AA's Value I density targets

[Doremus Scudder]

Doremus and others, per meters. Flare is easily controlled. You can put a rubber lens shade on a Pentax spotmeter just like a camera lens. It's an odd but available size, 40.5mm if I recall correctly.

Drew,

Lens hoods (even toilet-paper tubes attached to the meter that block everything outside the meter's field of view) don't seem to do the job for me.

With my Pentax digital spot meters, the reading area is just a small fraction of the entire field of view, so there's still a lot of light that can be bouncing around inside the meter that isn't being directed to the small circular area being metered.

I notice a difference metering shadow values when they are surrounded by much brighter objects. In the case of, say, reading under the eaves of a white clapboard building from a distance, I can get the shaded area to just fill the metering circle, but the glaring white walls are still there in the meter's field of view. I'll get a reading of X for that shadow from that distance with that much bright stuff in the field of view. Now, if I walk up closer so that the entire field of view of the meter is filled with the shaded area, I'll get a significantly lower reading; maybe one or two EV lower, than the first reading. The illumination of that shaded area hasn't changed any, so it has to be flare in the meter that's causing the discrepancy. When I have those situations and I can't walk closer and meter the shadow without bright things in the field of view, I'll figure that my shadow-value reading is high and add some exposure, usually just a guesstimate based on how bright and large the surrounding bright areas are.

Try the same experiment with your spot meters; I'll bet you see similar flare.

Best,

Doremus

 

[DREW WILEY]

Well, it takes experience just like with any other metering method. And given the scenario you describe, with just a small shadow in the midst of otherwise brightness, I seek out larger areas of the same depth of shadow somewhere nearby, at an analogous angle of view. And having done so thousands of times before, it all becomes easy to interpolate or extrapolate accurate results from just a key reading or two. But that is rarely hypothetical "middle gray", and more often the deepest shadow, along with highlight opposite boundary, where I want distinct gradation in the negative.

So no - even though I have worked with extreme contrast for decades, and have four matched Pentax Spotmeters (all still reading accurately, even though the first one is now held together by electrical tape) - flare is seldom an issue for me. I learned long ago how to handle that. And yes, I can detect fog or flare in a heartbeat once the negative is developed. But sometimes I deliberately introduce flare selectively into a scene, especially in 8x10 work - but that requires even fussier measurement in advance, because I want the effect just where I want it in the negative, and not anywhere else. Of course, a competent adjustable compendium shade is necessary to do that well.

It also helps to have along a film well matched to the anticipated contrast range to begin with, or malleable enough in development to handle the well, rather than beating half to death the wrong film with some Zone System compensating or "minus development" sledgehammer. But it's hard to teach old dogs new tricks.

Color film exposure is a completely different ballgame, since development is generally inflexible, or only barely so. There, deviation plus/minus from the midpoint is critical. But it is based on the saturation of given hues relative to that 18% box speed midpoint, rather than an abstract gray scale like in black and white work.

 

[Doremus Scudder]

Well, it takes experience just like with any other metering method. And given the scenario you describe, with just a small shadow in the midst of otherwise brightness, I seek out larger areas of the same depth of shadow somewhere nearby, at an analogous angle of view. ...

Yeah, me too, but that just compensates for the problem. Being aware that it's there, or potentially there, and finding a work-around is important. I was just trying to point out that the OP's metering of a black card which may have been in a rather bright environment may have contributed to the (likely) skewed results obtained.

Best,

Doremus

 

[Sirius Glass]

Drew,

Lens hoods (even toilet-paper tubes attached to the meter that block everything outside the meter's field of view) don't seem to do the job for me.

With my Pentax digital spot meters, the reading area is just a small fraction of the entire field of view, so there's still a lot of light that can be bouncing around inside the meter that isn't being directed to the small circular area being metered.

I notice a difference metering shadow values when they are surrounded by much brighter objects. In the case of, say, reading under the eaves of a white clapboard building from a distance, I can get the shaded area to just fill the metering circle, but the glaring white walls are still there in the meter's field of view. I'll get a reading of X for that shadow from that distance with that much bright stuff in the field of view. Now, if I walk up closer so that the entire field of view of the meter is filled with the shaded area, I'll get a significantly lower reading; maybe one or two EV lower, than the first reading. The illumination of that shaded area hasn't changed any, so it has to be flare in the meter that's causing the discrepancy. When I have those situations and I can't walk closer and meter the shadow without bright things in the field of view, I'll figure that my shadow-value reading is high and add some exposure, usually just a guesstimate based on how bright and large the surrounding bright areas are.

