Programming colour analyzer for different films. Why?

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Nick Zentena - 08 May 2004 16:18 GMT

This maybe a simple question with an obvious answer but here goes.
I understand why you need to program for different papers/chemicals but why
for different films? If the analzyer knows that so much light of a certain
type turns the paper grey [or whatever it's programmed for] then how does
the film enter into this? Isn't the film just filtering the light?

Nick

Reply to this Message

Donald Qualls - 08 May 2004 18:54 GMT

> This maybe a simple question with an obvious answer but here goes.
> I understand why you need to program for different papers/chemicals but why
[quoted text clipped - 3 lines]
>
> Nick

The problem is that the film's filter curve and the analyzer's
sensitivity curve(s) may match up in different ways for different brands
of type of films. If Brand Q film has filtering with a strong notch
just at the valley between the analyzer's red and green channels, but
your paper/developer chemistry is strongly sensitive at that wavelength
because of different internal filtering and sensitizers, you could wind
up wasting a lot of paper trying to get a good print while your analyzer
swears up and down you should be done and gone to lunch -- where you'd
have no problem with Brand X film, which uses a different dye in the
base, looks the same to the eye but lacks the "notch" and so prints
without a problem.

So, the analyzer's channels have to match the film's filter(s) as well
as the paper's sensitivity and filter layer(s). This is probably less
of a problem if you use film, paper, and chemistry all from the same
manufacturer -- but even then, your analzyer might miss information
that's important if it's not programmed to match the characteristics of
the film as well as the paper.

Of course, there are a lot of operators who print color without an
analyzer and produce perfectly fine prints -- but it takes a practiced
eye without a trace of dichromatism.

Signature

I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

Reply to this Message

Nick Zentena - 09 May 2004 14:51 GMT

> Of course, there are a lot of operators who print color without an
> analyzer and produce perfectly fine prints -- but it takes a practiced
> eye without a trace of dichromatism.

Ya my old analyzer isn't working right so I've been doing everything by
eye. But I've just bought a "new" one for $12. The new one mentions the need
to reprogram for different films while the old one claimed to be able to
handle different films. All I really want is the exposure metering part. I
don't use a lot of different films and an even smaller number of papers so
filtration isn't that big of an issue but being able to get the exposure
close intially would be a plus. If nothing else it saves me from times like
today when I accidently set the lens at F/11 instead of F/5.6. I knew it
looked too dark on the easel-)

Thanks
Nick

Reply to this Message

Jim Phelps - 11 May 2004 17:30 GMT

> > Of course, there are a lot of operators who print color without an
> > analyzer and produce perfectly fine prints -- but it takes a practiced
[quoted text clipped - 12 lines]
> Thanks
> Nick

Nick,

It might work. But what Don was saying may result in good exposure for
the color you analyzed.

Said another way; If you're analyzing a 18% gray card (or any color
common to both films), you get a correctly exposed and printed picture.
This is the film/paper combination you programmed the analyzer for.

If you use a different film (not so bad within the same manufacturing
family, even less of a problem with in the same line like, Kodak Portra),
and again have that venerable 18% card in there and analyze it, you're 18%
should be well exposed but due to the density curves of the three (or four)
emulsions, you may get a sadly washed out yellow and a (unnaturally) dark
blue sky (for example).

The same holds true for the other colors. The three (or four) different
dye layers are not going to be balanced from film manufacturer or film line
to another. They may be close, but I've noticed huge differences between
older films like Kodak's Vericolor III S and it's stable brother Ektar
(sister? I just don't know if film is gendered F or M :~). That gray card
looked good in both prints, but the rest of the print was utter garbage. I
can imagine it would be much worse between Green and Yellow.

So to answer your question; Yes, you must analyze for different
film/paper combinations. A real pain in the bottom when you have a single
channel analyzer. Keep saving, even ColorLine 5000 or 5100's are going for
reasonable prices on that auction site...

Jim

Reply to this Message

Nick Zentena - 11 May 2004 19:05 GMT

> So to answer your question; Yes, you must analyze for different
> film/paper combinations. A real pain in the bottom when you have a single
> channel analyzer. Keep saving, even ColorLine 5000 or 5100's are going for
> reasonable prices on that auction site...

Hi,

My old one is a Colorstar 3000. The colour part doesn't work. Every so
often I try and find some one willing to fix it but the most any one is
willing to do is ship it to Europe. No one is willing to even give me an
estimate on the repair. I keep my eye out on a replacement but I'm getting
better at doing things without it. The anaylzer would make me quicker and
save some on paper/chemicals. So I keep looking but I worry that the
replacement I might buy is broken like mine-)

Thanks
Nick

Reply to this Message