Zone System & Reciprocity Failure

Hello all,

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I've just moved up to LF from MF and have got to get used to the joys of non-TTL metering again. I have some idea on the workings and aims of the zone system but as I generally take architectural shots inside dark / dingy churches, I have to compensate for reciprocity failure. I'm using B&W negative film, usually Delta 100. My problem is understanding whether the reciprocity correction makes any difference to the negative contrast and, if so, how to get around it. For example, I might have a 5 stop contrast range in a picture, I can meter for the highlight and put it on zone viii or meter for the shadows and put it on zone ii and get an equivalent zone v reading. (I suppose I should use the shadow reading to get to zone v reading rather than the highlight reading with respect to the "expose for shadows, develop for highlights?") Do I then just add on the reciprocity compensation for this zone v reading or do I have to do something else?

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Any help appreciated if you can understand the above. Thanks.

A good starting point for you might be Using The View Camera by Steve

Simmons. In it he has a table of reciprocity corrections and

recommended development time adjustments. The way I've been doing it

is to meter the shadows and place them in zone 3 then adjust dev.

time according to the contrast range after adjusting for reciprocity.

In other words I might reduce dev time by 5% for reciprocity then 15%

for n-1. But as I am still a LF rookie my times are still being

experimented with.

Rob

Thanks Rob, it looks like I'll have to carry on with cutting the

development time. I've used approx 10% less to date but that was with

my Bronica and I knew the lenses were contrasty as well as the light

via my previous metering technique (meter and expose for shadows and

try to get the highlight detail back via development and split grade

printing) which, overall, is trying to rescue high contrast negs. I

need to get enough shots done to do a proper LF test instead of

giving myself printing headaches.

Reciprocity will influence negative contrast. The reason is that the

highlights are less affected by reciprocity failure than the shadows.

Exposure, though is typically based on shadows to ensure adequate

density in the shadows. However, what you place on Zone VII may not

need any reeciprocity correction (or less than required in the

shadows). The nett result is that what you place on Zone VII is

actually higher on the scale. Typical advise given is to increase

exposure by about a stop beyond 1 second exposures, by 2 stops beyond

10 seconds and by 3 stops beyond 100 seconds (these are just rules of

thumb - its worth checking your film's data sheets). Corresponding

changees to deevelopmeent are 10% less, 20% less and 30% less. Again,

worth testing. Good luck. DJ

I have a reciprocity table on a label on my lightmeter. It is for HP5+

to be developed in PMK and beginning at 8 seconds (which adjusts to

19" seconds) I deduct 5% of development time. That is, I deduct 5%

after deciding which time (i.e., which zone) in which to place the

highlights. The far end of the table is 4 minutes adjusted to 3 hours,

10 minute and minus 30% of development time.

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Don't know what I'd do if I wanted to do N-3 (about 5 minutes I think)

and also needed to deduct 30% of that time!? But I cannot think how an

extremly high contrast scene would need such a long exposure anyway.

<p>

The bottom line is you do need to take both elements into account in

turn. It is analogous to bellows factor plus a filter factor.

Gentlemen;

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Reciprocity failure is the breakdown in the linear relationship

between aperture settings/film in regard to it's ability to record

detail. Corrections for long exposures must be done IN THE CAMERA, by

increasing exposures. Adjusting development will do nothing for a

negative that is underexposed due to lack of correction in exposure.

Matt, reciprocity also have an effect on the negative contrast.

Because the shadows on the negative are hit by light of less intensity

than the highlights, they are more affected by reciprocity failure.

Thats why the contrast of the neg increase, and we need to shorten dev

time to compensate

I have several generic reciprocity tables for all films other than T

Max (T Max films have their own reciprocity tables since they are

less affected by reciprocity failure than other films). These tables

were taken from several sources (a workshop, a magazine article).

