These are the same problems, although to a much greater extent, with the old kinescope
recorders that predated video tape.
I will continue to look for a glass/chrome USAF target and try to get a good contact
made on film. In the meantime, I believe a well honed straight edge
masked to a strip of film could produce a sharp high contrast edge (properly exposed).
When scanned at maximum optical resolution, a gradation of 3 to 4
pixels would be very good, I think.
Jim Sims
"Hemingway, David J" wrote:
> God I hate to allow the film recorder demons out of the bag but here goes.
> The actual resolving power of a HR6000 is probably along the lines of 1000
> lines and with a totally white background probably less. Addressable
> resolution means you can hit the exact area on the CRT but because of design
> limitations that are directly related to money you are also illuminated a
> whole bunch of other pixels in the area. You absolutely need some pixel
> overlap to get a smooth image but the lower price units have much more pixel
> overlap than more expensive units.
> David
>
> -----Original Message-----
> From: Rob Geraghty [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, September 26, 2000 7:52 AM
> To: [EMAIL PROTECTED]
> Subject: Re: Measuring resolution (was Re: Real resolution of a 4000
> dpiscanner?)
>
> Jim wrote:
> [snip]
> >the design of general purpose lenses. Even so, the scanner resolution
> can
> >be calculated but I do not have the equations in front of me. I will try
> >to find them.
>
> That would be great! Thanks!
>
> >The main thing is to get a good sharp image on the film.
>
> >From what David is saying, this may not be possible. A different
> test image will probably be necessary where the dominant "colour"
> is not white. I have a really good one I downloaded off the net
> but I think I can't reproduce it for distribution. I also may
> not be able to get the PC with the recorder to *load* such a huge
> file. The PC doesn't have a lot of RAM.
>
> All this *may* be irrelevent depending on the result from the
> recorder. In any case from my perspective what I was interested
> in was a consistent image which was made without lenses that
> can then be scanned to get an idea of film grain on different
> film types.
>
> Rob
>
> Rob Geraghty [EMAIL PROTECTED]
> http://wordweb.com
>
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