Speed Increasing Dev Question

Jed Freudenthal

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Right, any developer may be specified, but a certain developer has to be specified. For Ilford it can be ID 11, For Kodak D-76 for specific films. But, if another developer is more appropriate, another one can ce chosen. But it has to be chosen by the manufacturer. If a customer wants to use another developer for one or another reason he can do so.

Jed
 

Roger Hicks

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Dear Keith,

The ANSI formula appears (unsurprisingly) in many places. The reason it was dropped is that it flattered some emulsions, while making other look less good than they were. This, to me, makes more sense than trying to force everyone to jump through a single restrictive hoop imposed by a single developer formula. The manufacturers agreed -- rightly, in my view -- to standardize a great deal, but not on the 'wrong' developer for a particular film. What is the advantage of specifying anything other than density, contrast and (perhaps) agitation?

D76/ID11 is the de facto standard, but this does not affect my basic observation: true ISO speed (fixed density and contrast) can and does vary, by well over one stop, according to choice of developer.

If I understand Ilford aright, they use EIs instead of ISO because that's what people want and (athough they are far too polite to say so) because lamentably few people understand what ISO speed means anyway.

Cheers,

R.
 

Roger Hicks

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Dear Jed,

Another basic error -- and in effect, another shifting of ground.

The developer to be used to determine ISO speed does NOT have to be chosen by the manufacturer. The manufacturer is required to state (or more accurately, to disclose upon request) the developer he chose for the 'box' speed.

This does NOT affect the actual ISO in any specific developer. How could it? The actual ISO, as I have repeatedly stated, and as Ilford's and Kodak's own data sheets clearly imply, and as you are close to admitting yourself, varies with the developer.

In other words, if the manufacturer chose a different developer, there would be a different ISO speed. Ilford has freely given me their own ISO figures for HP5 Plus: almost 800 in Microphen, 250 or less in some fine-grain developers. They choose 400 as a middle-of-the-road speed in middle-of-the-road developers. Foma, on ther other hand, uses a speed increasing developer for Fomapan 200, which is almost identical in speed to HP4 Plus, nominal ISO 125. I have plotted the curves, and they are in any case reproduced in the spec sheets.

I hace suggested jokingly to Ilford that they repackage some of their Delta 100 as Delta 25, by the simple expedient of using a really speed-decreasing developer to determine the ISO speed. Pan F would be even easier to remarket as ISO 25. Given the terminal mistrust with which many B+W users treat ISO speeds (usually because they do not understand the ISO standard), many buyers would believe them, and indeed say, "Wow! This stuff is even a little faster than they say!" To their credit, the Ilford directors to whom I suggested this (most or all of whom have a background in research) were amused but declined to try the idea.

So are you now prepared to admit that ISO speeds vary with developer? If not, why not?

Cheers,

Roger
 

Keith Tapscott.

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Now that you`ve explained that bit about the ANSI developer yielding less than good results with otherwise very good films, it does make sense to provide data for processing the film in a well suited developer for that particular emulsion.
I do acknowledge that D-76/ID-11 are the one`s that other developers are judged by and that finer grain with slightly less speed (Microdol/Perceptol) or higher speed with slightly coarser grain (Microphen/Ilfotec DD) can be obtained or indeed if the tonality of another developer type provides a `look` that the photographer prefers.
 

haris


OK, now I am again at start...

Thank you for patience with me varjag, but I still don't get it. Can you, or anybody, tell example, real life photo situation where increasing speed with developer need (or wanted) to be done, why and how. What are situation in which photographer choose he/she need to develop film in speed increasing developer and not in "regular" developer...
 

David A. Goldfarb

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You're making it harder than it needs to be. You use a speed increasing developer when you need more speed.

Why would you need more film speed? Because you don't have enough light otherwise to take the photograph that you want. That means general low light photography or perhaps a situation where you want more DOF (smaller aperture) or a faster shutter speed than the lighting conditions allow.

For instance, I often shoot handheld with my 4x5" Linhof Technika. My fastest lens is a 135/3.5 Planar, and that's not always the right lens for the job, so I shoot a film like Tri-X and develop in Acufine to get an EI of 640.

Shooting medium format indoors with available light, I usually want as fast a shutter speed as I can get with lenses that are no faster than f:2.8. For this purpose I shoot Tri-X 400 and rate it at EI 800 by developing in Acufine.

Could I acheive this speed with D-76? After all they list those "push" times on the instruction sheet. Not really. Extending development time with D-76 will push up the highlights and give me something printable, and some people might even like that "pushed" look, but I'd rather have a normal contrast neg with a full range of tones, so I use a speed increasing developer.
 

Roger Hicks

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Dear Haris,

You need more speed for shorter shutter speeds or a smaller apertures. I kniw you know this but I'm just stating the obvious.

There are three ways to get more speed.

1 Buy a faster film. This costs more, and you may not have the time to do so.

2 Develop your film in a developer that gives a true speed increase (e.g. DD-X gives you 650-800 with your 'ISO 400' HP5 (which is ISO 400 in a non-speed-increasing developer.

3 Increase the development time of any film in any developer (this is 'pushing'). You will get more density but also more contrast, i.e. you are no longer working to ISO contrast and therefore speed.

Of course you can combine any of them. Start out with FP4 (ISO 125) in D-76. Develop in DD-X and you get almost ISO 250. Push two thirds of a stop (give it longer in the dev) and you have EI 400. Or push one stop in D-76 and you have EI 250...

Or buy HP5; use DD-X and get 650-800; push less than 1/2 stop, and you have EI 1000...

(Anchell and Troop maintain you can push further in a non-speed-increasing developer but this counters my own experience and the knowledge of every sensitometrist I have ever discussed it with).

An interesting aside is that a slower film in a speed increasing developer will almost always be finer grained than a faster film in a fine-grain developer, and may not be much slower, e.g FP4 in DD-X very close in true ISO speed to HP5 in Perceptol.

Hope this helps. As I said before, you might also care to read the free ISO module in the Photo School at www.rogerandfrances.com.

Cheers,

R.
 

haris


THANK YOU David and Roger!!!!!!!!

I thougt that in first place, but I was told what you David just described IS "pushing", and after that I was lost. Now it's clear. Finally...

Thanks again.
 

Roger Hicks

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haris said:
THANK YOU David and Roger!!!!!!!!

I thougt that in first place, but I was told what you David just described IS "pushing", and after that I was lost. Now it's clear. Finally...

Thanks again.
Click to expand...

Dear Haris,

You are more than welcome.

It is not uncommon in photography to THINK you understand something -- and indeed you DO understand it -- but someone then tells you something that makes you wonder if you really do. And then you find that they are the ones who are wrong, not you!

Cheers,

R
 

Soeren

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Are you able to get the Film development cookbook?
Here Anchell and Troop covers different types of films and developers hereunder some speedincreasing devs. It is quite basic and easy to understand thogh it does not cover this subject that thoroughly but its adequate.
Cheers
Søren
 

haris

Books..,

I ordered some books about 2 months ago and who knows will I get them. Fortunately I will pay them when/if I get them, so no harm... I also ordered that 2DVD issue about HCB through French cultural center here in Sarajevo, and who knows...

You know, because of not using CC, amazon and such are out of question for me, so for me is easier to buy new camera then new book

Will try...

Thanks and regards,

Haris
 
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