X-Rite 334 Sensitometer: Inspection and Analysis

[Alec246]

I've been lurking in this thread for a while and finally received my X-Rite 334. It was from a Pennsylvania branch of the EPA and pretty well-worn. From the stickers, it seems to have been used by a team monitoring radiation levels in the mid 00s.

Inside, it had the step wedge adhered with pretty scratched and degraded tape. I measured the wedge+diffuser on my densitometer, got some odd results, and opted to replace the step wedge with a brand new one from Stouffer. Looking forward to testing it further with the ISO method.


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.

It is nice to know if needed someday I can replace the original step wedge with a brand new one and have it all working perfectly!

About the template, I found it on Google. I have been trying to find the link for the author but have been unable to do so so far :/ I want to give credit to the creator.

I Will post here the version with a modification I made, the original had the X Axis reversed, so 0 was at the Right and went up to the left of the graph. I reversed it so the curve looks more standard to my eyes.

 

[Bill Burk]

Ah you used my graph paper.

As for zero on the right of the x-axis - that’s the density of the step wedge used in the sensitometer. It’s an “attenuation” scale. 0 being the clear step, gives you the highest density on the negative.

Thread 'Divided Attention'
https://www.photrio.com/forum/threads/divided-attention.127205/

WORKSHEETS & EXAMPLES
Recommended: Sensitometry Graph Paper
( http://beefalobill.com/imgs/sensitometry.pdf )

 

[reneboehmer]

I've been lurking in this thread for a while and finally received my X-Rite 334. It was from a Pennsylvania branch of the EPA and pretty well-worn. From the stickers, it seems to have been used by a team monitoring radiation levels in the mid 00s.

Inside, it had the step wedge adhered with pretty scratched and degraded tape. I measured the wedge+diffuser on my densitometer, got some odd results, and opted to replace the step wedge with a brand new one from Stouffer. Looking forward to testing it further with the ISO method.


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.

Hello Dan,
what do you think about the online tool? Does it work properly?
All the best! Rene

 

[Alec246]

Ah you used my graph paper.

As for zero on the right of the x-axis - that’s the density of the step wedge used in the sensitometer. It’s an “attenuation” scale. 0 being the clear step, gives you the highest density on the negative.

Thread 'Divided Attention'
https://www.photrio.com/forum/threads/divided-attention.127205/

WORKSHEETS & EXAMPLES
Recommended: Sensitometry Graph Paper
( http://beefalobill.com/imgs/sensitometry.pdf )

That's a great graph Bill, thanks for sharing that!

Oh I see. I will study the articles you sent on your link. I Have much more to learn about sensitometry, only started to scratch the surface here.

 

[Dan Rainer]

Hello Dan,
what do you think about the online tool? Does it work properly?
All the best! Rene

It works really well! I'm just starting down the sensitometry rabbit hole, but as far as I can tell every tool is right where it needs to be with lots of flexibility and customization.

I read "What Is Normal" and "The Delta X Criterion" right before finding your tool, so I was delighted to find something that put those concepts into practice in such a user-friendly, browser-based way.

My only criticism is that the glossary pop-up has too much transparency, making it a bit difficult to read. The words overlay onto the underlying text.

I'll be sure to give better feedback once I start consistently mapping H&D Curves and continue learning about sensitometry! Thanks for such a useful tool

 

[reneboehmer]

My only criticism is that the glossary pop-up has too much transparency, making it a bit difficult to read. The words overlay onto the underlying text.

Glad you like it so far! Make sure to always question the results. I just fixed the issue you were mentioning. Thank you! All the best.

 

[Alec246]

Glad you like it so far! Make sure to always question the results. I just fixed the issue you were mentioning. Thank you! All the best.

You are the developer of that tool? Great job it looks amazing!

I tried with the curve I posted earlier. I have one question for you

I entered the Density values I got for the values of Exposure Log between 0.60 and 3.00 in 0.15 Steps, but the tool ploted the curve with the first point at 0.15 Exposure. I Set the Gamma Exposure thingy for 0.6 and 3.0, am I doing something wrong?

 

[reneboehmer]

You are the developer of that tool? Great job it looks amazing!

I tried with the curve I posted earlier. I have one question for you

I entered the Density values I got for the values of Exposure Log between 0.60 and 3.00 in 0.15 Steps, but the tool ploted the curve with the first point at 0.15 Exposure. I Set the Gamma Exposure thingy for 0.6 and 3.0, am I doing something wrong?

