Re: Quoting EI

[George L Smyth <GLSmyth@xxxxxxx>]

Sandor Mathe wrote:
> 
> The main drawback (potentially anyway) of TTF meter readings is
> whether the light meter or more importantly your light meter versus
> mine react the same to the strong filtration of a 25 or 29 Red
> filter.  They likely react about the same to the 87 opaque :-)
[clip]

Actually, I feel that that is its strength.  What is the filter factor of a #25
filter?  It could be 2, 2.5 or 3 stops.  Your #25 filter could be very different from
mine, just as your meter could be very different.  By taking this from the mix, you
end up with a very simple measurement.

By requiring the addition of a filter factor, you also have to further consider the
scene.  How much blue is in the scene?  You will be filtering this from the scene, so
this metered light will not hit the film.  If the scene does not include a blue sky,
more of the metered light will be exposing the film.  Metering without the filter
requires that you make a judgement as to how much metered light will actually get to
the film.  Thus, what filter factor do you use?

The fact that we will be exposing the film not only to visible light (assuming a #25
filter), but also to radiation that our meters are not calibrated for, makes this a
difficult process.  Simplifying things to reduce the number of variables allows for
greater repeatability.

All this said, there are a couple of additional points that probably make this
discussion, for the most part, meaningless.

One is that if Elton's method works for him, then I am going to be the last person to
disuade him from what is a winning formula for him.  Regardless what anyone says, if
it works for him then he should continue doing what he is doing.

The other thing is that both methods will get one at least in the ballpark.  I've
shot HIE/HSI for many years and the most important thing I can say is "thank goodness
for variable contrast paper!"  When I am unsure about a scene, I simply bracket a
stop either way and (nearly) always end up with a negative that can be printed the
way I envisioned (this is not the case with EIR, with which I have had varying
results - from great to trashable).

george

- -- 
 Handmade Photographic Images     
  http://www2.ari.net/glsmyth/
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