Try the same experiment with your spot meters; I'll bet you see similar flare.

Best,

Doremus

Well, it takes experience just like with any other metering method. And given the scenario you describe, with just a small shadow in the midst of otherwise brightness, I seek out larger areas of the same depth of shadow somewhere nearby, at an analogous angle of view. And having done so thousands of times before, it all becomes easy to interpolate or extrapolate accurate results from just a key reading or two. But that is rarely hypothetical "middle gray", and more often the deepest shadow, along with highlight opposite boundary, where I want distinct gradation in the negative.

So no - even though I have worked with extreme contrast for decades, and have four matched Pentax Spotmeters (all still reading accurately, even though the first one is now held together by electrical tape) - flare is seldom an issue for me. I learned long ago how to handle that. And yes, I can detect fog or flare in a heartbeat once the negative is developed. But sometimes I deliberately introduce flare selectively into a scene, especially in 8x10 work - but that requires even fussier measurement in advance, because I want the effect just where I want it in the negative, and not anywhere else. Of course, a competent adjustable compendium shade is necessary to do that well.

It also helps to have along a film well matched to the anticipated contrast range to begin with, or malleable enough in development to handle the well, rather than beating half to death the wrong film with some Zone System compensating or "minus development" sledgehammer. But it's hard to teach old dogs new tricks.

Color film exposure is a completely different ballgame, since development is generally inflexible, or only barely so. There, deviation plus/minus from the midpoint is critical. But it is based on the saturation of given hues relative to that 18% box speed midpoint, rather than an abstract gray scale like in black and white work.

I too seek out larger areas of the same or similar shadows rather than try to measure a small area that just bounces around the target area. I just never had the patience for that.

 

[Bill Burk]

I figure light meter flare is about the same as camera flare so what you meter is what you get.

 

[DREW WILEY]

Camera flare is even easier to control, at least with view cameras having compendium shades, or long lenses on smaller cameras with effective hoods etc. Unfortunately, one of my favorite convenience cameras is a "Texas Leica" Fuji 6x9 with fixed wide-normal 90mm lens difficult to shade. The only realistic solution there if directly facing the sun is to turn around and look for something else to shoot.

 

[Sirius Glass]

Camera flare is even easier to control, at least with view cameras having compendium shades, or long lenses on smaller cameras with effective hoods etc. Unfortunately, one of my favorite convenience cameras is a "Texas Leica" Fuji 6x9 with fixed wide-normal 90mm lens difficult to shade. The only realistic solution there if directly facing the sun is to turn around and look for something else to shoot.

OR wear a large Stetson and have very long arms to hold the hat as a sun shade for the lens.

 

[DREW WILEY]

I thought Stetsons carried a high risk of bent nose syndrome and gray beard growth. I couldn't afford a Stetson anyway when I had to ride the range as a kid. Briefly worked for a crew that set me on a half broken wild mustang. Those Nevada mustangs had tremendous stamina, but would throw you in no time flat if they sensed they could get away with it. My personal horse was an appaloosa, but too much of a spoiled pet to be a realistic working horse.

 

[Bill Burk]

I have a … calibrated Kodak step wedge that I bought 30 years ago for a silly amount of money.

That is the heart of a sensitometer. You only need to add a contact printing frame and a controllable light source.

 

[Doremus Scudder]

I figure light meter flare is about the same as camera flare so what you meter is what you get.

I'm pretty sure the optical system on my Pentax spot meter is nowhere as good as the ones on the taking lenses I'm using. Plus I don't really know what the internal reflections in the meter are like when compared to the bellows on my view cameras. All I know is that when I fill the viewing area on my spot meter with a shadow, I'll get a different reading than if the shadow is small and the rest of the viewing area has lots of bright objects in it.

I'm happy with walking closer or choosing surrogate shadow areas or compensating.

Best,

Doremus

 

[DREW WILEY]

Lenses aren't all the same. The mere fact that VC lenses are engineered with distinctly larger circles of illumination than the film area itself, for sake of movements, means that they deliberately take in way more surplus light than necessary for a one-degree (plus viewing area) spot meter by comparison, unless well shaded. But otherwise, no; you're not going to get a highly flare-resistant 3/2 dagor formula thousand buck lens on the front of a five hundred dollar light meter. Pentax was early in the game of effective multi-coatings; many meters don't even have them. And TTL meters jump through all kinds of hoops in order to make a reading.

