120 film looks thin?

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k - 09 May 2004 09:22 GMT

I've been developing some 120 film and it seems as if the negatives come out
thin.
the edge texts look right but i always seem to have seemingly low contrast
negatives.

I use the same developer / times as my 35mm film, however I notice I dont
get the same contrast
as 35mm

is 120 film supposed to look less contrasy than 35mm???

k.

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Francis A. Miniter - 09 May 2004 16:24 GMT

Hi K,

120 film is not supposed to look thinner. I suspect the problem lies
with the use of two different light meters. The light meter you are
using with the medium format camera is telling you there is more light
than is actually there, so you are giving the negative less exposure.
Do a head to head comparison of the two light meters to see if this is
correct.

Francis A. Miniter

>I've been developing some 120 film and it seems as if the negatives come out
>thin.
[quoted text clipped - 8 lines]
>
>k.

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Don James - 09 May 2004 18:38 GMT

> I've been developing some 120 film and it seems as if the negatives come out
> thin.
[quoted text clipped - 4 lines]
> get the same contrast
> as 35mm

But you're using a different camera. Maybe the exposures aren't the
same due to metering, shutter speed error, etc. Is the shadow detail
comparable to what you get in 35mm? You may have to adjust your
exposures based on the behavior of the equipment.

> is 120 film supposed to look less contrasy than 35mm???

Have you printed any of the negatives to see if your judgement about
the contrast is accurate? Maybe looking at a larger negative is
throwing off your perception of the contrast.

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arnold henri - 14 May 2004 13:17 GMT

35 mm and 120 rolfilm is NOT the same film :

35 mm have a special coating on the back of the film to avoid reflections in
the emulsion
120 film does not have this coating because it is backed with blackpaper.

As a general rule, you should develop 120 film longer

> I've been developing some 120 film and it seems as if the negatives come out
> thin.
[quoted text clipped - 8 lines]
>
> k.

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Jim MacKenzie - 14 May 2004 15:49 GMT

> 35 mm have a special coating on the back of the film to avoid reflections in
> the emulsion
> 120 film does not have this coating because it is backed with blackpaper.
>
> As a general rule, you should develop 120 film longer

If the coating is on the back of 35mm film and the emulsion is on the front,
why would extended development be required for rollfilm?

Jim

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Richard Knoppow - 15 May 2004 00:40 GMT

> 35 mm and 120 rolfilm is NOT the same film :
>
[quoted text clipped - 5 lines]
>
> "k" <asdf@asdf.com> schreef in bericht

news:nTlnc.472581$2oI1.240610@twister01.bloor.is.net.cable.rogers.com...

> > I've been developing some 120 film and it seems as if the negatives come
> out
[quoted text clipped - 9 lines]
> >
> > k.

35mm film may look denser because the _support_ has a
pigment in it to prevent the condution of light laterally
through the support. It also has an anti-halation funtion
but 35mm film is usually back coated with an anti-halation
dye. The difference is the pigment used in the support since
both kinds of films have a back coating. The back coating is
gelatin. It serves two purposes, one is to reduce curling of
the film because of the differential shrinkage of the
emulsion. The back coating is supposed to shrink abuot the
same amount to counter the curling. It sort of works. The
other purpose is to carry the anti-halation dye. This dye is
decolorized in the developer and also in the fixing bath.
Some of it also washes out. The result is that the _backing_
is clear after processing. The anti-light-piping pigment in
the support of 35mm film is neither decolorized or washed
out so the support looks gray. color films do not have this
pigment. Instead they have an anti-halation layer coated
under the emulsion layers, perhaps as part of the subbing.
As with the back coating the dye is decolorized in
processing so the support looks clear. Since this layer is
inbetween the support and the emulsion no pigment is needed
in the support. The reason 35mm films have the
anti-light-piping pigment is that sometimes one end is
exposed to fairly strong light, as when film in a cassette
is being loaded. The pigment in the support prevents light
from being conducted through the support causing fogging.
Agfa B&W films seem to have an anti-halation layer under the
emulsion similar to color films. There is still a gelatin
back coating on films with the anti-halation layer under the
emulsion to act as an anti-curling layer.
Now, that said, the measure of a negative is its printing
qualities. If the negative prints on normal grade paper with
good contrast, and has good shadow detail, its not thin. For
some reason some films can look thin and print perfectly. My
experience with T-Max films indicates they are like this.
Some developers (Microdol-X when used full strength for
example) leave the image a slightly brown color which can
look a little thin but print normally.

Signature

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com

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