I've been using them for several years with HP5+ film and they seem

to work well. FWIW, these tables show the following effect of

development on reciprocity failure: no change in developing time

until the metered exposure is 15 seconds (resulting in a 27 second

exposure to take reciprocity failure into account). If developed

normally, the resulting negative will be the equivalent of N + 1/2 so

you reduce development accordingly (unless, of course, you want N +

1/2 contrast in the negative). When the metered exposure is 30

seconds, the actual expsoure time is one minute and the resulting

development will be the equivalent of N + 1 so again you reduce

development time accordingly (unless you want N +1 contrast). If the

metered time is 2 minutes, the actual time is 6 minutes and the

resulting development will be N + 1 1/2. If the metered time is 4

minutes, the actual time will be 15 minutes znd the resulting

develoment will produce the equivalent of N +2. If the metered time

is 8 minutes the actual time will be 35 minutes and the resulting

development will be the equivalent of N + 3. That's as high as my

tables go. You exrapolate for times in between these times.

Andrew:

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Just because the increase in exposure necessary to compensate for

reciprocity law failure in the shadow areas will cause an increase in

the overall contrast of the negative does not necessarily mean that

it will be necessary to reduce development times. As a matter of

fact, I have found a number of situations where an increase in

development time was called for because the increase in contrast was

inadequate to provide adequate overall desity range in the negative.

It is not unusal to find a dimly-lit scene that does not have an

adequate brightness range to provide the wanted density range in the

negative even after the increased negative contrast resulting from

the compensation for reciprocity law failure.

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Let me give you an example. Say you have found a dimly lit scene

that has shadows that are placed on Zone III of the exposure scale.

Let us also say that the highlight areas of the scene fall only on

Zone V (this is not unusual since a lot of dimly lit scenes are also

rather softly lit). Let us say (for purpose of example) that this

Zone III placement indicates an exposure time of 1 second at whatever

f/stop we have elected to use (we MUST expose correctly for the

shadows since, if we don't get the detail there through exposure, we

won't be able to get it there at all). If we are using a

conventional type of B&W film, we would probably find it necessary to

give 2 seconds of exposure in order to compensate for reciprocity law

failure in the areas of the projected image that fall in Zone III or

lower.

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Now, let's take a look at what is going to happen in the areas of the

projected image that will fall in Zone IV and higher because of our

Zone III placement of a particular shadow area. Since these brighter

areas of the scene are at least one stop brighter than the Zone III

area, these areas would have indicated an exposure of 1/2 second or

less if they had been placed in Zone III. Therefore, these higher-

falling Zones will not suffer from as much reciprocity law failure.

As a matter of fact, in this particular example, they will, for all

practical purposes, suffer from no reciprocity law failure at all.

When we give a 2-second exposure to our negative, the areas falling

in Zone IV and higher will actually get a full 2 seconds worth of

exposure while the areas in Zone III and lower will get only 1 second

worth of exposure.

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The result of this will be that the areas falling in Zone IV and

higher will get 1 additional stop worth of exposure. This will cause

these areas of the negative to gain about 1 stop worth of additional

exposure and resultant density. In other words, the highlight areas

of our scene that fell in Zone V will get moved up to Zone VI. We

must now determine if this resulting Zone VI density is appropriate.

If we feel that it is correct, then no compensation in developing

time is necessary. If we feel that the highlights should fall higher

than Zone VI, then we must increase our development time. If we feel

that the highlights should be darker than Zone VI (possible, but

unlikely), we would then (and only then) reduce our development.

<p>

This is only an example of a single situation where reduction in

development times could be disasterous! There are, however, some

situations that will absolutely require a reduction in development

times. In those situations, failure to do so can also be

disasterous! And there are situations that will require no

compensation in development time at all. What all of this means is

that each situation encountered must be analyzed individually and

handled individually. There are no rules-of-thumb that apply to all

situations.

Thanks for everybody's answers so far.