 

[markbau]

So I just did another zone 1 and zone 8 test. It should be noted that the film had a best before date of Nov 2017 and had not been refrigerated although it was kept in a basement that never gets over 18C.

120 TX @ EI 200 developed 12 min in D 23 1:1 12 minutes Patterson tank 30 sec inversions.

Zone 1 .03 above fb+fog
Zone 8 .99 above fb+fog.

In the pictorial photos on the rolls the shadows look a bit thin even though I gave those pics plenty of exposure. (Rated at EI 200 and in full sun, sunny 16 rule and then open another stop)
The zone tests were metered with a Zone 6 modified meter. Is this lack of shadow detail due to the age of the film?
The D 23 was freshly made up 2 days ago
Can I deduce anything from the zone 8 density when the zone 1 was so low? Or can I still safely say that the neg could have used a bit more development?
Next test will be just purchased FP4+

 

[Bill Burk]

First thing I would do is hunt for a Time-Contrast graph for Tri-X and D-23 1:1. (I would make that graph for you if I were going to use that film/developer combo… but I don’t have plans right now to do that).

You got about 0.96/2.10 = 0.46 contrast, in 12 minutes. You should want about 1.20/2.10 = 0.57

Kodak Data Book, Processing Chemicals and Formulas for B&W (1954) says D-23 average developing time is about 19 minutes in a tank. I don’t know why you picked 12 minutes but let’s continue…

Red dot is what you got… this doesn’t have D-23 1:1 but suppose the time-contrast curve is parallel to D-76 1:1 and knowing what you got, I would try 16 minutes next time.

 

[markbau]

First thing I would do is hunt for a Time-Contrast graph for Tri-X and D-23 1:1. (I would make that graph for you if I were going to use that film/developer combo… but I don’t have plans right now to do that).

You got about 0.96/2.10 = 0.46 contrast, in 12 minutes. You should want about 1.20/2.10 = 0.57

Kodak Data Book, Processing Chemicals and Formulas for B&W (1954) says D-23 average developing time is about 19 minutes in a tank. I don’t know why you picked 12 minutes but let’s continue…

Red dot is what you got… this doesn’t have D-23 1:1 but suppose the time-contrast curve is parallel to D-76 1:1 and knowing what you got, I would try 16 minutes next time.

View attachment 298735

Thanks for your reply. I'm going out with the camera today so will use a roll of the same film and develop it tonight for 16 mins and report back.

 

[markbau]

Todays roll of TX 120 at EI 200. D-23 1:1 20C 16 min.

Zone I still at .03 above fb+fog. (The TX is a few years out of date but I can't imagine rating TX lower than EI 200) To the eyeball the Zone I density is definitely different to the film base.

Zone VIII now at 1.19 above fb+fog. Not quite at AA's density for diffusion enlargers but close.

The pictorial negs look gorgeous! Can't wait to print them.

Do you think I should try a 19 minute development?

First thing I would do is hunt for a Time-Contrast graph for Tri-X and D-23 1:1. (I would make that graph for you if I were going to use that film/developer combo… but I don’t have plans right now to do that).

You got about 0.96/2.10 = 0.46 contrast, in 12 minutes. You should want about 1.20/2.10 = 0.57

Kodak Data Book, Processing Chemicals and Formulas for B&W (1954) says D-23 average developing time is about 19 minutes in a tank. I don’t know why you picked 12 minutes but let’s continue…

Red dot is what you got… this doesn’t have D-23 1:1 but suppose the time-contrast curve is parallel to D-76 1:1 and knowing what you got, I would try 16 minutes next time.

View attachment 298735

 

[Andrew O'Neill]

Just for fun I had a few frames left on a film so decided to do a Value I density test. Using TX 120 I shot a black target on zone 1 at EI 200 and 400. Zeroing my densitometer on the film base the EI 200 reads at .05 and the EI 400 read .01.

In AA's book "The Negative" He says to aim for a Value 1 of 0.09 - 0.11 above fb+f. If I followed this I would be rating Tri X at EI 100. I'm very happy with my negs at EI 200 so don't plan to change anything but was wondering if anyone could explain the difference. The film was hand developed in D76 1:1 for 9 minutes, 30 second agitations.

If I had a couple of frames left, I would have shot the target at the EI that I normally use, and the last frame on zone VIII. Develop like I normally do, then read the densities. This would have given me quite a bit of info, such as was my develop time enough to get the zone VIII exposure on a density that would give me a zone VIII? If it was too low, extending the development time would correct that and lift the zone 1's density up (if it was low)...

