No, I mean instead of CI's, have a graph that shows N times.
No, I mean instead of CI's, have a graph that shows N times.
Thank you so much!Can do! Will take me some time tho
Thank you so much!
Update:
- Added Zone System table
- Added a Ci to Dev. time plot
Small Update for Bill:Can you add visualizers? Overlays that can be enabled with a checkmark?
For example the CI (two-radius) overlay and Delta-X transparency.
Can you make it export to/import from csv or tsv so that when someone wants to share the data they can just click export and post the file here?
Yesterday, while working on my tonal reproduction tool, I had the idea to make an online plotter for anyone who wants to plot their curves quick and easy. With this free, online tool, you can just input the 21-Step tablet Density measurements you made. The Tool will assume 0,15 log H steps. It is meant to be used with relative testing, this means you don't know the (luxs) exposure intensity that was used to expose the different densities. You can assign one curve (the one you developed for box speed) to your reference and enter the speed. Based on this, my tool will calculate the relative speed for each curve. It also shows the contrast index or gamma of the curve. (Contrast index is similar to gamma but takes another way to calculate curve form). You can also enter ISO R or LER in a field with some tolerances, and my tool will show you what curve to use for which paper. I also included a Flare slider, which will add a haze over the data that is more active in the shadows. (This is done because Camera systems and Optics don't transfer scene illuminances without distorting them.) You can export all your data in a somewhat nice PDF. I am still working actively on my tools, so take everything with a grain of salt.
https://analogworkshops.at/plotter.html
This is the website. Feel free to have fun with it and test it. I would again be very happy with some feedback!
Hope this helps someone!
All the best! René
View attachment 405502
Why not both? A table with a dynamic developmental model that's based on entered variables would be helpful. I believe I saw a CI / Time curve which can also be used to extrapolate development times. You actually need both. The aim CI values are calculated for -1, N, +1, etc, and then the development time is determined using the CI / Time curve.
I work with .15 steps because i plan to introduce a total measurements option, meaning the user can input the X axis in luxs.You worked so rapidly I don't know if you still assume 0.15 steps.
It's trivial to calibrate and smooth the curves to the "actual" attenuation of the grayscale step wedge used to expose the test steps. All you have to do is read the densities.
I see you have implemented the curve that matches ASA for reference/speed determination. Have you already or will you consider adding a calibration curve for curve accuracy/smoothing?
Very impressive!
are there any future plans to turn this into an application or make it available as a spreadsheet?
I work with .15 steps because i plan to introduce a total measurements option, meaning the user can input the X axis in luxs.
Could you elaborate on the calibration curve part ?
Since I mentioned speed and curve calibration I should answer both...
Right or wrong, this is how I declare the luxs that hits the film plane of the sensitometer:
Measuring luxs directly at the test exposure plane is hard. But indirectly is easy. Set up the "sensitometer" to be as consistent as possible. when you "find" a curve that fits ASA parameters (1.3 run 0.8 rise from the point 0.1 above base+fog) then it's fair to deduce that the film has reached its rated speed (assuming fresh film with good speed reputation and developed in standard developer). You can pin the luxs on that specific curve. From that day forward, that one curve is the luxs reference. So even though I determined the exposure using TMY2, today I used the same sensitometer exposure for TMY2, 5222 and Panatomic-X.
I would submit that standard curve for every run.
The calibration of each step then, comes from the measured densities of the step wedge.
When you get a step wedge (e.g., Stouffer T2115), the steps are never exactly 0.15 apart. Instead, you can measure the actual densities and consider each step to be attenuation of the luxs that hit the step of the Stouffer scale. The calibrated T2115C is an exception, they cherry pick good ones and read them with NIST-traceable densitometer and write down the measured densities and many of those steps are 0.15
Same as with the sensitometer exposure, I would use the densities of the Stouffer scale steps in every run.
To complicate things, I add a neutral density across half the scale with higher density (lower exposures). Nominally 0.6 but measures differently, for example 0.56. So although nominally the scale covers 0.0 to 3.0 in 0.15 steps, it's really about 0.05 to 3.05 in roughly 0.15 steps (and I stretch it out closer to 3.6)
Yes , implement of calibration as Bill mentioned, would be nice
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