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younghoon Kil
1-Mar-2019, 02:52
Hello,

I read several articles and then I shot Stuffer 4x5-31 target, measured with a Densitometer, and finally I got the right film speed.
And now I have to find a suitable development time, but I don't have enlarger.
I scan with a Hasselblad Flextight X1 and print to an Epson printer.
I would like to know if there is a way to find suitable development time without enlarger.

I seek your valuable advice.
I am sorry that my English is poor.

Thanks,

Pere Casals
1-Mar-2019, 04:33
The enlarger is absolutely unnecessary to make calibrations.

To determine Normal development time you only need to expose the Sttoufer contact copy in a way it delivers a scale of densities that have low densities close to base+fog from the most dense steps of the Stouffer.

You only need to measure the exposure amount in lux·second only if you want to know the true ISO Speed rating, or to know how to expose the film, but for what's development time the exposure units can be "arbitrary" like in the Ilford datasheets. But I'd like to measure the exposure amount for real units like in the Kodak datasheets.

So just expose several sheets like you did before "for the right film speed", but ensuring you have the very low densities in the contact copies. Then you develop the sheets with different times and then you plot the family of curves, you determine the contrast index for each curve and this says what curve/development time was the Normal one.

So (for development time) you don't need more gear (enlarger) but more knowledge: I'd recommend you get a Beyond The Zone System book, (used, very cheap) to understand well sensitometry and logarithms usage. to me it's worth learning all that, in some 8 hours you may have a deep and solid understanding about practical sensitometry.

________________________________________________________________________


Anyway with next (cheap) gear you may be able to make technically sound calibrations:

You may measure your exact exposure by metering light reaching the Stouffer with a ($15) lux meter and exposing for a certain time with the help of an electric timer.

You want an exposure time of around 1 second, a longer exposure may have LIRF (reciprocity f.) effects. A shorter exposure may not be accurate if you use a tungsten bulb because of heating transitories in the filament.


...so if anyway you want to measure exposure you may use any lamp throwing some 10 lux on the stouffer, use a lux meter (some $10 one) that has 0.1 LUX (or 0.01) precision to adjust your illumination source (distance/masking/etc) to get those 10 lux light intensity:

188232

Then you may use a $9 timer like this one that has 0.01s precision, you may change hour units by second units, in that case decimals will allow 0.01 second precision settings, adjust one second...

188231


For ISO 400 films instead 10 Lux and 1s you may want to expose 2 Lux and also 1 second.

Note that exposure is instensity multiplied by time, so 10 lux during 0.7 seconds is 7 Lux·Second. In the horizontal axis you plot the decimal Logarithm of the exposure, so Log 7 is 0.85H , note the "H" saying log was applied.

The exposure for each step is calculated from the exposure reaching the stouffer and the density of the step in the stouffer: step that has 1.0D density allows to pass 1/10 of the light to the film, so if exposure on the stouffer was 7 Lux·Second then 0.7 Lux·S reached the film in that step, so you exposure in H is Log 0.7 = -0.15.

You have to learn that in the Beyond the Zone System book, then you will have the powerful technical tools.



You can use your scanner as a densitometer, just scan 16bits/channel the contact copy alongside the Stouffer patron without any image enhancing feature. Then you can compare the contact copy with the stouffer to find what density are the gray levels, as the stouffer original has known densities for each step. It you have a calibrated Stouffer then you have the real values, if not you have aproximate values with known tolerance, which is good enough IMHO.

neil poulsen
1-Mar-2019, 09:00
I use an enlarger as part of my calibrations to determine normal development time. (Or, at least to check if my normal development works with current my paper of choice.)

I do my film speed test, which generally sets HP5 at 200 ASA. At that ASA, my normal development is that which gives me a Zone VIII of 1.35 on a densitometer. Using an enlarger, I find an enlarger development time at a set height and enlarging lens aperture that gives me maximum black. I then print a Zone VIII patch on the paper for that amount of time and determine if it's a Zone VIII that I like. If not, I make minor modifications the my normal development time until I get what I like as a Zone VIII. For example, when I began using Ilford Fiber Base Warmtone, it was using this enlarger based test that I originally decided on 1.35 for Zone VIII. (It gave the the best Zone VIII.)

