how can one develop a decent photograph at grade 1 or 2?

[Ed Sukach]

Reciprocity failure is due to time, not intensity.
I have never seen tables for compensation for reciprocity "failure" (change might be a more appropriate label) based on anything other than time.

I'll let Photo Engineer contiunue with this - if he wishes to do so. I'm still recovering from the "Diffraction" and "IR Focus Shift" discussions.

 

[Photo Engineer]

Ed;

Thanks. As I said in my last post though and the one before, it is due to time, but I guess no one wants to listen to us. On top of this, at an absolute time there is HIRF and LIRF inherent in the exposure giving the potential for distortion of the curve or tone scale whichever way you wish to call it.

BTW, this poor HIRF and LIRF are two more reasons why older films sometimes looked more pleasing than current films. One or the other or both of these types of RF were skewed from the other.

PE

 

[dancqu]

I have never seen tables for compensation for reciprocity
"failure" (change might be a more appropriate label) based
on anything other than time.

I think it has the strength of being a law; the law
of reciprocity. In equal measure as the level of light
is increased the exposure time is decreased. As light
levels fall in equal measure exposure times increase.
At very low levels of light The Law Fails.

I also have not seen tables other than those based
on time. It is though my understanding that any EV
value can be equated to some absolute level of
light intensity. Working backwards from those
EV values it should be possible to construct
tables based on light levels. Dan

 

[Ed Sukach]

I think it has the strength of being a law; the law
of reciprocity. In equal measure as the level of light
is increased the exposure time is decreased. As light
levels fall in equal measure exposure times increase.
At very low levels of light The Law Fails.

It only "fails" because of the extended TIME.

I also have not seen tables other than those based
on time. It is though my understanding that any EV
value can be equated to some absolute level of
light intensity. Working backwards from those
EV values it should be possible to construct
tables based on light levels. Dan

Doesn't it strike you that there may be a reason why talbes of "Reciprocity Compensation" based soley on intensity do NOT seem to exist? The ony significant factor is TIME - no matter what reason for the increased time.

Tell me - if you do construct such a table - based on EV values .. what information will it contain? At EV4, how much will the exposure need to be adjusted - as compared to EV10 - for any film? Will the compensation be done with changes in f/stops -- or shutter speeds? - or a combination of both?

 

[Photo Engineer]

I think it has the strength of being a law; the law
of reciprocity. In equal measure as the level of light
is increased the exposure time is decreased. As light
levels fall in equal measure exposure times increase.
At very low levels of light The Law Fails.

I also have not seen tables other than those based
on time. It is though my understanding that any EV
value can be equated to some absolute level of
light intensity. Working backwards from those
EV values it should be possible to construct
tables based on light levels. Dan

Dan;

The law fails at low levels and high levels that is why there is LIRF and HIRF.

PE

 

[nworth]

Let's separate film effects and print effects here. The only reasons for mushy or unsaturated blacks in the print are insufficient exposure of the print or insufficient development of the print. Given sufficient exposure and development, you should be able to get good blacks on grade 1 paper, but the print may still look dark or muddy if your negative contrast does not match the paper contrast.

Once upon a time, film manufacturers recommended development to a gamma of 0.65 for printing on grade 2 paper with a diffusion enlarger. Now the development recommendations produce a gamma of about 0.5, which needs about one contrast grade more. I don't know if the paper contrast grading system has changed to match this, but most of my negatives seem to print between 2-1/2 and 3-1/2. You can increase the negative contrast by increasing the negative development time, as in the zone system, with a possible compensating adjustment to exposure. But there are some compromises here, and you may have to experiment a little to get negatives you like.

 

[phritz phantom]

and the ending of the story is...
i finally printed a film at grade 1 (mostly). as recommended i tried ilford hp5 and developed it in xr-1. since there are no development times available for that combination and i don't know exactly atwhich film speed i exposed (i'm mainly doing night photography and most subjects aren't within the range of my meter, i think i exposed for 200 or even 100 asa), i took a guess and developed for 12 minutes.
out came astonishingly beautiful, but very dense negatives. my scanner couldn't handle them, but they are easily printable, apart from a few highlights.

 

[dancqu]

[QUOTES=Ed Sukach;414646]
"Doesn't it strike you that there may be a reason why
talbes of "Reciprocity Compensation" based soley on
intensity do NOT seem to exist?"

Tables. I had to think about that. I've come to the conclusion
that they would not be practical save for some laboratory purpose.
The actual on film intensity is dependent upon the scene, filtration,
and optics. What we use after those factors are taken into
account is the indicated exposue time. To that we
apply a correction factor.

Actually it's the films' doing. Their response to light becomes
very non-linear at very low light levels. T-Max and Acros
100 in particular are linear at very extended indicated
exposure times.


"Tell me - if you do construct such a table - based on EV values"

I'm not going to do that for reasons mentioned above. IIRC
enough information is available with the EV and it's definition
to calculate absolute values of light intensity. At least of
the scene being metered. Dan

 

[bjorke]

and the ending of the story is...
i finally printed a film at grade 1 (mostly). as recommended i tried ilford hp5 and developed it in xr-1. since there are no development times available for that combination and i don't know exactly atwhich film speed i exposed (i'm mainly doing night photography and most subjects aren't within the range of my meter, i think i exposed for 200 or even 100 asa), i took a guess and developed for 12 minutes.
out came astonishingly beautiful, but very dense negatives. my scanner couldn't handle them, but they are easily printable, apart from a few highlights.

This sounds not unlike the typically-described Ralph Gibson "dense neg" method (though I haven't seen your pics).

It seems that image contrast is one of those topics that is difficult to grasp for many people. I'm fascinated by the fact that in this thread different people seem to have a wide variety of different mental models to represent it to themselves, working either via theories of varying sorts or by rules of thumb like 'bigger print == higher grade." IMO all are correct in the sense that they lead those people to the results they expect.

I myself deal with contrast from math-based theories about domain sampling, but it doesn't really matter ultimately what method works for you -- as long as it does work.

I'm curious about the initial question, though. To my mind, the unanswered part of the question is: "a picture of what?" A wedding couple, black-suited groom and white-veiled bride? Or minute variations in the grain of a raw cliff face?

The overlapping relationships between contrast ranges in the scene, the film, and the paper (all of which can be controlled by the photographer, and all of which may have 'interesting' non-linear characteristics that can bedevil you or can be put to good use) are a sort of hierarchy. If you aim to make a picture on grade 1, you really need start by choosing the right subject for your picture before you press the shutter.

Your sample, btw, really screams 'split-tone print me!'

 

[Photo Engineer]

Bjorke;

Interestingly enough, your comment "all are correct" is right on and has rarely been discussed here.

You see, the eye integrates the entire tone scale (H&D curve) that is represented in the picture. Since the eye is linear (by definition) and the curve is an "S" that means that the toe and shoulder enter into the evaluation as well as the mid scale when we 'interpret' the picture.

Since the eye, being linear also has a slope of 1.0 in viewing an image (also by definition) then the integral of the slope means that the mid scale must be higer than 1.0 to make the picture look realistic.

But, everyone sees things just a bit differently in reality, and illumination plays a big part in this. Therefore if what you see pleases you, then it is correct.

The goal is to strike a balance to achieve something that pleases the majority. That is the hallmark of a good photographer.

PE

 

[gainer]

Reciprocity failure is due to time, not intensity.
I have never seen tables for compensation for reciprocity "failure" (change might be a more appropriate label) based on anything other than time.

I'll let Photo Engineer contiunue with this - if he wishes to do so. I'm still recovering from the "Diffraction" and "IR Focus Shift" discussions.

Yes, but the time is that calculated by the light meter's scale, which is dependent on light intensity at the film's surface and the speed of the film. The value that changes from film to film is the displacement of the curve of time to be added vs measured time. This curve is a straight line. The slope of this line is, for practical purposes, the same for all films I have plotted. To see this fact, one must plot the time to be added vs the calculated time on log-log paper, or the log of the time to be added vs the log of the measured time on ordinary graph paper.

