Check out Eugen Guttmanns chapter (number 8) in this book: http://www.bromoil.info/PDF%20BOOKS/..._contents.html and see where that gets you.
Check out Eugen Guttmanns chapter (number 8) in this book: http://www.bromoil.info/PDF%20BOOKS/..._contents.html and see where that gets you.
Prints reveals truths that negative scans obscures.