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Brian: From the reciprocity corrections and contrast increase, I'd

assume that if a 30sec metered exposure plus reciprocity gave an N+1

contrast level, developing at N-1 would bring the contrast back to

normal? I have an Ilford data sheet and have calculated the

reciprocity curve but never really used the contrast / time curves

apart froma a blanket "knock a minute off to stop developing the

highlights." (Also, is N+1 the same as producing a contrast

equivalent to 1 grade higher on multigrade / varicontrast paper?)

<p>

Ken: I understand your reasoning about wanting to increase

development times if you have a flat subject to create contrast, i.e.

forcing tones to lie on more separated zones. The problems I normally

encounter are trying to flatten the contrast in a scene. My scenarios

usually involve the dimly lit church having a dark oak altar below a

stained glass window (hopefully I'm taking pictures on an overcast

day but it doesn't always work out like that and I have to try to

stop the window burning out and still get the shadow detail on film

as you say - if it isn't there, you can't print it in.

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At the moment I'm using a roll film back on the camera. It looks like

I'll have to go to sheet film for some trials as I can't afford some

more backs to label each one for different development / contrast

settings. I'll have to dig out the old grafmatic backs.

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Andrew

Andrew:

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Yes, the situation you described is most definitely going to have an

excessive range of overall brightness. In this type of situation,

exposure will be extremely critical since any underexposure at all

will result in total loss of shadow details. I would definitely

advise basing the exposure on Zone III areas or lower. Such exposure

will defintely dictate compensations for reciprocity failure. With

some careful analysis of the particular situation you are dealing

with, you should be able to accurately predict the ultimate Zone

placement of the highlights.

<p>

Whether you shoot on a cloudy day or a sunlit day could turn out to

be quite critical in determining you success. If you work on a

sunlit day it is quite possible that N-1 or even N-2 development

could still be quite excessive. Have you worked with any

manipulations in your development techniques? Agitation, dilutions,

etc?

Ken,

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I've always used ID-11 at 1:1 dilution and developed for 9 mins (10

mins standard time) to try to reduce the highlights. Other than that

I tend to stick to the indicated agitation periods / durations and

temperatures.

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I'd seen a report or two about the Barry Thornton DiXactol single /

two bath developer but haven't tried it. On his instructions he

mentions that N+1, N-1 isn't easy to control via time due to chemical

exhaustion and to use dilution instead. This could be another option

for me to investigate at some point.

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As for the sunlight level, I sometimes can't win. The best time is

when it's either very foggy or throwing it down with rain. The

problem then is that in the larger cathedrals, people come in for

shelter and long exposures are a pain as there's too many people

around. As I have to work for a living (not in photography) I can't

get to places during the week when it would be quieter.

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Andrew

I was thinking about your subject matter. Have you considered trying

some double exposures? Take the first picture in daylight and metre

for the hihglights (the windows) then wait for night fall and do the

second of the interior (lit by interior lighting) You would probably

still have some reciprocity failure to deal with but you should get a

much more normal contrast range. Rob

Try some pre-exposure and place the shadows on Z4 because the shadows

will lose density when you contract your development. Use a low

contrast developer or dilute developer. You can also use an old

emulsion film such as fp4 or TriX and use stand development to try and

build your shadows to their fullest extent while keeping your

highlight densities under control. On top of that try making a

contrast mask for those pesky windows and then print at a higher

contrast to help bring out the detail in the shadowed alter. You can

also use some selenium toner on the shadows to help build density so

the contrast range between the highlights and shadows is lessened. Or

try PMK Pyro which will develope with a stain which will self mask

some of the shadows. You can also bleach some of the dense highlights

on the neg. But I would go to sheet film and process accordingly. I

use a lot of pre-exposure to help tame highlights when the contrast is

+1 or less. But if you are going to use a development strategy that

calls for decreased development or stand development, be sure to give

the neg extra exposure to protect those important shadows. You've got

10 usable stops of curve so use it. james

Rob,

I'd never really considered double exposure due to the logistics of

a) being able to stay in a cathedral until after dark (unless you go

in November etc where closing time is after dark) b) having to leave

the camera set up in position for so long without it either being

moved (probably having the tripod kicked) or c) sombody trying to

steal the camera. As I'm not a professional, I'm not able to pay to

keep these places open to take a single exposure :-) but thanks for

the idea. Another downside to this is the actual internal lighting of

some of these places - it's worse than no lighting due to the harsh

shadows and hotspots etc. At some places I've had to ask them to turn

the lights off to give me a chance to even up the distribution. The

people then think you are weird by wanting the lights off to take a

picture.