The article I wrote for PT some time ago, "Reciprocal Trade Disagreement", is somewhere on www.unblingingeye.com if you want to see it. It is an analysis of Howard Bond's experimantal results from tests of 5 different films.

 

[Nicholas Lindan]

Interestingly enough, I have never seen this mentioned before on APUG, but at one time, most paper manufacturers suggested the use of grade 3 as the standard for enlarging due to the flare encountered when enlarging negatives.

And, they suggested going up in contrast grade as magnification increased.

Has anyone else heard of this from way back when?

I think Adams mentioned it in the bit about printing murals, I don't think he said why, though.

The stray light from the enlarger fogs the paper with the long exposure times when making large prints. The stray light lights up the whole room and as much hits the paper when making a mural as does when making a 5x7" print.
To keep the highlights clear mural prints are often underexposed, leading to mushy shadows, leading to the use of higher contrast paper. The result tends to be unsatisfactory.

If the murals are made in a really black room with no stray light there isn't a problem with contrast. Process cameras make huge negatives without the contrast going to pot over making small negatives. Same with large format cameras - the contrast remains the same when the negative gets bigger.

Enlargers are built arse backwards. The space between the lens and the paper should be the light-tight part. I think early enlargers were made this way, but then they were taken outside and aimed at the sun to make an
exposure. There is/was a Polaroid daylight enlarger made this way - daylab?

 

[Nicholas Lindan]

Reciprocity failure is due to time, not intensity. I have never seen tables for compensation for reciprocity "failure" (change might be a more appropriate label) based on anything other than time.

It is intensity that causes reciprocity failure. The exposure time is proportional to the intensity falling on the film and this is why time is used to calculate reciprocity failure, there being few people who figure the intensity of light reaching the film.

See Mees, "The Theory of the Photographic Process", the whole of Ch. 6 is dedicated to reciprocity, intermittency and other odd things.

 

[Ed Sukach]

Yes, but the time is that calculated by the light meter's scale, which is dependent on light intensity at the film's surface and the speed of the film. The value that changes from film to film is the displacement of the curve of time to be added vs measured time. This curve is a straight line. The slope of this line is, for practical purposes, the same for all films I have plotted. To see this fact, one must plot the time to be added vs the calculated time on log-log paper, or the log of the time to be added vs the log of the measured time on ordinary graph paper.

Inescapable logic! A "straight line on log-log (are you sure you don't mean "deci-log"?) paper. Uh .. yeah .. but in real time .. it isn't a straight line ... but a logarithmic curve.
Hopefully I won't have to revert to explaining logarithms here ...

The article I wrote for PT some time ago, "Reciprocal Trade Disagreement", is somewhere on www.unblingingeye.com if you want to see it. It is an analysis of Howard Bond's experimantal results from tests of 5 different films.

I know that the intensity of the light that reaches the film will determine the time of the exposure. I've known that for some .... Hah!! You thought you'd catch me admitting my age!. Well - a lot longer than I haven't known that.
It is when the TIME itself becomes inordinately long that reciprocity comes into play.

I tried that web address - unfortunately, it doesn't work. I have the Unblinking Eye bookmarked somewhere ... I'll give that a try - once I get some sleep.

My original question wasn't answered ... What correction would/ could be made in terms of EV? An example:

To the Hasselblad lenses ... EV9 is 1 second @ f/22; and 1/8 second @f/8; and 1/60 second @ f/2.8. My exposure meter tells me I need EV9. Is there any (at all - no matter how little) reciprocity error / effect between the EV9 given as 1 second @ f/22 and the EV9 as 1/60 second @ f/2.8? The total amount of light that reaches the film will be equal - only the time will be different.

If so, what correction in terms of EV would be appropriate?

 

[percepts]

it seems to me that to understand what recprocity is and how it works, you need to understand the physics of the reaction caused by the photons hitting the halides. Intensity is not a scientific term and is only confusing in this discussion. I suspect that the volume/rate at which the halides are being hit is what determines reciprocity.

