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- Jan 22, 2011
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According to "Handbook of Dimensional Meaurement", 30 millionths, with blue light.
https://books.google.com/books?id=qFiUBgAAQBAJ&pg=PA279&lpg=PA279&dq=straightedge+light+gap&source=bl&ots=WRcrfRuw0p&sig=AnDYuQje1_qlsUqd8deUKtb8hsY&hl=en&sa=X&ved=0ahUKEwjsu9Xy97DJAhWJNiYKHUiJB8IQ6AEIJzAC#v=onepage&q=straightedge light gap&f=false
I would have to suppose as far as reliability and trust, it would depend the individual and several other variables. I believe they author is referring to ideal conditions. Defraction of white light would cause you to see a shift from red @ 70 millionths down to the blue at 30. I would assume this would require a full visible spectrum light source.
https://books.google.com/books?id=qFiUBgAAQBAJ&pg=PA279&lpg=PA279&dq=straightedge+light+gap&source=bl&ots=WRcrfRuw0p&sig=AnDYuQje1_qlsUqd8deUKtb8hsY&hl=en&sa=X&ved=0ahUKEwjsu9Xy97DJAhWJNiYKHUiJB8IQ6AEIJzAC#v=onepage&q=straightedge light gap&f=false
I would have to suppose as far as reliability and trust, it would depend the individual and several other variables. I believe they author is referring to ideal conditions. Defraction of white light would cause you to see a shift from red @ 70 millionths down to the blue at 30. I would assume this would require a full visible spectrum light source.