Determining factor for factorial development

[larfe]

Hi APUG,

I just wanted to find out what can determine the factor for factorial development. I've used the method for a couple of prints yesterday and was stunned to see how much more tones I got out of the highlights compared to non factorial method.

I know there is a reference in Tim Rudman's book to this but I don't find it very helpful. I'm sure the factor itself can be used to control contrast as opposed to using a default factor for a fully developed print.

Any thoughts?

 

[Doremus Scudder]

A couple...

First, the fact that you're getting more tones in the highlights is coincidental. Certainly, whatever you're doing helped the highlights, but basically, it's the exposure and, secondarily, the development time that determines whether you see detail in the highlights. If you extended development significantly longer than you normally develop with your factor, then that is the same as adding a bit extra exposure to the paper. Also, you may have been underdeveloping before...

As for contrast control; don't get your hopes too high. Modern projection papers don't respond all that well to contrast control by changing the development time. As print development progresses, it reaches a point where the optimum (final) paper curve is reached. Extending development after this point just moves the entire curve, i.e., increases paper speed and acts just like adding a bit extra exposure (aside: I use this to fine-tune my print exposures; it's a lot easier to add 15 seconds of development time than to add small amounts of exposure). Sure, you can pull the paper before development reaches the optimum point and get a less-contrasty print. Some here (Ian Grant) has a method to control the exact tone of warm-tone prints using a sliding scale of exposure and development time as well, but I don't think it affects contrast that much.

The purpose of factorial development is to provide repeatability as the developer loses activity. During a session, you note how long it takes for a medium low tone to first emerge after the print is immersed in the developer. And, you note how long your development time for a well-developed print is. Divide the latter by the former to get your factor. Then, as times for emergence of your low tone increases due to developer exhaustion, you simply extend total developing time by multiplying the emergence time by your predetermined factor. The factor and the exact tonality you choose are somewhat arbitrary. Just choose a low value and make sure you're not underdeveloping to start with.

Apropos this latter: If you're developing fiber-base paper, times less than 2.5 minutes are risking underdevelopment. I like a three-minute standard, which I can then modify in small increments in either direction for fine adjustment.

Hope this helps,

Doremus

 

[AgX]

What does "factorial development" mean?

I can't find it in any of my textbooks. The term "factorial" as it is defined by dictionaries/encyclopediae does not make sense here either.

 

[Doremus Scudder]

I explained it in the next-to-last paragraph of my previous post...

But, to clarify. When developing a print you note the time it takes for a medium-dark value to first appear in the developing print. You divide this into your standard print-developing time (assuming it is adequately long enough) to arrive at a factor. Say it takes 30 seconds for your chosen tone to appear and your print time is 2'30". Your factor would then be 5. Later on, when developing the same print, or a print with similar low tones in it, the developer may not be as active. Say this time it takes 40 seconds for your chosen tone to emerge. You then apply the factor (hence, "factorial"), multiplying 40 X 5 to get 200 seconds or 3'20" total developing time. The idea is that the extended time compensates for the degree of exhaustion of the developer and that the resulting print will be identical to one developed in fresh developer for 2'30". This doesn't hold exactly, but is very close.

Ansel Adams explains it in more detail in his book, "The Print," which should be one of your textbooks if it isn't already!

Best,

Doremus

 

[larfe]

Indeed my guess is that I was under developing my prints

And, you note how long your development time for a well-developed print is.

How do you tell what is a well developed print?

 

[larfe]

Also the recommended factor is usually 6. Why 6?

 

[pdeeh]

How do you tell what is a well developed print?

presumably, it is a print with which you are satisfied ...

 

[larfe]

presumably, it is a print with which you are satisfied ...

Exactly, hardly a standard

 

[pdeeh]

to the contrary, the only standard that matters

 

[gone]

Wow. I just put the paper in the developer and develop it to completion. Never heard of this.

 

[Bill Burk]

Hi larfe,

I was reading an old book "Fundamentals of Photography" by Paul E. Boucher, and I didn't quite understand the simple formula when I first skimmed the pages while yakking with @peoplemerge ... so your question was already in my mind...

"The factorial system of development was first proposed by Alfred Watkins in 1893"...

He attributed different factors to different developer components: hydroquinone, 5; glycin (with carbonate of soda), 8; paramidophenol, 16; and metol, 30

For a developer that is 3 parts hydroquinone and 1 part metol...

The factors for each part: 5 + 5 + 5 + 30 divided by four parts = 45 / 4 which works out to a factor for that developer of 11 1/4

So.... that's the historical way to come up with a factor.

Doremus Scudder's way (where you start with an already known development time and divide that by the emergence time) is the way Ansel Adams taught it. It is probably more practical to work that way.

 

[markbau]

Factorial development is really just a technique to get consistent prints when doing multiple prints which takes into account temp variations and loss of developer activity. I think Adam's chapter on it was quite misleading. Extending development will, of course, give you a darker print, I'm not sure I would say it is a contrast control as I don't think extending development increases contrast in a print. Try it next time you print, expose 2 sheets identically , develop one sheet for 2 mins, then another for 3 mins. The second print will be darker, now adjust exposure to match the highlights and do a second 3 min development, you tell me if there is a contrast increase.

 

[Doremus Scudder]

A couple of things: First, there is an optimum development time for papers; the time at which the curve shape stabilizes and blacks have been fully developed. Too short developing times result in reduced contrast and less-dense blacks. Longer development times used to be recommended to increase contrast, but, as mentioned, modern papers mostly respond by simply speeding up (i.e., just like adding a bit extra exposure). So, there is a way to tell a "well-developed print." It is one that has developed long enough so that the end contrast has been reached and has good blacks.

Striving for D-max, as Michael points out, can lead to frustration. However, knowing how a print behaves while developing and watching for the developing to stabilize (or "complete" if you prefer) will prevent underdevelopment.

Factorial development is useful when developer temperature is fluctuating (doing essentially the same thing as the Zone VI compensating timer does) and for recognizing when the developer is starting to lose activity. I don't recommend trying to get good prints out of exhausted developer by extending development using factorial development; toss the developer and mix new.

Best,

Doremus