This was based on my testing. But, it was reassuring when I eventually learned that 1.35 is close to what John Sexton uses as a Zone VIII. Keep in mind, that calibrations ideally are supposed to optimize the development process to obtain the best final print. So, an enlarger will ideally need to play a role in calibrations at some point.

The above works for me, because I use only one paper. But I also think that, 1.35 would be a good overall value for Zone VIII if one uses multiple papers.

So perhaps after all, if one accepts the 1.35 value for Zone VIII, one doesn't really need to involve an enlarger in film calibrations. But as I indicated initially, I involve an enlarger in calibrations as a check.

With all this said, it occurred to me some years ago, if my paper of choice were discontinued, I'd be stuck with my current negatives. Are Ansel Adams photos printed on the same papers that were available at the time that he exposed his negatives? I doubt it. Yet, they appear to print beautifully.

I do calibrations once in about three years time, if that. Once completed, calibrations can be relevant for a long period of time.

Daniel Casper Lohenstein
1-Mar-2019, 10:21
Hello,
I read several articles and then I shot Stuffer 4x5-31 target, measured with a Densitometer, and finally I got the right film speed.
And now I have to find a suitable development time, but I don't have enlarger.


Hello,

this is how I learned it (Peter Fischer-Piel book):

You have to determine the correct film speed, normally by placing a textured surface in I, II and III.

You wrote you've already made a comparison with your densitometer. I use contact prints. Thats fine.

I am sure you've found out that your true film speed is ca. 1/3-2/3 of the box speed ...

Now you can expose 5 sheets or strips of film with a textured surface placed in VII, VIII, IX, with the new true film speed.

Then you develop them, but differently.

You could start with the time given on the developers box, on what you subtract -20%.

This time is your provisional development time, eg. box says: 10min = 600sec, 600sec - 20% = 480sec = 8min provisional dev time.

Just remember: your true film speed is only ca. half the box speed, isn't it ...

You develop the 5 sheets /strips, each of them with a different time, eg. -30%, -15%, +-0%, +15%, +30% of the provisional dev time.

Then you can determine the correct densities for VII, VIII, IX.

E.g. with your densitometer. There will be a negative that fulfills your requirements.

Of course it's interesting to determine the standard dev time in relation to your print praxis.

This means that you have to print the sheets on paper (or scan them), e.g. as a contact print, or through an enlarger.

There is a standard print time that is the shortest exposure time that you need to get the blank film carrier black in your contact print.

This is the time you have to expose the whole paper.

Then you copy the negatives with their constant VII-VIII exposures and their different devolpments, all with the same standard print time.

You will be able to compare which negatives can be copied, what means that you can see the textured white as you want it.

The negative that shows you the whitest but still visibly textured white (in VII-VIII) will be the negative with the standard development time.

There are people who want to place textured surfaces in II and VIII. This is absolutely ok. I tend to compare the different sheets. Each lens/film/paper/developer/enlarger/etc-combination has its own characteristics.

Regards

younghoon Kil
2-Mar-2019, 03:42
Thank you folks for your detailed and kind explanations. :o
It helped me a lot.
And I will try various things based on your explanations.

I would like to ask you one more question.
I have a Stouffer TP4x5-31 target film. http://www.stouffer.net/Photo.htm
Is there a way to find the appropriate development time with this film and Transmission Densitometer?

Thanks,

Pere Casals
2-Mar-2019, 07:28
Is there a way to find the appropriate development time with this film and Transmission Densitometer?


Yes, this is straight !!!

When your development is Normal the density in the contact copy will have a certain density increase each step. Normal contrast index is 0.62, the meaning of this is that if you expose x10 more light then density will grow by 0.62D.

Your step table has 0.1D increments, so in 10 steps transmited light is reduced to 1/10. Then it's straight.

When your development is Normal each step in the contact copy will increase density by 0.062D, so in 10 steps density in the contact copy has to change by 0.62D, in 5 steps 0.31D.

> If the change is too high (over 0.062D per step) then develop less, this was a too contrasty development.

> If the change is too low (under 0.062D per step) then develop more, this was a too low contrast development.

Of course that proportionality (0.062D per step in the contact copy) is to work in the "central" region of the scale, say from 0.3D to 1.7D in the contact copy, outside this range you approach the film toe or shoulder where we may not have a proportionality.

See this graph, density increases by 0.8D in a 1.3H exposure increase, this is 10 powered to 1.3, so x20 more light increases density by 0.8D.

