Delta 100 in DDX 1+4 Film Test Curves

[Rafal Lukawiecki]

To all film chart junkies—I'm limited in terms of my sensitometer (see my other (there was a url link here which no longer exists) on the subject) and having read positive feedback from Dale's (there was a url link here which no longer exists), I have just employed it for this test of Delta 100, a film I am somewhat new to.

After doing a quick test, I established that the native exposure of SL-2 wastes about 3-4 strips (SL-2 uses a 21-step tablet) on this film. In order to get useful higher-density data without wasting too many underexposed strips, I have given each sheet precisely 2 consecutive exposures with the green, and separately, 2 exposures with the blue light. The green is short-duration, sounds like 1/4s, blue is longer, about 1 sec, so it means one strip received about 1/2s the other about 2s, so possibly in reciprocity failure, except Delta is supposedly well behaved in that region.

I have compiled, for you, three sets of charts (using my new curve/CI calculator, (there was a url link here which no longer exists) if you want to use it). One for just the green exposure (seems touch more contrasty), one for the blue (slightly softer), and then a third one, being a simple mean of the two. It seems my N dev time needs to be a bit shorter than Ilford recommendation (8 min vs. 12), which does not surprise me too much, as I aim for a slightly softer negative (CI about 0.58 as opposed to a more common 0.62, worth about a minute) and I tend to agitate more than typically demanded. I will be using the results of my tests for my next batch of real negatives, but I wonder if the curves look at all reasonable to anyone who has experienced this film in this developer.

Curves:

Development Time vs CI/N:

I do wonder how far those contrasts are from a red exposure. One day, I hope I can get my hands on a white-light sensitometer. Anyone wants to get rid of their EG&G?

 

[spijker]

Rafal & Michael, what agitation do you guys use?

 

[Rafal Lukawiecki]

Michael, many thanks for confirming this time range. I just remembered that you have posted, in the past, curves for Delta 100, I should have looked those up again before asking—apologies.

Spijker, I develop 2–6 sheets in a HP CombiPlan tank. I insert the holder into a pre-filled tank in the dark, put the lid on and I start continuous agitation for the first 30 s. Each agitation is a full inversion of the tank upside-down with lateral twist of 90 deg. Harder to describe, easy to do. The rate of inversions is such that in those 30 s I usually manage to invert it about 14 times. Then I triple-tap against my worktop to dislodge any bubbles, and leave it for 30 s. At every 30 sec interval I will invert it, the same way, 3 times and another triple-tap. Those 3 inversions take about 5 s, so they are energetic but not over-the-top. The last inversion is at 30 sec before the time-out, and I pour the developer through the bottom hole at -10 s. It finishes pouring out at 10 s past the end of dev time. This is the technique I have used since 2000, other than having reduced the rate of agitation from 4 inversions every 30 s to 3 every 30 s last year.

 

[K-G]

Rafal, I can second your findings with respect to development time for D-100 in DDX 1+4. 7-8 minute range for normal CI rather than the recommended 12.

I have also found the 12 min recommendation to give to contrasty negatives. When you use 7 - 8 min , do you still expose for EI 100 or do you reduce it ?

Karl-Gustaf

 

[spijker]

Thanks Rafal. I've always used the standard Ilford time & agitation (12 min, 4 inversions /minute) with 135 & 120 film. But I also wouldn't mind a bit less contrast. So I might try 10 min with the same agitation as I've used sofar. I only want to change one thing at the time.

Menno

 

[Rafal Lukawiecki]

I have also found the 12 min recommendation to give to contrasty negatives. When you use 7 - 8 min , do you still expose for EI 100 or do you reduce it ?Karl-Gustaf

Thanks for your confirmation, Karl-Gustaf. Regarding the EI, in theory, with reduced development, it ought to be lower than what this film (Delta 100 4x5) is rated as at the ISO standard contrast gradient, but I have been rating it at 100 for N, 80 for N-1 and 125 for N+1, so far. EI tends to be somewhat personal, hence all that testing, I suppose. Bear in mind, as I mentioned, I am relatively new to this film. I've been using HP5+ for best part of the decade, with maybe a dozen boxes of 320TXP in-between. I have done dev time/CI tests, as you may have seen from the curves I posted, but I have not done EI test yet. On my list.

 

[Rafal Lukawiecki]

Delta 100 in DDX 1+4 Much Faster Than ISO 100? Flare?

