[rollei_list] Re: Slide film is alive with filtration
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Fri, 22 Feb 2008 10:29:23 -0800
----- Original Message -----
From: <Choiliefan@xxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Friday, February 22, 2008 7:23 AM
Subject: [rollei_list] Re: Slide film is alive with
filtration
> Richard,
> I know it should be elementary by now but the puzzle is
> whether I use the
> same color correction filters for transparency film as I
> do for negative stock?
> I understand the polarizer and filters for B&W but having
> not shot much
> serious color the basics are not ingrained into my
> knowledge base.
> It's surprising that despite having shelves of basic
> photography books, very
> little quick useful information is at hand regarding this.
> Perhaps there
> isn't a difference be it neg or slide? Does a blue 81A
> work the same way in
> incandescent light?
> I'm completely flummoxed and bewildered...
> As usual, any help is greatly appreciated!
> Health, Peace
> Lance
> Selma, NC 27576
>
OK, I can understand this. So far you have gotten
several replys and I don't want to restate things. However,
both types of films see similarly and are fixed in their
response to color. The eye makes automatic and continuous
adjustment for the average color of the scene. This is not
just color temperature of the predominant light but also
just having a lot of a given color will shift the balance of
the eye so visual judgement can be misleading.
Note that the color temperature (or lets simplify and
just say color) of "daylight" varies all over the place.
Late afternoon sun, especially in the lower latitudes and in
winter can be very yellow and skylight is very blue. If you
are shooting under conditions where the sky is clear and
part of the subject is illuminated by clear skylight it will
reproduce very blue while areas in direct sunlight will be
correct. The late afternoon condition described above may
result in very warm or even yellowish colors for objects in
direct sun and very blue effects for parts in the shade.
There is no simple way to correct for both at the same time
because a single filter will shift the color of _all_ the
light coming into the camera.
A polarizing filter will not be of much help because
although it will darken the sky it will have little effect
on skylight reflected from non-polarizing materials such as
skin and cloth.
Perhaps the best solution is to use a UV filter, which
will tend to reduce sky illumination to some degree along
with fill flash. The flash will tend to warm up the shadows
especially if a slight warming filter is placed over it. Of
course, this is for portraits and other close work and won't
work for distant objects.
About the only difference between negative and
transparency materials may be the relative tracking of the
color into the shadows. Ideally color film should track the
three colors perfectly so that a gray scale remains neutral
for all values, however, some films tend toward warming up
the shadows and others toward cooling them off. If you know
what the film will do you can choose accordngly but modern
color films are pretty good at tracking.
Of course, I am leaving out the possiblity of using
electronic means or of using photographic printing masks to
make corrections. Both methods can be successful but both
take some skill.
Now, if the overall color is wrong rather than just
shifting due to skylight a correction filter can be chosen
to correct or partially correct the result. Daylight color
films are generallly balanced for "average daylight" a color
temperature of around 5500K to 6000K. Tungsten films are
balanced for either 3200K (pro films) or sometimes 3400K
(floodlights). To correct daylight one can choose either a
warming or cooling filter as you think is needed. A color
temperature meter may help since, as pointed out above, the
eye is simply not a reliable judge of color.
I am not sure what references to suggest since a lot of
publications I used to rely on are no longer available but a
search of Kodak's stuff may find something.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
---
Rollei List
- Post to rollei_list@xxxxxxxxxxxxx
- Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe'
in the subject field OR by logging into www.freelists.org
- Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with
'unsubscribe' in the subject field OR by logging into www.freelists.org
- Online, searchable archives are available at
//www.freelists.org/archives/rollei_list
Other related posts:
