Thank you for taking the time to explain.
Thanks to you, I learned a lot.
Thank you for taking the time to explain.
Thanks to you, I learned a lot.
Chamonix 45N-2, Chamonix 45H-1
What are the rest of the numbers? Tell how you ‘shot’ the original. Was Stouffer in contact with the film in the holder (yay) or did you tape original to a window and aim your camera at it (uh oh)?
+1Originally Posted by Bill Burk
And: the original question was how to develop the film. So he has to vary the development, e.g. in steps of -30%, -15%, +-0, +15% and +30%. Then he will learn some truths about development, too.
Another question: as I read, the Stouffer Transmission Projection (TP) Step Wedges http://www.stouffer.net/Photo.htm serve "in the enlarger to establish exposure and processing adjustments and to determine the speed and contrast of photographic papers." Are we talking about paper or negatives?
The original poster wanted find out "the right film speed" ... Then you have to sandwich the film and the Stouffer sheet - as Bill said - in a 4x5 film holder and expose the holder with constant and untextured light e.g. from an enlarger or the northern sky. Of course you will have to recalculate your densitometer readings with double base fogs (2 film bases)
But then the question of visualizing textured subjects in II, III, VII and VIII - this is crucial in a critic of correct exposure and development - will remain unaffected ... So, what's the benefit of this abstract (densito)metering with its numerous possibilities of error?
fotografie.ist ...
Daniel, Exposure is critical for texture in the shadows, so first we have to expose to record the shadows. Then we can develop more or less to reach desired density in the highlights.
We won't record much texture under Speed Point, if we develop more or less then the angle of the curve will change, but speed point won't move much. An speed loss/increase Developer would move a bit the speed point.
If using true Speed of the process then point is always at 3.3 stops underexposure from true ISO speed -/+0 metering, sure you have texture from this point, different films may have different toe so at -2.5 stops you may have slightly better or worse texture. Also we may have metering/exposure errors of even 1 stop...
Development time is critical for the highlights if the curve is more inclinated (because a long development time) then we may reach very high densities that won't be easy to print with an enlarger, but would be easier to adjust in hybrid processing.
So, when we meter a "zone" we always have to know where is speed point and where falls that zone in the curve.
Development time changes Contrast Index, CI, see this graph:
Here the plot shows the contrast index from development time for different developers (for TMX).
The Normal contrast index is 0.62. The meaning of this is that is you multiply exposure light by x10 (3.3 stops) then density will increase exactly 0.62D.
For this reason the test made by OP is good, if the contact copy of the stouffer increases 0.062D in a step then contrast and development time are Normal. Of course this is in the say 0.3D to 1.8D range, toe and shoulder are compressed and step density increase will be lower. It is 0.062D because the 0.1D steps in OP's wedge.
As you said we have two main factors, exposure and developement. A calibration tells what we have to do. Aslo we can find that with some try-error cycles. IMHO best is using of both ways.
+1
This is exactly what I said. He determined texture in the shadows, as he said: "finally I got the right film speed". Now he wants to determine the development "to reach desired density in the highlights", as you said.
IMHO he thinks that he will find out the correct development time by metering different densities of the Stouffer shades of gray. But he takes a photograph of the Stouffer card instead of sandwiching the card on a sheet of film, in a filmholder, and exposing it with constant light through the card, onto the photosensitive layer. That's what the card was made for, in a positive process, of course.
He uses a card that is made for the positive process. But it is not made to determine negative development. And he operates with a densitometer that is really tricky to use. E.g. his measurement are useless if he doesn't take account of the different densities of the film bases.
In German we say: "Wer misst, misst Mist" (perhaps: "Goofing it up by metering"?)
From this point of view, given the nature of the Stouffer card, I even doubt that he determined the correct speed of his film. - As long as one accepts that the OP takes photographs of his uneven illuminated positive process Stouffer card, diagrams are useless. We don't drive a nail into a wall by using Windows, Word and Excel.
Let's keep things simple and understandable.
If you want to determine exposure and if you want to photograph something: then you will have to photograph textured surface that you place in zone II-III, in different steps. Then you find out your true film speed.
If you want to determine development and if you want to photograph something: then you will have to place the textured surface in VII-VIII and develop a few photographs with different development times. Then you find out your "true" development time.