<p>

James,

One of the ways I've been trying to "rescue" negs is to use pre-

flashing of the paper and split grade printing but it's not ideal.

Were you meaning pre-exposing the film intead? You've given me a lot

of ideas with the other things to try. My dad always sticks to FP4+

and I tend to think his negs are grainier and flatter compared to the

Delta 100 but it looks like I'll have to swap films. Unfortunately he

has the same problems with contrast as well but his negs look better

to start with. His were also possibly flatter due to the old lenses

he was using unlike my Bronica ones.

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Andrew

Andrew:

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These types of situations you are dealing with are some of the

toughest ones to be found. The dark areas inside the church suffer

from extreme problems with reciprocity law failure while the

highlights in the windows do not suffer reciprocity problems at all.

The areas of the negative that have recorded the darker areas of the

church interior probably need all the exposure and development they

can get while the highlights of the windows need as little exposure

and development as possible.

<p>

The pre-exposure (or post-exposure) that has already been mentioned

will help quite a bit with the additional exposure needed in the

shadow areas. For development, you might want to consider using a

highly compensating developer along with techniques that further the

compensating effects. I like to work with highly diluted developers

along with minimal agitation. One technique that I use is called the

1:4:1:4:1:4:1. You develop the film in a highly diluted compensating

developer (such as Edwal FG7 diluted 1+31 with water only) for 1

minute with only 10 seconds of agitation. At the end of the minute

in the developer, the film is gingerly transferred to water where it

remains for 4 minutes without agitation. The film is then returned

to the developer where the cycle begins again. In extremely

contrasty situations, the last minute in the developer can be

omitted. In situations that aren't quite contrasty enough, another

1:4 cycle can be added.

<p>

This method has worked quite nicely for me in situations similar to

yours. I would recommend a little experimentation before using it

seriously to get the details worked out right. This approach, though

it works nicly with roll film, is easiest to work with if you use

sheet films that can be developed individually.

Ken,

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Thanks for your suggestions - it seems as though you have the same

problems.

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I don't know whether Edwal FG7 is available in this country (England)

as it seems to be a US manufactured / sold item. I'll have to try and

find an alternative unless you know of one. We don't have anything

like the choice you have (assuming you're in the US.) Either that or

I'll have to try tapping up a few of the chemical wizards I know and

see if they can concoct an alternative.

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I suppose whilst I'm experimenting, rollfilm might be a bit easier to

handle as it would stay in the tank all the time to hopefully avoid

damaging the emulsion I presume you mean rather than transferring the

sheets between different baths etc.

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From your 1:4 cycle, should the last bath be a developer one or water

or doesn't it matter as the film is going to be put in stop-bath

anyway? I guess it's a suck it and see thing found out with trials.

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Andrew

Andrew:

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Yeah, I'm over here on this side of the Atlantic. I'm not familiar

with the chemicals and suppliers you have to pick from over on your

side. I would think that Tetenal would have something that is fairly

equivalent to FG7. Maybe Paterson would too. I've even heard of

some people using Kodak's D76 for the process, but I've never tried

it myself with D76.

<p>

Basically you need to use a developer that will become exhausted

rather quickly in the hightlight areas of the negative but will still

provide full development in the shadow areas. Of course, that is

exactly what a compensating developer does. Many developers will do

just that if they are highly diluted. Even HC110 will do it if it is

diluted enough. However, you need to be careful that there is enough

of the working developer for the quantity of film you are developing.