188264


The meaning of this is that a Normal development/contrast makes that two spots in the scene that have a 4.3 stops difference in the metering will have a density difference of 0.8D: that illuminated spot will have 0.8D more density than the other one.

Note that 0.8/1.3 in the graph is 0.62, the normal contrast.

Also note that we speak about Normal development, appropriate development may vary depending on what you have in the scene and on what you want.

_______________________

Often check my development without wasting a sheet. Just in an ordinary pictorial shot I write down the metering of two (easy to locate) spots that are 3.3 stops separated in the metering. If development is Normal then the densities in the negative will have a 0.62D difference.

younghoon Kil
2-Mar-2019, 10:03
Thanks again for detailed explanation of Pere Casals.
Thanks to your explanation, I have learned a lot.


I just measured(without zeroing) the ORIGINAL Stouffer TP4x5-31 target film with an OLD X-Rite 341 Transmission Densitometer.
-------------------
1=0.05, 2=0.13, 3=0.23, 4=0.33, 5=0.45, 6=0.57, 7=0.67, 8=0.78, 9=0.88, 10=0.99,
11=1.09, 12=1.19, 13=1.31, 14=1.41, 15=1.51, 16=1.62, 17=1.71, 18=1.78, 19=1.88, 20=1.99,
21=2.12, 22=2.21, 23=2.33, 24=2.42, 25=2.53, 26=2.63, 27=2.75, 28=2.83, 29=2.96, 30=3.07, 31=3.17
-------------------


Also I measured(without zeroing) the Arista EDU Ultra 100 4x5 negative developed with CineStill Df96(24C, 4 min).
This Stuffer TP4x5-31 target COPY(Arista EDU Ultra 100) looks normal on the naked eye.

188274

-------------------
31=0.09, 30=0.10, 29=0.11, 28=0.12, 27=0.14, 26=0.17, 25=0.20, 24=0.24, 23=0.30, 22=0.35, 21=0.40 ...
-------------------
But the increment of each step seems to be very low...

Pere Casals
2-Mar-2019, 15:50
This is nearly normal...
From step 31 to 24 you have the toe, this is not linear.
If you consider from stop 24 to 21 you have near Normal density increase for each step...

mrred
2-Mar-2019, 17:43
I was taught that a grey card (properly metered) should always show up as .7 + base fog. I have always used that as a guide.

Pere Casals
3-Mar-2019, 02:25
I was taught that a grey card (properly metered) should always show up as .7 + base fog. I have always used that as a guide.

Yes... Normal is 0.72D over base+fog for a spot metered -/+0, so 0.7D is a good aprox.

(0.72D is 0.62D over m point, and m point is 0.1D over base+fog, 0.62+0.1 = 0.72)

A grey card is not necessary, a gray building is also good. The grey card is necessary to calibrate with incident metering, but it isn't with reflective spot metering.

Your method ensures that development is Normal if you use a full speed developer.

It you use a developer that modifies the film speed then you have to expose the test shot with the right EI matching the true speed that developer provides.

IMHO your method is perfect for common situations if knowing the aprox. "true speed" (m speed point) of the process, but using an Stouffer (like OP) is a good way to start with advanced control techniques. With the Stouffer one may see the full tonal range in the negative, including toe and shoulder, depending on exposure.

younghoon Kil
5-Mar-2019, 10:41
Thank you for taking the time to explain.
Thanks to you, I learned a lot. :)

Bill Burk
5-Mar-2019, 20:59
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)?

Daniel Casper Lohenstein
6-Mar-2019, 00:58
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)?

+1

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?

Pere Casals
6-Mar-2019, 01:44
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?


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.

188473

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:

188474

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.

Daniel Casper Lohenstein
6-Mar-2019, 02:04
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.

+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.

Pere Casals
6-Mar-2019, 02:40
Let's keep things simple and understandable.

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.

Daniel Casper Lohenstein
6-Mar-2019, 02:55
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 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?

Pere Casals
6-Mar-2019, 03:59
does the "Beyond The Zone System" book propagate the Stouffer card for the negative process?