Ok, I've done a speed test of Delta 100 4x5 in DDX 1+4 20C today. I exposed 6 sheets through camera, placing the exposures on Zone I (4 stops down from metered), using a 210 mm lens that had its shutter recently calibrated, and a recently checked-up Pentax digi spot meter. I focused the lens at infinity (210 mm) and the frame was fully filled with the target, it was featureless. I used 1/60s and aperture range from 22 1/3 to 45 1/3 for the 6 exposures. This represented EI settings from 50 to 160. The target was an evenly daylight illuminated, outdoor, large sheet of mount board. It was measuring EV 12 2/3.

After developing for 7.5 min, which gives me CI=0.6 (as re-tested) I get fairly high, but consistent (linear in log(EI) terms, see plot) density readings:

[TABLE="width: 130"]

[TD="width: 65"]EI[/TD]
[TD="width: 65"]Density[/TD]


[TD="align: right"]50[/TD]
[TD="align: right"]0.39[/TD]


[TD="align: right"]64[/TD]
[TD="align: right"]0.34[/TD]


[TD="align: right"]80[/TD]
[TD="align: right"]0.29[/TD]


[TD="align: right"]100[/TD]
[TD="align: right"]0.25[/TD]


[TD="align: right"]125[/TD]
[TD="align: right"]0.2[/TD]


[TD="align: right"]160[/TD]
[TD="align: right"]0.17[/TD]

[/TABLE]

or, if you prefer a plot:

Now, this would mean I should be considering this film, even with reduced development, at N development, as EI 160 or even EI 200!

I have rechecked my steps, and unless my lens or the meter have developed an issue, I suspect flare would be inflating the numbers. May I ask any resident flare experts on patrol to validate my thinking? Have I made a different mistake?

Michael, what were your EI conclusions at a relatively "normal" gradient?

 

[Rafal Lukawiecki]

Thanks, Michael. I've looked at your procedures on the other thread, and I am not sure if I understand how do they overcome the potential issue of lens shutter, aperture, or meter accuracy—how did you check for that? Did you have a reference test, perhaps? Essentially, with an EI test we are looking for a point of absolute reference, such as a known exposure, at its heart. Flare could be an extra issue, of course.

Curves (see above) come from two tests: sensitometer-exposed strips for Dev time/CI tests, and a separate "curve" showing the EI/Density around the toe area alone. No other curves, have I missed one?

Infinity: took 210 mm between lens centre and film planes, as was not sure where the rear nodal point was.

What EI did you get?

 

[Mr Bill]

Hi, something I have suggested a time or two is to use a C-41 (color neg) film as a reference. It won't be exactly precise, but maybe close enough for you. The reasons I suggest this are 1) the C41 development is tightly controlled, and your process lab ought to be able to show you process control charts to prove it, and 2) my past experience with Kodak Portra 160 is that it has been very consistent.

Two disclaimers: the typical control strips don't always track closely with Portra, and my experience has been on the order of 6-8 years ago. My best guess is that Portra continues to be well controlled, although I'm not absolutely certain.

If you DO use Portra, you'll need to have a color densitometer (the speed is based on a combination of all three color layers), and you should use a good daylight source, as that is where Portra is zeroed.

Personally, I think I would just get an EI from practical shooting tests, just using the sensi wedge to dial in the development for contrast.

 

[Bill Burk]

I've been busy but want to say that the sensitometry curves are the "real" curves of the film. The camera exposure tests correlate to them ... any density on the film, you can assume is based on exposure that the film received. And that actual exposure would be the same ... as the exposure that caused that density on the sensitometry test.

Also... you might make a copy of your algorithm for CI that calculates the gradient of the ASA parameters and looks for the development time to reach "0.62". The 0.1 point of that curve would be your speed point "most likely to achieve rated box speed".

 

[Rafal Lukawiecki]

Gentlemen, many thanks for your suggestions. I've been on the road, travelling across US, hence slow on replies. Currently in the flood-affected parts of NM, heading for CO and WY. Clouds and weather quite spectacular, pity about the awful damage in CO...

I think EI 100 was what I got for Delta/DDX at a development time of 7.5min., and fb+fog density is always around 0.3-0.32 with Delta 100 in my tests.

Michael, your FB+fog seem bit high to me, I wonder if you use a different approach to sensitometry, perhaps? My reading of Delta 100 in DDX 1+4 gives FB+Fog varying from 0.1 at the shorter dev times to 0.13 at the longest I experimented with. Much less than your 0.3.

Mr Bill, and Bill, thanks for your suggestions. I think I will play it safe with EI, keeping it at 100, until I have a good few more printed negs. However, I will extend my R code to look for the ISO triangle condition. Still, without a calibrated exposure on the sensitometer, all this could help with would be to find the reference point on the curve, but not the EI, unless I am missing something, which is quite possible.

 

[Bill Burk]

Forgot to reply with the tech stuff...

