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Thread: Film Speed and Development Test (Excel spreadsheet supplied)

1. I assumed that zone 3 is in the range of about 0,37 (the value 0,37 is also an average value of the black shirt).
For me its clear, all those tests with the step wedges dont come up with the reality. So i will check in reality.

My next steps are just photographing and see how I feel watching my negatives.
But as a start those labor-tests are great.

best michael

2. Michael,

Just a quick reminder - remember to make prints as you go through your testing. When testing using methods and targets (density values, contrast) in books like WBM, Adams etc. etc., it is easy to get carried away calibrating everything precisely to the recommendations in the book, only to later find out when you go to print the negatives are not really "right" for you. Printing your test negatives and images along the way will help you tweak everything to fit your personal requirements.

3. Originally Posted by Michael Hoth
I assumed that zone 3 is in the range of about 0,37 (the value 0,37 is also an average value of the black shirt).
For me its clear, all those tests with the step wedges dont come up with the reality.
There are just 2 specific points on the curve that can be very closely controlled by you------the speed point, or the point that will define the effective speed that is found (in the ZS, it is a short range of 0.9D to .11D at Zone I)------and, the upper density limit that defines your "normal" development target (for me, it's in the range of 1.25D to 1.35D at Zone VIII). IMO, it is somewhat, for lack of a better way of putting it, pointless to be concerned about a specific density between those points----those points that determine the shape of the curve between the two target points, are very much dependent on the film and development combination, just my opinion.

4. Originally Posted by CPorter
There are just 2 specific points on the curve that can be very closely controlled by you------the speed point, or the point that will define the effective speed that is found (in the ZS, it is a short range of 0.9D to .11D at Zone I)------and, the upper density limit that defines your "normal" development target (for me, it's in the range of 1.25D to 1.35D at Zone VIII). IMO, it is somewhat, for lack of a better way of putting it, pointless to be concerned about a specific density between those points----those points that determine the shape of the curve between the two target points, are very much dependent on the film and development combination, just my opinion.
I actually think there is a more important point for many of us, and I believe it can be reliably controlled, the midtone point.

As a matter of course it s really nice when the midtone point we choose in the scene carries through to the mid tone point we want in a print with our enlarger set "normally". This allows easy printing pegged to what is for many of us our most important subject matter.

For many of us as long as our shadows and highlights fall "appropriate to support our subject" and in the film's easily printable range, we're happy.

What I'm saying is that I can shoot and develop to control the density of whatever single point I choose, whatever point works in my system.

5. Originally Posted by markbarendt
I actually think there is a more important point for many of us, and I believe it can be reliably controlled, the midtone point.

As a matter of course it s really nice when the midtone point we choose in the scene carries through to the mid tone point we want in a print with our enlarger set "normally". This allows easy printing pegged to what is for many of us our most important subject matter.

For many of us as long as our shadows and highlights fall "appropriate to support our subject" and in the film's easily printable range, we're happy.

What I'm saying is that I can shoot and develop to control the density of whatever single point I choose, whatever point works in my system.
I don't think there should be any arbitrarily derived density to key the printing on. Since there is no direct correlation between a specific negative density and a print reflection density why apply restrictive conditions to the process when they are not required. From The Theory of the Photographic Process, "Because of variation in subject matter and in the geometry of scene lightling, the optimum printing times for negatives are not predicted with complete success by any known printing time formula or any known automatic method of measuring the negatives."

6. Couldn't agree more. Another reason why I don't like minimum time to maximum black (in addition to the inherent problems with that test), and other print time "formulas".

7. Originally Posted by Michael R 1974
Couldn't agree more. Another reason why I don't like minimum time to maximum black (in addition to the inherent problems with that test), and other print time "formulas".
Totally agree with you on that one especially when you consider how the fractional gradient / Delta-X Criterion works.

8. Originally Posted by Stephen Benskin
Since there is no direct correlation between a specific negative density and a print reflection density why apply restrictive conditions to the process when they are not required.
Because it makes darkroom work easier and faster.

If you were shooting a movie or studio portraits or 2000 shots documenting a family trip would you not want your exposures to be as consistent as possible to minimize your work in the darkroom?

Zoning only differs from my thought in the point it picks to peg.

This really isn't my idea either, it's root s in Dunn & Wakefield's exposure manual.

9. Originally Posted by markbarendt
Because it makes darkroom work easier and faster.

If you were shooting a movie or studio portraits or 2000 shots documenting a family trip would you not want your exposures to be as consistent as possible to minimize your work in the darkroom?

Zoning only differs from my thought in the point it picks to peg.

This really isn't my idea either, it's root s in Dunn & Wakefield's exposure manual.
Mark, this more a question of not taking things to the extreme. Where in Dunn?

10. I'm sorry for being off the current topic but I have a questions regarding film test based on WBM in general. I tried to read all threads about the subject but still a few aspect of the method are not clear for me.
I'm referring to the method described in the WBM 2nd edition pages 214 - 224 and pdf document + xls spreadsheet ( http://www.darkroomagic.com/DarkroomMagic/Darkroom.html Film test procedure)

1. Exposure
I'm using 31 steps stouffer transmission projection step wedge, size like 120 film

Photographing step wedge using window, light table or slide copier (I'm aware about flare issue etc)

What would be the best way to measure correct exposure? Cameras I'm using do not have built in light meter. Take a reading from diffused "light source" (window, light table, slide copier) without step wedge and use it as exposure? Should it be adjusted or use exact light meter reading? or maybe take a reading with step wedge in place - which part of the step wedge should be used to read exposure (120 size step wedge is quite small)?

2. Densitometer (how to read densities for development time tests and effective film speed test)

In pdf document I found on page 4:

"My densitometer has a calibration
button to ‘zero’ out the measurements,
because it does not have an internal light
source of known intensity for transmission
density readings. In other words, it
can be used with different light sources
and allows for relative and absolute density
measurements. If your equipment has a similar feature,
then take the first reading with nothing in the light path,
push the ‘zero’ button, and then, continue to take all the
measurements.
This will enable you to measure the ‘base+fog’
density of the test negatives. If you ‘zero’ the measurements
to a blank piece of the film before taking any readings,
then all base+fog densities are equalized, and you would
be unaware of any fog increase due to development time.

but on the same page there is a Fig. 3 (please see attached) where densities for test negatives starts from 0.02, 0.03 therefore (in my opinion) could not be measured with densitometer zero out with nothing in the light path.

Also on the page 4. (pdf) there is a Fig. 4 (attached) which shows D min = 0.17 - is it 0.17 above base + Fog? Should densitometer be zero out on base + Fog or with nothing in the light path to correctly read film speed test?

Should I zero out densitometer with nothing in the light path or on film base (in case of step wedge on step 1 ?) ?

thank you
Tomasz

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