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.

blnoli
6-Mar-2019, 06:38
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/SF_stouffer_Dmax.xls

Additionally I use the spreadsheet and information provided by Ralph Lambrecht to do my personal film test.
http://www.waybeyondmonochrome.com/WBM/Library_files/FilmTestEvaluation.pdf
http://www.waybeyondmonochrome.com/WBM/Library_files/FilmTestEvaluation.xls

Hope that helps.
Regards
Oliver

younghoon Kil
6-Mar-2019, 11:54
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)?


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. :rolleyes:

Thank you again for your interest and advice. :o


188494

188495

188496

Daniel Casper Lohenstein
6-Mar-2019, 12:41
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.


Well, it seems that you have done it right, as far as I can see, reading the Wainwright PDF. Please excuse me, my words were too aggressive.

You sandwiched your sheet of film and your Stouffer card. That's the right procedure.

Then you developed your film, "for what I think will be the 'normal' development time – the exact time is not critical at this point", because in the beginning your examine the 0 zone, evaluating the exposure. This is correct, too.

You have evaluated the exposure. This is good.

Now you have the highlights, the areas numbered from 1 to 7. Which of these areas corresponds to zone VII, VIII and IX? Apparently "each step represents a half-stop change in exposure", as Paul Wainwright writes. Now it's easy: you will have to measure the density in area 7, 6 and 5 to get zone VII, VII 1/2 and VIII. Pere Casals delivered the density values, so you can meter yourself, now.

Whereas Wainwright drives by sight: "Are there significant non-white steps above Zone VIII (for example, steps 1 through 4)?" Voilà, this is what I mentioned when talking about the structured subject: you can examine whether structured textures are visible or not, in the area itself. Wainwright adjusts his development time about +-20%, I prefer +-30% in 15% steps.

1. I think Wainwrights procedure is quite good. Nevertheless I would say that you would have to take account of the duplicated base fogs of the sheet film and the Stouffer Card, perhaps this works like a pre-flash: it mainly affects metering in area 21 and 20.

2. But I also think that his procedure is a little bit abstract. There should be a textured part in each area, as well a an untextured part for metering. This would make visual inspection easier.

3. And a third remark: Wainwright does not only use no enlarger. He does not even use a densitometer.

Regards, "Gut Licht!"

Bill Burk
7-Mar-2019, 09:10
I shot the Stouffer 4x5-31 target in the manner described in this article "Use Your Eyes! - Zone System Testing Without a Densitometer".

OK. Negative sandwich, yay

What are the numbers, for your three films, for steps 1-31

You have everything you need. All you need now is help interpreting the graphs. With the numbers I can graph it my way which will help me see what you got.

Don't worry that your negatives look flat (less gray difference between each step than the original). That's intentional. It should be about half. (You should see similar differences every two steps in your negative as there are differences each step of the original.

Don't worry about the difference between Pyro and normal developers (at least for now). There's a 'significant' difference (mostly towards the greater densities) but it's a difference best measured by results.

younghoon Kil
7-Mar-2019, 09:51
First of all, thank you again for all the comments.
Thanks to your attention and explanation, I was able to learn more than before.



OK. Negative sandwich, yay

What are the numbers, for your three films, for steps 1-31

You have everything you need. All you need now is help interpreting the graphs. With the numbers I can graph it my way which will help me see what you got.


[Stouffer 4x5-31 target and X-Rite 341 transmission densitometer]
[20180309: Arista EDU Ultra 100 4x5 @ ISO 64, PMK Pyro, 21C, 10 min]
0 0.08
1 0.09
2 0.14
3 0.26
4 0.46
5 0.62
6 0.89
7 1.09
8 1.21
9 1.31
10 1.38

[20190226: Arista EDU Ultra 100 4x5 @ ISO 50, Df96, 24C, 4 min]
0 0.09
1 0.11
2 0.17
3 0.3
4 0.47
5 0.62
6 0.83
7 0.99
8 1.1
9 1.16
10 1.18

[20190306: Arista EDU Ultra 100 4x5 @ ISO 50, PMK Pyro, 21C, 13 min]
0 0.12
1 0.15
2 0.27
3 0.47
4 0.73
5 0.96
6 1.25
7 1.51
8 1.68
9 1.82
10 1.9

[20190307: Arista EDU Ultra 100 4x5 @ ISO 64, PMK Pyro, 21C, 12 min]
0 0.11
1 0.14
2 0.22
3 0.39
4 0.66
5 0.89
6 1.15
7 1.38
8 1.54
9 1.71
10 1.82