Also consider the threshold of paper when being exposed to light. A certain length of exposure is required before anything happens.

Anyhow, to get back on track for the original poster and to restate my argument that part of the scene is in reciprocity and part is not:

Nightime scenes often have a high subject brightness range. i.e. the highlights are much brighter than the shadows when compared to a normal daylight scene. So if I meter a shadow as a zone III and then meter a highlight (Zone VIII) and find that it is 7 stops higher than my zone III i would need N-2 dev to bring it back to a zone VIII.

BUT my zone III requires 4 seconds exposure which is into reciprocity and so I give extra expsoure which pushes my Zone VIII further up the curve.

However, if I metered my zone VIII which was 7 stops higher than my zone III I find I only need 1 second exposure and doesn't require any adjustment for reciprocity. However it does means that my zone III may be blocked up.

because the subject brightness range is outside of the films normal range it is TRUE that part of the subject needs correction for reciprocity and part does not. How you go about dealing with that is open to debate. My own method is to expose for the highlights and and let the shadows go. After all it is a NIGHT shot. By doing it this way you will often get to use normal development and be able to print at grade 2. And the highlight separation is very good.
If you expose for the shadows and correct for reciprocity, you will need much development contraction to bring the highlights back which usually results in poor highlight separation and since there was never good separation in the shadows because it was night, you will still have poor or mushy shadows.

Photo engineer is wrong about reciprocity as it is applied to real world image making. He may be correct about the science but that was not the question.

 

[Photo Engineer]

Percepts;

What am I wrong about? Please explain.

HIRF and LIRF are facts. You describe a situation right in your post.

Lets take a bright lamp on a dark street. If you expose for the lamp, you may be using a good exposure for it centered in its best range, and no LIRF or HIRF will be apparent. The dark areas will be under exposed.

Expose for the dark areas, and you see LIRF effects and need to change the exposure time based on this. HIRF does not take place.

Use a high intensity strobe for the scene, and you may see HIRF effects due to the high intensity and short exposure.

In all it is intensity x time but time is the governing factor.

I may not have explained it clearly, but I don't think I'm wrong.

PE

 

[Thomas Bertilsson]

In my mind the simplest way to solve this problem would be developing the film by inspection. Expose generously to get the level of detail you want in the shadows, taking meter and reciprocity failure into account. Then use a dark green safelight for a couple of seconds to inspect the neg after a lot shorter time than your normal development. When, on the base side, you see the highlights coming through, you're approaching a negative developed with a full tonal scale (assuming you exposed for enough shadow detail).
This method is so easy for these situations, that in my opinion doing the math is just consuming time.

Edit: Reading the original post again it appears you use roll film. I didn't take that into consideration in my reply. It's more difficult to do development by inspecting the film with roll film than it is sheet film, but it can be done. Especially if all your exposures are similar. On a roll of 120, in a daylight tank, you could develop the film in your dark room. Since you need to look on the base side of the film, all you need to do is to take the film out of the tank and look on the outside of the film reel.
I would like to echo that if you consistently need to print on grade 4 paper then there is something in your process that needs adjusting.

My two cents,

- Thomas

 

[percepts]

Thomas,

DON'T forget the question was about night/concert photography. You must remember what is being photographed. Forcing good separation in shadows in a night time shot is fundamentally altering the scene before you and it will make it look unnatural as a night time shot since there will be very poor separation in the scene. IT IS NIGHT.

All I can say is to try it. Meter and expose for a zone VII or VIII and forget about the shadows and see what you get. You may be surprised at the result and how easy it is.

 

[Thomas Bertilsson]

Well, expose for whatever shadow densities you want then, but all the same, that's where you have to start.

- Thomas

 

[percepts]

Well, expose for whatever shadow densities you want then, but all the same, that's where you have to start.

- Thomas

Well actually no its not where I have to start. Pure dogma. Do yourself a favour and break a few rules.

