Digital BW, The Print

Ahh...
You Wrote Austin:
"> It's more than a formula, it's an understanding."

OK!

"It's more than resisters, it's about understanding!"

Sorry... could not "RESIST".

Are you happy with what you see, fellows? 
Try everything you can buy, and don't "RESIST"!

Lux!
Bo Wrangborg
Swedish Team




--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Austin 
Franklin" <darkroom@i...> wrote:
> Claude,
> 
> > > The best you get is 100, the WORST you get is 50.  In reality, 
you get a
> > > range of 50-100.  The 50 would be called "RELIABLY".
> > >
> > > Austin
> > >
> >
> > Correct me if I'm wrong, but historically, haven't we put the 
lens MTF in
> > parallel with the film MTF? Like tow 100 ohm resistors in
> > parallel and invert the
> > sum of their inverses in the process? and is "reliably"/planning
> > for worst
> > case? According to this formula, if either of the MTFs is any
> > lower, the total
> > MTF would be less than 50, reliably. If there's a more accurate
> > formula, please
> > enlightent me.
> 
> Yes, electronically, 100 ohms in parallel with 100 ohms does give 
you 50
> ohms, but electronics are not the same as optics and film.  Film 
records the
> data just like a CCD array does, using discrete elements.  If the 
photons
> being "measured" happen to fall right on the sensing area, it will 
record at
> that resolution, if it happens to straddle two sensing areas, it'll 
record
> half that resolution.  What you will get are values from %50 gray 
on two
> adjacent sensing areas, to one %100 white and one %100 black (if 
you are
> using a test pattern that is).  Of course, film grain size is 
random, but
> still within a rather narrow size band.
> 
> It's more than a formula, it's an understanding.
> 
> Austin