It's that easy. You don't need cards. You can meter densities, too, of course. To do this, you can position a grey card near by your textured surface.
fotografie.ist ...
Daniel, the thread title is "Find dev time without enlarger".
To determine the Normal development time with precision the way used by OP is optimal, because it removes the errors in the exposure or in the true film speed.
At the end you want to know the Normal development time for a developer/processing (T, agitation, etc). You later may use N-1 or N+3, of course.
Normal development is defined as delivering a 0.62 relationship between H exposure and Density. As the Stouffer ensures a known exposure progression in the contact copy (from one step to the next) then by measuring the density increases in the contact copy from one steps to next we know exacty what Contrast Index delivered that development time, and if it is under or over the Normal 0.62 CI. So we find the exact Normal development time.
Keeping things simple: Making contact copies of the stouffer is an optimal way to know the Normal development time.
In fact it is the common procedure used to determine the Normal developement that it will be used to calculate the true ISO Speed. See Beyond The Zone System Book.
Of course, you are right.
But we aren't helping the OP. As we see his procedures are full of errors because he didn't make contact copies. Or do I misunderstand something?
BTW. An enlarger is much more simple than a densitometer.
And I never mentioned an enlarger at all.
I pointed out that he has to make contact copies of the Stauffer card, if he wants to use this tool. As you said, too.
Of course you change the development later, to get a N+- development. In fact you will have to repeat your development tests for each N-+ step. "Later", as you said.
You say: "Keeping things simple: Making contact copies of the stouffer is an optimal way to know the Normal development time." Your right. Given the positive process.
I never read this "Beyond The Zone System" book. I read AA. Fischer-Piel et al. And I am quite satisfied with the traditional procedures. Why should I buy a machine to drive my nails into my walls. I have got a good hammer.
But I have got this question: does the "Beyond The Zone System" book propagate the Stouffer card for the negative process?
fotografie.ist ...
Yes of course, using a density wedge is the suitable way.
The density wedge can be of calibrated type. If it is not calibrated then density of each step has tight enough tolerances anyway.
In the contact copy you know the exact relative exposure each step had the compared to the others, or even the absolute exposures in Lux·second if metering with a lux meter the light that reaches the Stouffer wedge.
If you want to plot the curve without a wedge then you have to ensure the exposures for each point in the plot are exact (relative or absoulte), you may need a precise alternative for that. A calibrated wedge is very precise, and with a single exposure you can plot all the curve with precise H exposure references.
If you are interested in practical sensitometry I'd recommend you get a BTZS book, used is near for free. IMHO there is no need to understand well sensitometry to craft great images, but film/development/papers always had a lot of gossip, and a good understanding about practical sensitometry enlights what is gossip and what is worth.
Hello All,
just would like to add my two pence.
Basically I am using the BTZS approach without having an enlarger or densitometer.
I use my trusted V700 scanner as densitometer and convert the RGB values back to density values.
If you are interested, please have a look onto Marcel's homepage about how to calibrate your scanner.
http://www.marcelpatek.com/scan.html
To find the answer quickly search for "Dmax estimation for Epson Perfection 4990 Photo" He also provides and spreadsheet to simplify the process. Please find the link below:
http://www.marcelpatek.com/download/...uffer_Dmax.xls
Additionally I use the spreadsheet and information provided by Ralph Lambrecht to do my personal film test.
http://www.waybeyondmonochrome.com/W...Evaluation.pdf
http://www.waybeyondmonochrome.com/W...Evaluation.xls
Hope that helps.
Regards
Oliver
I shot the Stouffer 4x5-31 target in the manner described in this article "Use Your Eyes! - Zone System Testing Without a Densitometer".
I simply thought that by measuring the Stuffer 4x5-31 target with my X-Rite 341 transmission densitometer, I would know the appropriate development time.
I also thought that Enlarger would not be needed.
But there seems to be a more complicated world than I thought.
(In addition, I have just read that B&W densitometer is not suitable for Pyro negative.)
While there are many articles on EI test using Stuffer target and Enlarger, it is difficult to find an easy-to-understand and simple EI test using Stuffer target and Densitometer only.
Thank you again for your interest and advice.
Chamonix 45N-2, Chamonix 45H-1
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