# theory question

Discussion in 'Photography' started by Diluted, Oct 11, 2004.

1. ### DilutedGuest

If I was to shoot some film without a polariser, would I be able to use one
on the enlarger to make the colours richer when printing?
Obviously it wouldnt effect things like reflections, but would it alter the
colours or what would happen?

if it wouldnt work, why not, and what would happen?

just wondering

Diluted, Oct 11, 2004

2. ### andreGuest

So far for theory. In reality the film will saturate and you will have
lost detail that you can not bring back during post processing of any kind.

Andre

andre, Oct 11, 2004

3. ### Carlos MorenoGuest

No, it won't work at all.

A polarizer takes advantage of the fact that light waves
reflected off a flat/shiny surface has a particular orientation
(when I say orientation, think of the waves in the surface of
the sea or a swimming pool -- they oscillate up and down, as
opposed to sideways; that's what I mean with the "orientation";
the technical term is, not surprisingly, polarization).

So, the polarizer filter only lets through waves that have a
particular polarization -- you turn it to adjust which sense
you want to block (i.e., to align the filter with the surfaces
that are sending unwanted glare). But once those waves reach
the film chemicals or the sensor cells (depending on the type
of camera), the amount of light is "measured and recorded".
The fact that such light had a particular polarization is not
"recorded", and thus the information is lost.

When you're processing the negatives or digital image, there
are no reflections to be eliminated -- there is light with a
pattern equal to the one you see off a glaring surface, but
it is no longer a glaring surface.

So, no, the trick won't work. Same thing should be true for
most filters -- they normally take advantage of features that
are present in the actual light waves you're catching; after
that light was caught and recorded, a lot of information is
"lost" (it is discarded at some point in the process of
"recording" that light pattern), and often that information
is the one that the filters take advantage of.

HTH,

Carlos
--

Carlos Moreno, Oct 11, 2004
4. ### DilutedGuest

cheers, just wondering.
I havent exposed any film without polarising, but i thought it best to ask
before trying it and hoping it worked

thanks

Diluted, Oct 11, 2004