Find dev time without enlarger

[younghoon Kil]

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]

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:



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...




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]

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]

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]

Thank you folks for your detailed and kind explanations.
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]

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.




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]

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.



-------------------
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]

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]

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]

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.