 

[Thomas Bertilsson]

Whatever, man. You win, because I suck.

 

[percepts]

I didn't know I was in a competition.

 

[dancqu]

[QUOTES=Ed Sukach;416477]

"I know that the intensity of the light that
reaches the film will determine the time of the exposure."

I've no problem with that.

"It is when the TIME itself becomes
inordinately long that reciprocity comes into play."

Long indicated exposures do need a correction
factor applied.

"Is there any (at all - no matter how little) reciprocity
error / effect between the EV9 given as 1 second @ f/22
and the EV9 as 1/60 second @ f/2.8? The total amount of
light that reaches the film will be equal - only the
time will be different."

For most films a reciprocity correction will need be
made at 1 second. Exposure time AND THE LEVEL OF
ILLUMINATION at the film plane have changed. The
level at f/22 is 1/64 that at f/2.8.

"If so, what correction in terms of EV would be appropriate?"

I use the indicated exposure time then apply the correction
factor supplied with the film. I suppose a meter could be
programed to read out a corrected time. Dan

 

[Photo Engineer]

Dan;

HIRF takes place if the time is extremely short, as in very high intensity short duration strobe or the like.

PE

 

[gainer]

Inescapable logic! A "straight line on log-log (are you sure you don't mean "deci-log"?) paper. Uh .. yeah .. but in real time .. it isn't a straight line ... but a logarithmic curve.
Hopefully I won't have to revert to explaining logarithms here ...



I know that the intensity of the light that reaches the film will determine the time of the exposure. I've known that for some .... Hah!! You thought you'd catch me admitting my age!. Well - a lot longer than I haven't known that.
It is when the TIME itself becomes inordinately long that reciprocity comes into play.

I tried that web address - unfortunately, it doesn't work. I have the Unblinking Eye bookmarked somewhere ... I'll give that a try - once I get some sleep.]
ED,
www.unblinkingeye.com should work. The title of the article there is "LIRF is Lurking at Your F-Stop". If you search for "LIRF" on the unblinkineye site, you should find it.

The expression of LIRF correction as a straight line on log paper was determined by curve-fitting actual data, not as a logical theory. It makes no difference whether the log has the base 10 or 2 or 2.71828 the curve shape will be the same. The fact that the slope of the line, for practical use, is 1.62 for all films I had data for means that all you need to know about any given film is the time to be added when the measured time is 1 second, or for that matter, any other time. You can the draw a line through that point with a rise of 1.62 inches, centimeters, miles or kilometers and a unit run in corresponding units.

One thing you will notice about logarithms is that there is no zero. The number whose log is zero is not zero but minus infinity. The logarithm of 0 is 1.0 in any base.

When you use graph paper with a logarithmic scale, you are plotting time to be added against measured time, not their logarithms. It is not easy to get log-log paper these days, and if you cannot get it you can plot log vs log. The line will still be straight. I wrote a program to make my own log-log and semi-log graph papers. I can furnish a CD to set up that program on any version of Windows for the cost of reproduction and shipping.

[My original question wasn't answered ... What correction would/ could be made in terms of EV? An example:

To the Hasselblad lenses ... EV9 is 1 second @ f/22; and 1/8 second @f/8; and 1/60 second @ f/2.8. My exposure meter tells me I need EV9. Is there any (at all - no matter how little) reciprocity error / effect between the EV9 given as 1 second @ f/22 and the EV9 as 1/60 second @ f/2.8? The total amount of light that reaches the film will be equal - only the time will be different.

If so, what correction in terms of EV would be appropriate?

Any given EV can result in a wide range of f-stop and time combinations. There is no direct mathematical link between EV and LIRF. If you want a direct link between what your meter reads and the time to be added to the exposure time it calculates, you will have to compute the foot or meter candles of light that the meter is seeing, and will have to know the exposure time corresponding to some value of light intensity. Some meters have a table or scale that allows converting or reading directly the meter-candle value. It is not a direct, easily obtained conversion of EV to LIRF correction.