Are we Kidding ourselves?

Barney

Barney

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Wayne
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By shooting EI at less than box?

It seems to me that we may be allowing more light to account for the deficiencies of the developers?

Do you, or have you taken into account the additional EI calculations to really let in more light?
 
Apologies.

If box speed is 400, for instance, and we shoot at Exposure Index of 200 then my assumption has been that I am letting in more light, If the developer I am using cannot maintain the rated Exposure Index of a film Is letting in more light by adjusting EI really letting in more light?
 
1. All developers are compromises, juggling between fine grain, maximum film speed, acutance.
2. Manufacturers developing times are accurate for their processing equipment (method of development, accurate temperature control), their accurate exposure times and their accurate apertures (or, more properly, light sources; lenses will loose some light due to reflection from air to glass surfaces, absorption from less than 100% transparent glass, and, in the case of some lens aberrations, more exposure than the stop predicts).
3. Film speeds are predicated on the developer (point 1) and developing times (point 2) and are fixed by the ISO standard.

From which
4. If you can't match all three point above exactly, the ISO standard speed won't apply.

Should you be sufficiently deviant to actually want more shadow detail than the standard would give you (speed is defined by that which gives a density of 0.1 above base + fog) and your processing gives a different contrast to that of the standard (which will depend on how you are making prints from the negative - diffuser enlarger, condenser enlarger, cold cathode head, scanner) then you may well find that the exposure needs to be adjusted.

We are not fooling ourselves by adjusting exposure to give the negative density we need for our prints; we are if we accept sub optimal results by following a rulebook which assumes methods and controls our own work flow doesn't - or can't - provide.
 
It is not really the deficiency of a specific developer that requires an Exposure Index less than box speed, it's just that the ISO/box speed is calculated using a specific developer, and other developers are ..... different ... not necessarily better or worse.

Stephen made a more comprehensive response whilst I was typing.
 
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Barney said:
Apologies.

If box speed is 400, for instance, and we shoot at Exposure Index of 200 then my assumption has been that I am letting in more light, If the developer I am using cannot maintain the rated Exposure Index of a film Is letting in more light by adjusting EI really letting in more light?
Click to expand...

In this instance, you are increasing the exposure by one stop. If you do this by opening up the aperture, you're letting in more light. If by changing the shutter speed, you're letting in the same amount of light for longer.
 
Thanks for that, as I suspected, its all my own fault and I need to better combine and understand my own output to the films and developers nuances, and thats before taking into account my old fauly equipment about which I have not a clue as to whether it functions as it should. Its all luck.
 
"Ah, now I sense the light" said the blind man, as he walked into the lampost - I should have known it would all be too esoteric for me - I think I'll stick with digital where I can make changes and see the results in real time and reverse them if they don't give the effect I think I want.
 
I used to regularly expose colour film at an EI a bit under box, and then get it lab-devved as for box. I thought the results gave a bit more saturation, so Portra wasn't quite so pastel, for example. I still do, sometimes. But then, I hate tripods and I'm old and trembly, so I often find myself setting the EI to box speed to give me longer exposures. I can't say I've noticed the difference!
 
ChrisR said:
I used to regularly expose colour film at an EI a bit under box
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That's colour negative film, to be clear. Do the same with slide film & you'd be right up the creek!

I think you need a consistent methodology, irrespective of your level of expertise. My knowledge of wet processing is nil, and I would send exposed films to a lab - and in that circumstance for mono or colour neg I might expose at box speed but meter off the shadows, or rate the film as a slower one and take an average meter reading. It seemed to work. The hinge is what & how (tonal) information is recorded on the film - which is what'll have to be translated into a positive image at some point later, by whatever method.

If you did what I just described, it could be a good start, but it relies on your intelligence about how to meter what's in front of the camera. But that's a basic of photography. Or used to be.
If the above is then lab or home developed as being for box speed, no push, no pull, you should be pretty good to go. But the next pitfall could be having a lab scan to digitise the image. They pile 'em through. Think about it. Remember automated colour 'lab prints'? And know the phrase 'lowest common denominator'?

My version in the current age where digitisation is likely to be wanted at some stage beyond the negative, is to do that bit, at least. myself.
 
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droj said:
That's colour negative film, to be clear. Do the same with slide film & you'd be right up the creek!

I think you need a consistent methodology, irrespective of your level of expertise. My knowledge of wet processing is nil, and I would send exposed films to a lab - and in that circumstance for mono or colour neg I might expose at box speed but meter off the shadows, or rate the film as a slower one and take an average meter reading. It seemed to work. The hinge is what & how (tonal) information is recorded on the film - which is what'll have to be translated into a positive image at some point later, by whatever method.

If you did what I just described, it could be a good start, but it relies on your intelligence about how to meter what's in front of the camera. But that's a basic of photography. Or used to be.
If the above is then lab or home developed as being for box speed, no push, no pull, you should be pretty good to go. But the next pitfall could be having a lab scan to digitise the image. They pile 'em through. Think about it. Remember automated colour 'lab prints'? And know the phrase 'lowest common denominator'?

My version in the current age where digitisation is likely to be wanted at some stage beyond the negative, is to do that bit, at least. yourself.
Click to expand...

I thought something similar Droj when I read Lees post, you just cannot be sure how many times that soup mix has been used and surely it will deteriorate over time and become contaminated with the numerous bits of film already dissolved in it. is one stop over exposure enough?
 
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Barney said:
I thought something similar Droj when I read Lees post, you just cannot be sure how many times that soup mix has been used and surely it will deteriorate over time and become contaminated with the numerous bits of film already dissolved in it. is one stop over exposure enough?
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WHOAH! Slow down! One stop o/x may be fine - but how do you achieve it? By how you meter, or how you rate the film? Don't do both at once!
 
droj said:
That's colour negative film, to be clear. Do the same with slide film & you'd be right up the creek!
Click to expand...
Yes, sorry not to be clear.

I was surprised to learn that badly stored expired Provia 100F should be used at box and can still look lovely!
 
Barney said:
I thought something similar Droj when I read Lees post, you just cannot be sure how many times that soup mix has been used and surely it will deteriorate over time and become contaminated with the numerous bits of film already dissolved in it. is one stop over exposure enough?
Click to expand...
If lab technicians know what they're doing, they'll be replenishing or replacing the chemistry to keep it constant. If they're not doing that, you really shouldn't trust them with your film.

Of course, such experise costs money and they either have to get a fair amount of throughput or charge a lot to provide such a service.
 
AndrewFlannigan said:
If lab technicians know what they're doing, they'll be replenishing or replacing the chemistry to keep it constant. If they're not doing that, you really shouldn't trust them with your film.

Of course, such experise costs money and they either have to get a fair amount of throughput or charge a lot to provide such a service.
Click to expand...
Yes when I worked in a shop that had a Fuji mini lab, control strips and required replenishment of chemistry was a regular task. I want to say a weekly event but as it was a long time ago and I was not directly involved in the lab I did not pay that much attention to what was going on.
 
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