Bar line shading in PNGs

[Phil Holmes]

Don't think this is a problem, but it is a bit interesting.  I've been 
trying to run my pixel comparator to compare 15.7 to 15.5 and getting a 
difference in the bar lines of every image - presumably owing to the work to 
stop the PDF artefacts.  Looking carefully at the bar lines, you can see 
they're not actually black - they're various shades of grey, in both 
versions.  The difference is that the shading has changed.  I attach 2 
highly magnified images - one with normal contrast, and one with it adjusted 
to emphasise the shading.

--
Phil Holmes
Bug Squad

accidentalenh.jpg
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accidental.jpg
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