ISO 6 doesn't specify a developer. Manufacturers can use any developer and multiple developers if they wish. It does specify the developer needs to be listed.
If you're testing, you should use the developer you intend to use in practice.
Thank you for the clarification.
But wont this mean the reference for Ilford Delta 100 at 0.1 over base+fog will no longer match the value expected for using as calibration for the light output?
Edit:
Does this look ok? I set maximum Exposure Time, Mode 7. More than that would require me to exposure twice
Thank you very much for these numbers!
I assume this is only true when using the ISO Standard Kodak D-76 Developer? I currently use XTOL, but I can purchase D76 just for these calibration process.
...based on a practical evaluation of film speed and is not based on foot speed, as is the ISO standard.
My use of the seinsitometer is rather simple. I more or less ignore the absolute output and find the ISO of the film by in-camera exposure. That way I can be sure camera and lightmeter together deliver the result needed in a real-world setup.
The step-wedge in the sensitometer just tells me if I nailed the development.
That way I also do not need to worry about spectral output vs. sensitivity.
Your strip looks pretty good. Maybe consider a touch less exposure. The key is to have enough toe to work with, especially with extended development times.
Two things from the Ilford D100 datasheet. They list ID11 or DD-X for "Best Image Quality" so you might want to use that developer. However, they also indicate the exposure indexes listed in the PDF file are:
That is more or less exactly how I'm doing it right now. Minus four stops correction after measuring a uniform target with constantly distrusted and frequently crosschecked devices and measure the resulting density. The optimal density is always debatable within the lower decimals. But I still have to take the time to get my Macbeth TD904 up and running again.So you find your Film Speed like described by Ansel Adams, bracketing shooting Zone I Metering, and the frame where the exposure gives you 0.1 over b+f, that is what your film speed is set?
So it would be beneficial to have more toe samples, meaning more patches with lesser density?
So you find your Film Speed like described by Ansel Adams, bracketing shooting Zone I Metering, and the frame where the exposure gives you 0.1 over b+f, that is what your film speed is set?
Zone System testing uses a different method than a sensitometric approach using a step table and curves. It states the 0.10 fixed density is four stops below the metered exposure. This method will generally generate a 1/2 to 1 stop slower film speed than the box speed because the ISO speed point is 3 1/3 stops below the metered exposure point (Hg/Hm = 10). Zone System users end up rating their film one half to 1 stop slower than the box speed without any complaints. In fact, most have no idea they are using erroneous speeds because most didn't have a way to confirm their results
That is also my understanding from the Zone System, and I am also in the process of reading the books. Ansel Adams makes it quite clear, it is a tool to allow the artist to transform his vision into a final print, and there are scientific but also very practical steps.I'm just reading Adam's books again: The system gives you a tool to make this decisions reproducibly and defines a usable baseline, it is not scientific standard of some kind and was never intended as such. I uses the scientific basis of sensitometry and densitometry as its foundation but in application is was meant as a practical approach, regardless of what some may make out of it.
The ISO speed is a point of reference that is the same for all black and white films no matter the characteristics. It links the physical nature of the film using a limiting factor and associates it with the perception of quality. It's psychophysical. After that, it's up to the individual to determine what works for them. What the ISO speed gives you is the point to base the exposure that works for you. My point is that most personal "speed" testing is either conceptually incorrect and / or experimentally error prone leading to a false sense of accuracy. It's more a waste of time than a benefit. It's better to just base an EI on an working EI based from the ISO. A sensitometer can then used that value as a reference.My personal bias is ISO speed leaves little or no under exposure latitude. This is by definition; minimum exposure to produce an excellent print.
So it would be beneficial to have more toe samples, meaning more patches with lesser density?
If there were any under-exposure latitude to an ISO rating, then the speed would be under rated. So, I don't consider this something acceptable for use outside of a lab.
It's time-consuming and not always possible to split off a tangent without either or both the resulting threads becoming hard to follow.How about removing it from this thread and placing it in a new thread?
It's time-consuming and not always possible to split off a tangent without either or both the resulting threads becoming hard to follow.
That makes perfect sense now! My Densitometer hopefully arrives this week, and then I can properly check the DensitiesYou “Need” at least one sample patch to develop beneath 0.10 above base plus fog so that you can interpolate where the curve crosses 0.10 above base plus fog. Two or three steps would be nice, they make graphs show the shape of the toe better, which can help you form opinions.
Thats great to know!p.s. In Post #76 the exposure seems right-on. Those first two steps look like one may be beneath 0.1 above base plus fog
This is my first Characteristic Curve made using the X-Rite 334 Sensitometer. Ilford Delta 100 following XTOL Tables. Used the process described above to find the Light Output of the Exposure Mode 6 on the 334, which was used for this curve.
Alec, what template did you use for your curve? I've been using https://analogworkshops.at/plotter.html but I've also been searching for a good pen-and-paper option.This is my first Characteristic Curve made using the X-Rite 334 Sensitometer. Ilford Delta 100 following XTOL Tables. Used the process described above to find the Light Output of the Exposure Mode 6 on the 334, which was used for this curve.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?