  Originality is the key.  I also agree with Steve, it adds to the charm and originality of the piece.

Hmm, if the litho varnish is oil-based, maybe the same forces are at work as in craquelure?

https://en.wikipedia.org/wiki/Craquelure

nickaix posted:

Hmm, if the litho varnish is oil-based, maybe the same forces are at work as in craquelure?

https://en.wikipedia.org/wiki/Craquelure

Just another name for alligatoring.

Byrdie posted:

In woodworking there are a few terms for it - alligatoring, crackling, among others.  ...

thanks... that seems to make sense.  i finally did find some writings that talked about "crackling", but they were based on the assumption that you actually wanted that finish.  they suggested about the same thing that you describe as being the cause, though.

for those concerned, no worry, i don't touch/ restore anything lithographed aside from cleaning.  i have some more minor examples, but this one is definitely the loudest.  it's an interesting look to say the least.

cheers...gary