[20190303: Kodak T-Max 400 4x5 @ ISO 125, PMK Pyro, 20C, 13 min]
0 0.43
1 0.46
2 0.55
3 0.68
4 0.83
5 0.95
6 1.12
7 1.31
8 1.51
9 1.75
10 1.94

[20180301: Ilford HP5+ 400 @ ISO 250, PMK Pyro, 20C, 12 min]
0 0.23
1 0.25
2 0.32
3 0.42
4 0.54
5 0.62
6 0.76
7 0.91
8 1.04
9 1.17
10 1.26

Bill Burk
7-Mar-2019, 09:58
Were you being brief? Or are you unable to read steps 11-31?

younghoon Kil
7-Mar-2019, 10:04
Oh, I was mistaken.
I'll measure it again and post it.
(I measured only 11 steps from Zone 0 to 10.)

younghoon Kil
7-Mar-2019, 10:26
[20190307: Arista EDU Ultra 100 4x5 @ ISO 64, PMK Pyro, 21C, 12 min]
1 1.82
2 1.80
3 1.76
4 1.72
5 1.67
6 1.62
7 1.57
8 1.50
9 1.45
10 1.38
11 1.30
12 1.25
13 1.15
14 1.08
15 0.99
16 0.88
17 0.81
18 0.75
19 0.66
20 0.55
21 0.45
22 0.38
23 0.31
24 0.26
25 0.21
26 0.18
27 0.15
28 0.13
29 0.12
30 0.11
31 0.11

p.s. I just measured it again. (Now it's 2:30 in the morning. :D )

younghoon Kil
7-Mar-2019, 10:43
[20190303: Kodak T-Max 400 @ ISO 125, PMK Pyro, 20C, 13 min]
1 1.88
2 1.82
3 1.75
4 1.70
5 1.62
6 1.56
7 1.48
8 1.41
9 1.35
10 1.28
11 1.22
12 1.17
13 1.10
14 1.04
15 0.99
16 0.93
17 0.89
18 0.86
19 0.81
20 0.75
21 0.70
22 0.67
23 0.62
24 0.58
25 0.54
26 0.51
27 0.47
28 0.45
29 0.43
30 0.42
31 0.42

younghoon Kil
7-Mar-2019, 10:55
[20180309: Arista EDU Ultra 100 4x5 @ ISO 64, PMK Pyro, 21C, 10 min]
1 1.42
2 1.40
3 1.37
4 1.35
5 1.32
6 1.29
7 1.25
8 1.22
9 1.18
10 1.13
11 1.07
12 1.03
13 0.94
14 0.86
15 0.76
16 0.66
17 0.60
18 0.55
19 0.49
20 0.41
21 0.34
22 0.29
23 0.23
24 0.19
25 0.15
26 0.13
27 0.11
28 0.10
29 0.09
30 0.08
31 0.08

younghoon Kil
7-Mar-2019, 11:09
[20190226: Arista 100 @ ISO 50, Df96, 24C, 4 min]
1 1.16
2 1.14
3 1.13
4 1.12
5 1.11
6 1.08
7 1.05
8 1.02
9 0.99
10 0.95
11 0.89
12 0.85
13 0.76
14 0.71
15 0.63
16 0.60
17 0.55
18 0.52
19 0.46
20 0.40
21 0.34
22 0.29
23 0.23
24 0.19
25 0.16
26 0.14
27 0.12
28 0.11
29 0.09
30 0.09
31 0.09

Bill Burk
7-Mar-2019, 19:08
Very cool thanks.

Bill Burk
7-Mar-2019, 23:53
188541

Here’s a graph of EDU 100 in PMK Pyro.

I subtracted B+F and drew green vertical lines to match densities of the Stouffer scale.

Your 10 minutes is just a tad high but meets ASA.

I sketched a quick Time / CI chart from the two data points.

Now all you have to do to find development time is decide what CI (Kodak Contrast Index) you want to develop the film to.

Pere Casals
8-Mar-2019, 08:01
Now all you have to do to find development time is decide what CI (Kodak Contrast Index) you want to develop the film to.

This is !!

younghoon Kil
8-Mar-2019, 11:28
To be honest, I'd like to ask you more about why 10 minutes meet the ASA, how did you get two data points, and which CI should I choose.
But I think that's a shameless question.
I think I should learn from the basics.
Thank you once again for everything you’ve done.