In my thread about hitting the ASA triangle, I surmised that meeting the triangle does not necessarily assure you that you hit rated speed.

But as the thread progressed, it seems to have resolved that you get really, really close...

And so, when your processing meets the triangle with a standard developer (PE suggests D-76 straight for example), you can consider your "sensitometer" calibrated when you start with a fresh roll of a major manufacturer's film.

 

[Mr Bill]

And so, when your processing meets the triangle with a standard developer (PE suggests D-76 straight for example), you can consider your "sensitometer" calibrated when you start with a fresh roll of a major manufacturer's film.

Bill, I've never studied this sort of thing with B&W films, so I don't know how solid this is. But given that the old ANSI speed standards for such specified an agitation method (or "equivalent to,"), I wonder if one's own agitation methods might influence the speed. Likewise, I don't know how one's water supply might affect this, or even how well-controlled B&W films are. I'm not saying this is a bad method, just that I can't personally prove that it's good.

On the other hand, I have a long history with Kodak professional color neg films (low speeds, only). I've seen the results of thousands and thousands of sensi wedges, tracking a number of complete emulsions from when they were new, to random rolls up to a couple years past expiration. (These rolls have spent time in U.S. chain studios, and even in car trunks.). With few exceptions there was virtually no change. So I have a lot of confidence in these pro color films, that speeds will not be floating around. Unfortunately my experience is now a handful of years out of date, so I can't be certain about the current products.

Color has the same issues of processing variability as B&W, but the great equalizer is the process control strip. No matter what might go wrong in the mix, or with the water, or with the agitation, the control strip will still be the master reference as to whether conditions are ok or not.

Anyway, this is why I'm willing to recommend Kodak Portra 160 as a speed reference, but not anything else.

 

[Bill Burk]

...given that the old ANSI speed standards for such specified an agitation method (or "equivalent to,"), I wonder if one's own agitation methods might influence the speed. Likewise, I don't know how one's water supply might affect this, or even how well-controlled B&W films are...

I've read advice to verify sensitometer with a color negative film, and I believe it is good advice, partly because processing is more tightly controlled than home black and white.

But I have a hunch that it isn't difficult to attain full rated speed with black and white using a standard developer and developing to the ASA contrast parameters... If speed was extremely variable, we would have MORE silver bullet advice - especially if people were getting different results all over the place.

 

[Bill Burk]

A significant factor might be "hold time" - just don't develop the test film within an hour of exposing and you can bring that factor down to "less significant"

Another significant factor is the light source color temperature. But THAT factor - while it may impact speed - is less likely to impact CONSISTENCY.

So even if you can't be assured of a particular speed (or if you can't know the meter-candle-seconds of the light)... You have a fighting chance of being consistent. And that might be the most important outcome of developing to a certain contrast (measured by densitometer).

 

[macandal]

I'm sorry for reviving an old thread, but rather than start a new one, why not piggy-back on a similar question.

I know film testing is very personal, but I want to compare notes with any of you who may have been used the same film/developer combination. In the past I've screwed up this test so badly, so I want to make sure I've done it right.

• I am testing Delta 100 (4x5) with Ilfotec DD-X.
• I kept the temperature at 68F.
• I used the development times suggested by the Ilford tech sheet for this film which was 12 minutes intermittent agitation.
• I used the nikor tanks to develop the sheets.
• I used the Ansel Adams method as it appears on The Negative (using third stops--my lens indicates these third stops)
• I left the shutter speed constant and changed the f stops.

My results showed that my personal EI for this combination is 160.

Are my results comparable with those some of you may have had? I was not expecting an EI of 160. I was expecting something below the stated ASA of 100.

Thanks.

 

[K-G]

I am not really surprised as I have noted myself, and I have read that others also have, that 12 min with DD-X and Delta 100 gives a litle to contrasty negatives. I use to develop for about 10 1/2 min if the film was exposed in normal lighting conditions.

Karl-Gustaf

 

[macandal]

Karl, I have seen that others have also gone against Ilford's recommendation of 12 minutes for 1+4 and have developed at lower times like 7 or 8 minutes. How did you arrive at a lower development time?

So, at 12 minutes, do you think the EI I came up with, 160, is normal?

I will post my results later tonight, when I get home.

Thanks.

