> > > > "J. C. O'Connell" wrote: > > > > I dont agree with the final conclusion in this post. > > resolution is detemined by 1 black line next to > > one white line and determining a reference of how thin they > > can be made before the black and white fade into a middle grey > > value, MTF to be more specific... > > JCO > > I think the only objection that could be raised here is, I maintain the > white you see is a space, not a "line." > The white space merely represents how far apart the black lines are, > without which one would never be able to tell. You need something that > gives good contrast. White is logical, gray is okay too, if the contrast > is high enough. > The trick is, getting the line's weight or width to be the same size as > the separation _between_ the lines, so as to make spaces and lines of > equal width as they both get smaller.. > But, that's not a problem, just a condition of the testing procedure. > > Finally, it seems we're all in agreement in principle, except for the > nomenclature used, aren't we? > I call the white stuff a space, you call it a line, but we both have 100 > black lines per millimeter, or whatever value obtains. Not so?
Sort of, except for the fact that if you can resolve 100 black lines per mm on a white background you'll only manage a lesser number against a grey background. A specification that only mentions one component, and makes no mention of the contrast ratio between the two components, is flawed. That's what you are doing if you only describe the spacing between the black lines. If you are talking about the contrast ratio you need two pieces; the black part we all agree on, and the interleaved part. In other words there are a pair of lines - one black, one white. And the colour of each is equally important.