<p>

As far as the 1:4 cycle goes, it doesn't really matter which is the

last step, developer or water. I have found that it takes at least

three full 1:4 cycles, but in some cases you might need more cycles

than that. You,ll need to do a little experimenting to fine tune it

to your particular situation. As a matter of fact, with a little

careful metering and note-taking you could probably come up with a

system of matching different scene brightness ranges to the required

number of 1:4 cycles.

<p>

Good Luck!

Andrew, Try pre-exposing the film. You will boost the shadows enough

to lessen having to use such long exposures for reciprocity departure.

Also by using the middle part of the curve(zone4 for the shadows) you

won't have such a hard time in printing the negs. Using zone 3 and

then trying to keep the shadow densities intact is hard. Using zone 4

or even zone 5 gives you some nice shadow densities to work with when

you go to print. Now all you need is to keep the highlight densities

from going to high which can be accomplished by using either a water

bath with old emulsion type films or compensating developers with

delta or Tmax films. There are myriad ways to do this. Divided d76 or

rodinal at high dilutions will work fine. James

James, I once tried pre-exposing the film with the Bronica. It made a

slight difference to the shadows but only slight. I found I could get

more useful results from pre-exposing / fogging the paper and it was

a lot less hassle over having to rewind the roll film etc. I suppose

it's better to do the film as it makes printing easier as opposed to

having the same contrasty negs and trying to rescue them via the

paper. I'll have to get hold of some sheet film and try that.

<p>

I've just developed my first roll out of the LF camera tonight using

zone system metering (shadows placed on z3) and my usual developing

sequence. Apart from the pictures not being sharp (as I said, I'm new

to LF!), the density doesn't look as bad as some of the ones I've

done previously although they aren't the most contrasty of subjects.

There could be some hope :-)

<p>

Ken, I'll look around over here for some developer to try something

different to ID-11 if I can't get any joy with weaker dilutions.

<p>

Andrew

Andrew, remember that the better the neg the easier to print. Dom what

ever is neccasary to get a good neg because it easier than trying to

salvage a bad neg. You end up wasting paper and chemistry and you

never are able to calibrate your entire system properly. So when you

come across an great scene or come up with a great idea, you struggle

to bring forth all that it could be. James

Get Phil Davis' <em>Beyond the Zone System</em>. There is a chapter

near the end on miscellaneous topics such as reciprocity failure. If

I recall correctly, he says that sometimes, with some film and

developer combinations, contrast can actually <em>reduce.</em>

<p>

Like for your non-reciprocity-failure exposures, you ultimately want

to characterize your exposure and developing process through testing.

<p>

Of course, if you don't mind resorting to using variable contrast

printing, and a little lack of predictibility, you can use the

guidelines for developing reduction for your film and developer

combination and get into the ball park.

Thanks to everybody for the all the replies, suggetions, hints and

tips. It looks like I've got a fair amount of reading and testing to

do and hopefully I'll be able to sort out some of my "difficulties."

<p>

Andrew

The previous answers indicate the connection between reciprocity and

development. What I use is the following:

If the indicated meter reading is 1-4 s, and I then figure out the

time I should use, I regard that as N-1/2

If the indicated meter reading is 8-60s, and tthen I figure out the

time, the development is N-1;

indicated meter reading=1-4 minutes, Dev. is n-1 1/2;

Indicated meter reading is 8m-60m, development time is N-2.

Neat thing is that if the dynamic range of the scene is low--ie you

would need a + dev. time to start with, you can use the excessive

contrast reciprocity causes to your favor and adjust the dev. times

appropriatey.

Hope this helps.

Bob

Hi Andrew - In response to the question you asked me, yes, if the

extended exposure necessary to take reciprocity failure into account

will produce the equivalent of N + 1 contrast in the negative with

normal development, you would develop for N - 1 to end up with a

normal negative. I'm not sure of the answer to your question about

variable contrast paper. Brian