 

[macandal]

Here are the results of my test:



Ilford Delta 100 + Ilfotec DD-X
68F
12 minutes, intermittent agitation
Source: The Negative by Ansel Adams

Zone V: f5.6 1/60

[table="width: 500, class: grid"]



ASA
f
Shutter
Density
No Density


1.
No exposure (blank)
--
--
--
0.17
--


2.
Zone I
100
22
1/60
0.37
0.20


3.
1/3 stop less than #2
125
22 1/3
1/60
0.31
0.14


4.
2/3 stop less than #2
160
22 2/3
1/60
0.26
0.09


5.
Zone 0
200
32
1/60
0.22
0.05


6.
1/3 stop more than #2
80
16 2/3
1/60
0.40
0.23


7.
2/3 stop more
64
16 1/3
1/60
0.48
0.31


8.
Zone II
50
16
1/60
0.57
0.40

[/table]

 

[Bill Burk]

Here are the results of my test with 100TMAX and D-76 stock (1+0).

I've only drawn two curves here because I immediately saw something worth sharing.

Effective speed is indicated on my graph by following a straight line up where the toe of the curve crosses 0.10 net density.

At 13 minutes 30 seconds development time, I am very near the ISO parameters (dashed triangle) and very near ISO speed.

Notice I lose a full stop of speed when I drop from 13 minutes 30 seconds development time down to 8 minutes development time.

One thought I like to point out whenever talking about Zone System film speed tests... When you finally decide on development time for N, people often choose a development time slightly less than what meets the ISO parameters, so naturally the result is slightly lower speed (like 80 instead of 100).

I believe, Mario, that you also met the ISO parameters with your 12 minutes development time (I did a quick sketch of your data points and they look like if you continued the series it would achieve approximately 0.62 gradient).

You could take your findings as rock solid and run with 160 if you want.

And you don't have to listen to me on this point, but I would recommend calling your result 100 (trust that your lab technique is good, you hit the ASA triangle and manufacturer film speed is often our best benchmark)... Then note that your "system" seems to lead to +2/3 stop "error".

(I could also take my own advice and move my top scale to line up the ASA triangle with 100 for the same reason. But last time I moved the scale I had to move it back though).

 

[macandal]

You could take your findings as rock solid and run with 160 if you want.

And you don't have to listen to me on this point, but I would recommend calling your result 100 (trust that your lab technique is good, you hit the ASA triangle and manufacturer film speed is often our best benchmark)... Then note that your "system" seems to lead to +2/3 stop "error".

(I could also take my own advice and move my top scale to line up the ASA triangle with 100 for the same reason. But last time I moved the scale I had to move it back though).

Bill I'm afraid you lost me here. My 160 EI is correct and I should use that? Or use 100 instead because my test has a +2/3 margin or error? I don't understand???

 

[Bill Burk]

Bill I'm afraid you lost me here. My 160 EI is correct and I should use that? Or use 100 instead because my test has a +2/3 margin or error? I don't understand???

After writing that post, I've come around to think that your shutter is probably giving you 1/40 second instead of 1/60 (when used at small apertures).

 

[macandal]

After writing that post, I've come around to think that your shutter is probably giving you 1/40 second instead of 1/60 (when used at small apertures).

So what would be a possible solution? Shoot at a faster or slower shutter speed than 1/60?

Take my initial reading, f/5.6 at 1/60, and I hope I did my calculations right, zone I would be f/22 at 1/60. Since one of the concerns in this thread is that my shutter is not actually shooting at that speed at such a small aperture, then, using an equivalent exposure with a larger aperture would bring that to (to name two examples) f/8 at 1/500 or f/5.6 at 1/1000. Am I right? Did I do that right?

In other words, my zone I exposure f/22 at 1/60 is equivalent to f/5.6 at 1/1000. Right? That would eliminate the small aperture problem.

Or am I completely demented?

Thanks.

 

[Bill Burk]

Mario,

You could try a shot using a darker gray board (but not black). Meter at EI 100, place on Zone I exactly as before but now with a wider aperture and still at 1/60.

If you plan to change shutter speed, go slower. A dark gray board would help for this too.

A slightly slower shutter speed such as 1/30 or 1/15 would eliminate the small aperture problem by making the "opening and closing" time less of a percentage of the total exposure. But don't plan whole second or longer test exposures because then you start getting into reciprocity failure.

 

[macandal]

Mario,

You could try a shot using a darker gray board (but not black). Meter at EI 100, place on Zone I exactly as before but now with a wider aperture and still at 1/60.

If you plan to change shutter speed, go slower. A dark gray board would help for this too.

A slightly slower shutter speed such as 1/30 or 1/15 would eliminate the small aperture problem by making the "opening and closing" time less of a percentage of the total exposure. But don't plan whole second or longer test exposures because then you start getting into reciprocity failure.

I never use black. I always use a grey board. So, my suggestion to use f/8 at 1/500 of a second (if my metered board is f/5.6 at 1/60) would work too, right? I'm not going to use 1/60 since some of you think this may be wrong.

Oh, and no, I never use 1 second or more when doing zone testing.

Thanks.