Quote:
Originally posted by unregistered
you have outdone yourself Ben
please describe the specific procedure by which YOU could quantify anything at all by such methods
what 'tools' ?
how to 'set up' ?
how to 'calibrate' ?
how to measure ?
how to calculate the 'non-flatness' ?
a suggestion for the future Ben:
every time you get set to propose something,
ask yourself for the answer
you would have fewer posts, for sure
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Fair enough, I'll add details to this (ludicrous?) suggestion.
Needed: quad lined paper.
Rest the block at an angle, on top of the quad paper: the quad paper should be resting on top of the granite slab (available?), or a pane of glass.
The block's surface should reflect the grid.
Take a picture of the block's reflection. Have the film processed, and scan the picture (BMP preferable).
Open up an editor (heck, MS Paint would do!), and redraw the line over the reflection, in another color (i.e. red).
Look at the fringe on both sides of the line, to identify deviations.
Of course the quad paper is usually a 4 or 5 square per inch, so you'll have to repeat the procedure in diagonal increments of that reflection.
Error sources: The quad paper should be fairly straight. There may be an error from the camera's lens, as it may distort the picture, so I'd avoid using a macro feature. There may be additional error/distortion from the photo processing lab equip, similar to above (but should be minimal). There may also be an error from the scanner.
There will be a loss of resolution at many steps: transfer from film to paper/print, and from the print to the scan.
It would be a long process, and now that I type it out, I can see how innacurate it would be: at best, it might point out deflections that should be visually observable, but the quad paper idea would still be an excellent source to point this out.
Alternatively, there is metric quad paper out there, with a 1mm grid. It was easy to find, in Canada...