Bill Burk
8-Mar-2019, 15:33
The dashed triangle I drew are the ASA parameters. Your 10 minute curve is the one closest to meeting the tip of the triangle on the right. It just touches the top bar of tolerance. So 10 minutes is almost too much time.

The two points are the time vs contrast for 10 and 12 minutes. If you want a contrast in between you can pick it off the chart. For example if you want 0.65 (say N+1) you might develop for 10:45 in PMK Pyro.

If you do more tests at different development times you can get more points for the time - contrast chart and it will be more accurate.

For which CI you should choose, you will need to buy my book ( just kidding it’s free).... look at the charts on pages 10 and 11


http://beefalobill.com/imgs/20150812%20CallingYourShot-DividedAttention.pdf

Bill Burk
9-Mar-2019, 22:26
Here are your other two curves. I can’t say much except they are relatively underdeveloped.
But 0.5 is a “fine choice” if you consider printing with grade 3 as a target for normal subject luminance range. (It’s approximately N-1 in Zone System terms where the traditional aim is grade 2.)

I know you aren’t “printing” in the traditional sense but I consider the traditional aims to be still relevant (just in case someone wants to print your negatives one day) and the jargon helps to describe where you are and where you want to be.

Development to 0.6 contrast is a test standard for ASA speed, but in practice practically everyone “dials it back a notch” when doing their own development.



188622

188623

younghoon Kil
10-Mar-2019, 07:26
I have just started developing black and white film, but I'm getting a bit better negatives by little by little.
But I wanted to get a uniform and predictable result, so I was asked a few questions.

Thanks again for taking the time to explain.
Thank you very much!!


[20190309: Arista EDU Ultra 100 4x5 @ ISO 64, PMK Pyro, 21C, 9 min]
0.1
0.11
0.11
0.12
0.14
0.16
0.19
0.23
0.27
0.33
0.38
0.46
0.53
0.59
0.63
0.67
0.79
0.89
0.97
1.08
1.15
1.22
1.29
1.33
1.39
1.44
1.48
1.53
1.56
1.58
1.62

Bill Burk
10-Mar-2019, 09:13
188632

Your new curve falls between the first two. Either it is an outlier, or a new point for the time/CI chart.

I mark my own time-CI charts with these “scatter points”. Eventually a pattern will emerge and you will see the times you made a mistake and when it was right. Nothing ever really goes perfectly by plan, but it’s aiming and checking where you hit that helps you make “constant quality negatives”.

Chuck Pere
11-Mar-2019, 06:09
Something fundamental I don't understand. If you're scanning the film wouldn't you just develop the film to match the scanner density range? The density range should be part of the scanner specifications.

Bill Burk
11-Mar-2019, 16:58
Even if you do produce film for scanning, you will want to produce a negative with characteristics of quality.

Scanners have high Dmax in order to handle slides.

But most excellent negatives have relatively low density range. (Compared to slides I mean).

A contrast index (CI) 0.62 is on the high side of what most people do these days.

I don’t know the ideal for scanning, you would have to ask someone who does this, but I imagine it’s between CI 0.62 and CI 0.50

That holds down grain, maintains resolution and holds a host of other good qualities.

younghoon Kil
14-Mar-2019, 08:43
Thank you again for your sincere explanation.
I decided to start with the basics.
For example, I will look for the proper EI number again, and I will try to find a suitable development time by creating a contact proof.
I hope to learn more from these experiences.
Thank you.

p.s. So I am making a DIY contact printing box.(thicker board, multigrade filter, vc paper, contact print frame..) I think I might use the "Aputure Amaran AL-F7 On-Camera Variable Color LED Light" as a light source.

https://www.bhphotovideo.com/c/product/1400467-REG/aputure_amaran_al_f7_on_camera_led.html

Bill Burk
14-Mar-2019, 17:40
Wait. Don’t do that. All your development times were fine here. All your film achieved it’s rated speed.

Consider the rated speed of film to be correct for determining exposure for all the example processes you graphed here.

Now you are free to “index” to the film speed to meet your favorite look. I suggest exposing as if film was 2/3 stop slower, not because I think the film is slower, but because greater exposure assures me of having adequate exposure.