Hello yes I made it.

When you use the X axis mode "Automatic" the program will assume a 21 step 0.15 step wedge.

Why does your test data start at 0.60? From what I can see, in your posted pictures you got a normal 21-step wedge sensitometer.

Its like this for any curve you want to plot, like on the physical paper you have to enter Y and X axis points. The Y axis points are your measured densities, and the X axis points are the given exposure. For relative exposure (if you don't know the exposure received by the film in luxs) you only enter the density steps from your step wedge. (If the x-axis mode in the software is on the automatic setting, the program will assume a .15 step 21 step wedge)

X data set should look like this: 0.15 0.30 0.45 0.60 .... and so on (.15 steps = 1/2 a stop)
Y data set could look like this: 0.29,0.29,0.29,0.29,0.29,0.30,0.33,0.37,0.43,0.50,0.60,0.69,0.79,0.90,1.03,1.15,1.26,1.36,1.47,1.59,1.75

Make sure you enter 21 density measurements.

I see on your negative that the first step is not 0.60 logD, but you mention you start with 0.60.

 

[reneboehmer]

This is what i get when i enter your data.

 

[reneboehmer]

Also don't forget that when using the sensitometer on Green setting your displayed contrast will be slightly to high and when used on blue it will be slightly too low. A actual Ci (under white light) of 0.60 might under the "green light" setting render as 0.65 and under the "blue light" setting render as 0.55. (Only very approxiamte suggetions)

 

[skahde]

That's very interesting, I wasn't aware of this effect and may have screwed my future tests! Big Thanks for That! Do you know the reason? Is it the spectral transparency of the step-wedge?

 

[Stephen Benskin]

That's very interesting, I wasn't aware of this effect and may have screwed my future tests! Big Thanks for That! Do you know the reason? Is it the spectral transparency of the step-wedge?

It's called the Gamma-Lambda Effect.

 

[skahde]

So, this looks like a non-linear response of the different sensitizing dyes? Very interesting, never heard about it so far. Again: Many thanks for the headsup and the explanation!

 

[reneboehmer]

Do you know the reason?

Silver Halide crystals are naturally only sensitive to blue and ultraviolet radiation, as you may know. Dyes are added to the emulsion to absorb green and red radiation, extending the films' sensitivity across the visible spectrum ("light"). When a dye molecule absorbs a photon of light (a specific lambda) it enters an "exited" sate. To create a latent image, this energy must be transferred to the silver halide crystal. The most accepted mechanism for this is "electron transfer"; the exited dye molecule injects an electron directly into the conduction band of the silver halide crystal. This electron is then free to move and combine with the silver ion to begin formation of a latent image speck, and it is therefore as if the crystal itself absorbed the energy. The efficiency of this process is not uniform across all wavelengths dyes can absorb. This variable efficiency is the cause of the lambda-gamma effect.

There are several factors for the efficiency problem, like the state of aggregation; dyes tend to clump together, quantum yield; Not every photon will result in a transfer, based on many physical properties that vary dynamically and competing de-exitation pathways; The dye molecule doesn't have to transfer its energy to the silver halide. It can lose its energy in different ways, that do not contribute to forming a latent image. (F.e.: reemitting the light as fluorescence, or simply losing it as heat.)

My sources for this information :
Carroll, B. H., Hubbard, D., & Kretschman, C. M. (1934). The Photographic Emulsion.
Stroebel, L., Compton, J., Current, I., & Zakia, R. (2000). Basic Photographic Materials and Processes.

 

[skahde]

I very much appreciate the explanation. Most of it has crossed my way at one time or another. What is striking in my view is the fact that quenching effects in the energy-transfer seem to play a lesser role when higher amounts of energy are thrown at them, as if the mechanism hast "to get its feet out of the swamp" so to say. I suppose the quenching-mechanisms run into some kind of saturation and the overspill is transferred with lowered loss-rate. In result the curve is held back at lower energy-levels and seems in relation intensified at higher levels which ends up as steeper curve in the final measurement.

Once again, understanding what is actually going on with respect to physics may in the end help to convey the artistic expression one is trying to put into his picture. Analogue Photography simply is a fascinating subject in all of its aspects!