Push, pull, contrast etc.

**** Post for FREE via your newsreader at post.usenet.com ****


I admit I became a bit puzzled about what 'push-processing' of film *in
reality* achieves (and, consequently, how to correctly shoot for
push-process).

Until now I have been convinced by many people that push-processing simply
increases sensitivity (and as a side effect, color saturation etc.). I have
been instructed - even by the lab stuff - to shoot at -1EV if i wanted them
to push-process the film. Results were usually really poor in shadows...
Overall "exposure" of the print was usually OK (I assume that because of lab
doing the corrections, and not as a direct result of push-processing). I
suppose I just hit the lower threshold of the negative.

But - aimed to improve my skills a bit - i have read a little stuff on the
zonal exposure system. Basically the rules as I understand them were like
'Shadow density is controlled predominately by exposure. Highlight density
is controlled predominately by developing time'. Putting 1+1 together my
assumption is that push-processing 1) increases contrast and 2) moves the
gray point one stop closer to the highlights. Which only by very very far
might be considered a "iso upgrade".

Can anyone elaborate or point me to something that explain push processing
correctly please?

My assumption now is that if I intend to push process (speaking of
lab-processed C41, no B/W@home) I:
- should expose "as usually" for shadows, *no* constant -1EV correction
- will get higher-contrast negatives, also more saturated colors
- will not get a higher-iso equivalent of the negative
- insert your own comments here


any hints appreciated!

--

deejay



-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
*** Usenet.com - The #1 Usenet Newsgroup Service on The Planet! ***
http://www.usenet.com
Unlimited Download - 19 Seperate Servers - 90,000 groups - Uncensored
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

"Tomas Daniska" wrote in message ...
**** Post for FREE via your newsreader at post.usenet.com ****


I admit I became a bit puzzled about what 'push-processing' of film *in
reality* achieves (and, consequently, how to correctly shoot for
push-process).

Extending development increases contrast (a lot) and usable speed
(only a little).


Until now I have been convinced by many people that push-processing simply
increases sensitivity (and as a side effect, color saturation etc.). I have
been instructed - even by the lab stuff - to shoot at -1EV if i wanted them
to push-process the film.

Why are you 'pushing' at all? The only reason to push is because you
HAVE TO.

Results were usually really poor in shadows...

OF COURSE! Who said otherwise?

Overall "exposure" of the print was usually OK (I assume that because of lab
doing the corrections, and not as a direct result of push-processing). I
suppose I just hit the lower threshold of the negative.


Are you pushing C41? That does not work. The color devlopment and
silver devlopment occur simultaneously, and when C41 is not processed
normally (at the correct time and temeprature) it causes color
crossover. Why? Because the three layers increase in contrast, but not
to the same degree! therefore, green shadows and magenta highlights,
etc. occur. Or blue shadows and yello highlights. Or cyan shadows and
red highlights.

DON'T PUSH C41 FILM.

FORGET ABOUT PUSHING. IT'S A WASTE OF TIME.

**** Post for FREE via your newsreader at post.usenet.com ****


Are you pushing C41? That does not work. The color devlopment and
silver devlopment occur simultaneously, and when C41 is not processed
normally (at the correct time and temeprature) it causes color
crossover. Why? Because the three layers increase in contrast, but not
to the same degree! therefore, green shadows and magenta highlights,
etc. occur. Or blue shadows and yello highlights. Or cyan shadows and
red highlights.

I never had not problems with color shifts on the pushed negatives. Only the
shadows were problem - and it seems to me that only due to invalid exposure
recommendations they gave me...

DON'T PUSH C41 FILM.

FORGET ABOUT PUSHING. IT'S A WASTE OF TIME.


then WTH Kodak says Portra/Supra push well one to two stops?


thanks anyway

--

deejay



-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
*** Usenet.com - The #1 Usenet Newsgroup Service on The Planet! ***
http://www.usenet.com
Unlimited Download - 19 Seperate Servers - 90,000 groups - Uncensored
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

"Tomas Daniska" posted:
"... then WTH Kodak says Portra/Supra push well one to two stops? ..."

For the same reason that car manufacturers advertise 160 mph cars!

"Tomas Daniska" wrote in message
...
snip

then WTH Kodak says Portra/Supra push well one to two stops?


it is my understanding that the Portra films will tolerate under or over
exposure of up to 2 stops and still yield a workable image, with the
standard film processing.

Ken Hart

"Tomas Daniska" wrote in message ...
**** Post for FREE via your newsreader at post.usenet.com ****


Are you pushing C41? That does not work. The color devlopment and
silver devlopment occur simultaneously, and when C41 is not processed
normally (at the correct time and temeprature) it causes color
crossover. Why? Because the three layers increase in contrast, but not
to the same degree! therefore, green shadows and magenta highlights,
etc. occur. Or blue shadows and yello highlights. Or cyan shadows and
red highlights.

I never had not problems with color shifts on the pushed negatives. Only the
shadows were problem - and it seems to me that only due to invalid exposure
recommendations they gave me...