 

[Bill Burk]

1.17/2.10 = 0.55 … I don’t see any reason to try for a higher contrast.

Age fog could have cost you some speed (unless Base+Fog is close to Base).

At that contrast (to rise 0.07) you are 0.13 away from Zone I reaching 0.10

By that reckoning (0.13 is close enough to round off and say you need to increase exposure by 0.1 = 1/3 stop) you can subtract one-third stop from speed = EI 160

 

[Stephen Benskin]

1.17/2.10 = 0.55 … I don’t see any reason to try for a higher contrast.

Age fog could have cost you some speed (unless Base+Fog is close to Base).

At that contrast (to rise 0.07) you are 0.13 away from Zone I reaching 0.10

By that reckoning (0.13 is close enough to round off and say you need to increase exposure by 0.1 = 1/3 stop) you can subtract one-third stop from speed = EI 160

Bill, great example of how even a virtual curve can yield useful information.

 

[markbau]

If I had a couple of frames left, I would have shot the target at the EI that I normally use, and the last frame on zone VIII. Develop like I normally do, then read the densities. This would have given me quite a bit of info, such as was my develop time enough to get the zone VIII exposure on a density that would give me a zone VIII? If it was too low, extending the development time would correct that and lift the zone 1's density up (if it was low)...

There isn't much use exposing a zone vii frame if you haven't got your film speed nailed down. Once you know you have a useable film speed by getting a decent density on a zone I frame then its time to see what you are getting on zone viii so you can work out a development time.

 

[Andrew O'Neill]

There isn't much use exposing a zone vii frame if you haven't got your film speed nailed down. Once you know you have a useable film speed by getting a decent density on a zone I frame then its time to see what you are getting on zone viii so you can work out a development time.

I use zone VIII, not VII to determine development time. Development time will effect your EI.

 

[markbau]

I use zone VIII, not VII to determine development time. Development time will effect your EI.

That was a typo, it should read zone viii. I don't agree that devlopment time affects your EI. I just did a test where I increased development from 12 minutes to 16 minutes on TX with D-23. zone i stayed the same, zone viii increased in density. I've read all of the Phil Davis newsletters but I believe that the low values get to where they are going to stay after about 50% of development. High values change according to development time. Of course stand development and 2 bath development like the Thornton method changes the equation.

 

[Andrew O'Neill]

That was a typo, it should read zone viii. I don't agree that devlopment time affects your EI. I just did a test where I increased development from 12 minutes to 16 minutes on TX with D-23. zone i stayed the same, zone viii increased in density. I've read all of the Phil Davis newsletters but I believe that the low values get to where they are going to stay after about 50% of development. High values change according to development time. Of course stand development and 2 bath development like the Thornton method changes the equation.

Ahhh... well, with HP5 it does, along with a couple other films that I use. That's why people use it for pushing.

 

[Stephen Benskin]

I don't agree that devlopment time affects your EI.

It depends on the method used. Density does continue to increase, but if you use the correct Delta-X criteria method for speed determination, the speed doesn't change very much with development. If you use a gradient that is proportional to the overall gradient, it tends to balance out differences in density where a fixed density method doesn't.

And while it was implied in a earlier post, perhaps the Zone System's biggest flaw is that it doesn't use curves. I believe using the use of two target densities basically out of context for Zone I and Zone VIII have caused so much confusion and wasted effort for so many over the years.

 

[Bill Burk]

@markbau @Andrew O'Neill you are both right.

The “first excellent print”-based speed (real speed) does not change dramatically when you go from 12 to 16 minutes.

In this specific case the speed did change - by “rise needed” divided by contrast; .07/.46 (from the earlier run), Mark saw a “slower” speed (just looking where curve crosses 0.1). In the earlier run he saw speed in the middle of 125 and 160. In the later run it was between that and 160. A twelfth of a stop difference, but rounds to newer EI 160 and the older EI 125.

These are Zone System speeds for use with Zone System metering (exposure by spotmeter reading placed on appropriate Zone). By incident meter or through the lens averaging camera setting the new speed is EI 250.

But the speed at which a “just acceptable print”-based speed (pushing) can be made increases fairly dramatically with changes in contrast.

Even with this new contrast of 0.57 and the findings that EI may be 250 for average metering, I wouldn’t hesitate to use the film at EI 400. I could get a “just acceptable” print from that.

 

[Bill Burk]

And I didn’t try to evaluate the Delta-X speed which is the one that corresponds to “first excellent print”. That is same as “speed where 0.1 crosses the curve” when the contrast is closer to 0.62