Bill Burk
14-Mar-2019, 18:01
I also want you to consider locking your “sensitometry” exposures to a couple choices. For example you were testing films with speeds of 400 and 100 but your exposures were varied. Don’t vary them. You will be able to read relative film speed off the graphs and it will be more apparent if you see the shift left for more sensitive film and right for slower film.

The reason to have a “fast film” and “slow film” setup is so the curve doesn’t fall off the edge of the paper.

Pere Casals
15-Mar-2019, 04:49
I also want you to consider locking your “sensitometry” exposures to a couple choices. For example you were testing films with speeds of 400 and 100 but your exposures were varied. Don’t vary them. You will be able to read relative film speed off the graphs and it will be more apparent if you see the shift left for more sensitive film and right for slower film.
The reason to have a “fast film” and “slow film” setup is so the curve doesn’t fall off the edge of the paper.

Bill, 3.0D wedge contains 10 stops, so we evaluate film response across 10 stops range. Same exposure for 400 and 100 leaves 8 stops for the 400 film if exposure is well adjusted to contain the 100 film toe. 8 stops range is a bit narrow range if wanting to explore well the 400 film shoulder with same exposure. A 4.0D wedge would allow it better.

Your proposition is a good choice, but let me propose an alternative: Just with a cheap ($20) lux meter we can adjust light intensity, so we have absolute units to plot each curve in the right place. Another way it would be to vary exposure time to the 1/4 for the 400 film, and then shifting the curve acordingly.

Time change it could be done if not using a filament lamp, but a CRI 98 LED lamp. The tungsten filament imposes a some 1 second exposure, because if longer then we have LIRF in the dense steps, and in shorter then we have inaccuracy from filament heating transitories.

My view is that a cheap lux-meter is a good gear addition, once we take the calibration effort... having the absolute exposure units is nice

Bill Burk
15-Mar-2019, 15:18
Yup 10 stops are covered and the same light that gives you a good graph on 100 will get just the upper part of the curve for 400. So a couple major light intensity differences are good.

But I always say the light can be arbitrary as long as it’s consistent. The graphs will reveal the amount of light that hit the film.

Bill Burk
15-Mar-2019, 21:55
The major point I was making about having two exposure setups for sensitometry instead of moving exposure about, is mostly for consistency and so you can learn to see the curves moving left and right. If you try to adjust exposure before you make each sensitometry test, you might get confused about what is happening.

So if the film is 80 or 64, you can use the same setup as for 100... if it's 320 or 200 use the same setup as for 400. As Pere said there's 10 stops in the step wedges we traditionally use. You really only need to land 7 or 8 stops of curve information to make a good graph. I'm only disappointed when my 400 speed film is overexposed by 2 stops and it makes the last reading above 0.10. (So I throw a 2-stop ND filter in the mix a lot of the time).

Anyway, younghoon has a good setup. I think it's daylight by camera shutter with adjustments for different speeds. That lends itself to either approach... you can try to hit the sweet spot of the curve every time. But I'm just saying don't. Instead choose the same f/stop and shutter speed where possible, picking one or two combinations as your favorites. Keep same shutter and change f/stop. Then the possibility that 1/125 and 1/500 are not exactly two stops apart won't mess up your tests (compared to when you using 1/125 all the time with f/8 and f/16). Let the curves move around a bit just so they don't fall off the paper or above 0.10

younghoon Kil
16-Mar-2019, 10:25
Thankfully you kindly and aggressively explained it, but I did not understand it well.
So I am very sorry for you.
That's why I'm trying to learn from the basics.
And I'm reading your posts again and again.

I have Stuffer 4x5-31 Step Wedge, X-Rite 341 Transmission Densitometer, Sekonic L-858D Light Meter and Sekonic Exposure Profile Target II.
So if I continue studying and doing various exercises, I think I can understand it.
Thank you very much.

Bill Burk
18-Mar-2019, 21:24
Once I shot (a roll of 35mm) a Step Wedge, my black and white dog in the outdoors, and a Sekonic Exposure Profile target on the same roll of film.

Since it's developed at one time, the graph of the step wedge, and the densities I read from different parts of my dog, and densities of different patches of the exposure profile target can all be graphed on the same chart page.

Here's what the graph looks like. I learned a lot from this test. You could try something just like it.

http://beefalobill.com/imgs/tmxaim.jpg