DON'T PUSH C41 FILM.

FORGET ABOUT PUSHING. IT'S A WASTE OF TIME.


then WTH Kodak says Portra/Supra push well one to two stops?


NO film 'pushes' at all, let alone two stops.

From: (Michael Scarpitti)
Organization: http://groups.google.com
Newsgroups: rec.photo.darkroom,rec.photo.film+labs
Date: 24 May 2004 18:29:05 -0700
Subject: Push, pull, contrast etc.

"Tomas Daniska" wrote in message
...
**** Post for FREE via your newsreader at post.usenet.com ****


Are you pushing C41? That does not work. The color devlopment and
silver devlopment occur simultaneously, and when C41 is not processed
normally (at the correct time and temeprature) it causes color
crossover. Why? Because the three layers increase in contrast, but not
to the same degree! therefore, green shadows and magenta highlights,
etc. occur. Or blue shadows and yello highlights. Or cyan shadows and
red highlights.

I never had not problems with color shifts on the pushed negatives. Only the
shadows were problem - and it seems to me that only due to invalid exposure
recommendations they gave me...

DON'T PUSH C41 FILM.

FORGET ABOUT PUSHING. IT'S A WASTE OF TIME.


then WTH Kodak says Portra/Supra push well one to two stops?


NO film 'pushes' at all, let alone two stops.

Another one of Scarpathetic's lies. Glad he got kicked of photo.net, too
many newbies getting erroneous information.

Michael Scarpitti wrote:


NO film 'pushes' at all, let alone two stops.

Wrongo ago wonderdog.


--
--e-meil: there's no such thing as a FreeLunch.--

Tomas Daniska wrote:

I admit I became a bit puzzled about what 'push-processing' of film
*in reality* achieves (and, consequently, how to correctly shoot for
push-process).

Until now I have been convinced by many people that push-processing
simply increases sensitivity (and as a side effect, color saturation
etc.). I have been instructed - even by the lab stuff - to shoot at
-1EV if i wanted them to push-process the film. Results were usually
really poor in shadows... Overall "exposure" of the print was usually
OK (I assume that because of lab doing the corrections, and not as a
direct result of push-processing). I suppose I just hit the lower
threshold of the negative.


But - aimed to improve my skills a bit - i have read a little stuff
on the zonal exposure system. Basically the rules as I understand
them were like 'Shadow density is controlled predominately by
exposure. Highlight density is controlled predominately by developing
time'. Putting 1+1 together my assumption is that push-processing 1)
increases contrast and 2) moves the gray point one stop closer to the
highlights. Which only by very very far might be considered a "iso
upgrade".

Can anyone elaborate or point me to something that explain push
processing correctly please?

My assumption now is that if I intend to push process (speaking of
lab-processed C41, no B/W@home) I: - should expose "as usually" for
shadows, *no* constant -1EV correction - will get higher-contrast
negatives, also more saturated colors - will not get a higher-iso
equivalent of the negative

You got that last bit just right. Don't be shy over a 1 or 2 push, and
for those who bemoan the color shifts, too bad... better to have the
shots than not.

First of all, one should choose the right film for the right situation,
and if that can't be done (for a variety of reasons) then we resort to
pushing. One example is dim light photography. You got some 800 film,
but you want to do some short shutter time, handheld shots in dim light.
So rate it at 3200 and push 2.

The general formula is rate the film for underexposure (an ISO 400 film
loaded, the ISO setting at 800 ... it will get under exposed by one
stop) ... then instruct the processor to "push 1". (Here in Quebec it
is "boost 1" for some reason).

Okay? Well no. It turns out that the 1 to 1 pushing for underexposed
film is not quite right for all films.

EliteChrome 200 for example. Pushes very nice, but the EI (exposure
Index) should not be one to one with the processing... rate it at 320
and push 1 (eg: under expose by 2/3, but push 1).

....rate it at 640 and push 2.

A common practice with Portra 160 is to over
expose it by 2/3... EI at 100. But no 'pull' processing is required.
It just looks best this way (of course taking advantage of the
overexposure tolerance of the film).

Many shoot Velvia at 40 'stead of 50... they want the saturation lowered
a bit (slide film here) and the slide 'thinned out'. No 'pull' during
processing is applied.

[BTW: It is best, where equipment allows it, to use the ISO setting to
EI the film, leaving EXP COMP for those individual frames where the
meter needs compensation due to scene reflectivity...]

Cheers,
Alan
--
--e-meil: there's no such thing as a FreeLunch.--

In rec.photo.darkroom Alan Browne wrote:
: Michael Scarpitti wrote:

:
: NO film 'pushes' at all, let alone two stops.

: Wrongo ago wonderdog.


While I agree with scarpitti about the effect of extended development on B&W film
having no significant effect on film speed. I do know that Kodak advertises that
their Ektachrome 200 is a "pushable" film.

I'm not sure what to do. Do I believe scarpitti or Kodak??
--




Keep working millions on welfare depend on you
-------------------