Leader Density: D-76 vs Rodinal and others

I typically use D-76 1+1 or Rodinal 1+50 for developing my medium speed film (Tmax 100). I noticed when comparing leaders exposed to daylight, the film developed in diluted D-76 has what appears to be much weaker leader density as compared to Rodinal. The D-76 leader when held to the eye is not nearly opaque and objects in sunlight are easily visible through the leader. The Rodinal leaders are virtually opaque and it is difficult to see objects in sunlight through the leader. This is with a freshly mixed, aged a day, batch of D-76 using distilled water for mixing and dilution. The same distilled water is used for the Rodinal dilution.

I went back into old negatives processed with different batches of D-76 and observed the same differences, so that pretty much rules out a bad batch of D-76. Also, highlight densities on properly exposed older frames are weaker than Rodinal processed film. I am using fresh Kodak bags of D-76 and a several year old bottle of Rodinal. The old Rodinal blows away the D-76.

I am using manufacturer's recommended development times but with the vigorous Kodak recommendation for agitation for the D-76 (5 inversions/30 sec) and a much gentler scheme for the Rodinal (2 gentle inversion/1 min.). The D-76 negs are somewhat flat when compared to the Rodinal negs.

My questions:

Does the variation in leader density when exposed to daylight for minutes during loading, etc., occur because D-76 is a much 'softer working' developer compared to Rodinal? Or, perhaps, does it relate to the ph of the respective developers, i.e., borax vs sodium carbonate? Or am I just plain missing something here?

As an aside, a while back I had to use some HC-110 because I was out of D-76 and using Covington's developing recommendations, I got leader densities comparable to Rodinal developed leaders.

Intuitively, it seems to me that Tmax100 film exposed to daylight and developed in most developers for the manufacturer's recommended time would reach near opaque densities in the leader material. Somehow the D-76 doesn't compare.

A quick addition: I checked some leader material developed in Tmax developer a while back and had strong leader density with it as well.

Is there something peculiar about D-76 that doesn't develop leader material to maximum density? I am completely baffled here! I have used D-76 for many years along with Rodinal and simply compensated for the differences when printing. I can put out a decent print from either but the leader density issue finally has me wondering if D-76 negs are not fully developed and should be doing a better job.

From charts I have, it appears that both developers are reaching approximately the same development of CI 0.56 (Rodinal is spec'd in gamma but I concluded that gamma 0.65 is comparable to CI 0.56).

Any thoughts? Are you all seeing similar (weaker) leader densities in your D-76 processing?

Bottom line: I don't believe I am getting full development with my D-76 developed negatives.

I shoot Tri-X and develop in D76 and TD-16. Looks fantastic, but I am pretty sure that there are better developers you could use than D76 for Tmax 100 film. Xtol and HC110 for instance. A lot of people like it in Rodinal, as you do, as that developer works for many films. I tried Tmax and got flat negatives no matter what I tried it in. Just not for me.

The agitation scheme that you're using is very different from what I use for Tri-X. It gets just 30 seconds of gentle agitation, then 2 gentle inversions every 30 seconds, and none the last minute. Again, that's for Tri-X. I am reading now that Tmax calls for 5-7 quick inversions in 5 seconds only initially. I'm pretty sure it wouldn't require this sort of thing all the way through the development cycle. In fact, checking Kodak's instructions, it says to agitate it for 5 seconds every 30 seconds after the initial agitation regime.

Oh, and this is with FRESH D76? Mine goes strange after just 3-4 weeks, hence my move to TD-16.

I wouldn't worry about the density of the leader. Since D76 by nature is fairly compensating and Rodinal isn't until you greatly reduce agitation, you might see less dense extreme highlights from D76.

Those areas received a million times more exposure than the pieces of film you care about, and should, in my opinion, not be judged as an indication of anything of importance.

Thomas Bertilsson said:

Those areas received a million times more exposure than the pieces of film you care about, and should, in my opinion, not be judged as an indication of anything of importance.

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Thanks, Thomas, for the response. I don't think I knew D-76 was much of a compensating developer. Guess I'll have to do some research on the subject. It does appear as though the developer is exhausting itself on the heavily exposed areas. If one uses 250ml of developer per 80 sq. in. of film plus 250ml H2O for dilution, there shouldn't be any exhaustion. I'll do the next roll straight and see if there is a difference.

Fred Aspen said:

Thanks, Thomas, for the response. I don't think I knew D-76 was much of a compensating developer. Guess I'll have to do some research on the subject. It does appear as though the developer is exhausting itself on the heavily exposed areas. If one uses 250ml of developer per 80 sq. in. of film plus 250ml H2O for dilution, there shouldn't be any exhaustion. I'll do the next roll straight and see if there is a difference.

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My experience is that D76 develops a bit of a shoulder, while Rodinal doesn't unless you slow down agitation. That was just how I have seen those developers work from experience, and the shoulder, to me, makes it compensating.

Fred Aspen said:

From charts I have, it appears that both developers are reaching approximately the same development of CI 0.56 (Rodinal is spec'd in gamma but I concluded that gamma 0.65 is comparable to CI 0.56).

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How are you measuring your contrast index?

momus said:

Oh, and this is with FRESH D76? Mine goes strange after just 3-4 weeks, hence my move to TD-16.

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Yes, first roll was the day after I mixed it; the second roll was 2 days later. On the agitation, I deliberately use vigorous agitation to beef up the highlights but it doesn't seem to help. Must be something going on with the prep of the developer perhaps. I used about 100 degree water and mix in a 5L brown glass bottle. I then decant into 500ml Boston rounds with Saran seal and screw tops.

I never really noticed it before until I was looking at the negs on a light table. The difference popped right out immediately. Now it's starting to bug me.

ic-racer said:

How are you measuring your contrast index?

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Manufacturer's development time charts. Used Horenstein's book showing differences between calculation of gamma and CI to normalize.

I use supermarket distilled h2o and am now wondering if there is something with the water that affects D-76 but doesn't affect Rodinal.

Fred Aspen said:

Manufacturer's development time charts.

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Those won't have any meaning to you unless you have an ISO certified lab Manufacturer's development times are "suggested starting times." You need to determine your own development times.

To get a measurable value for one's film contrast you can plot out H&D curves and use a number of methods to get the "gamma" or "contrast index." A cheap-and-dirty method is to just measure d-max. If you have a light meter you can measure the film over the meter orifice. One stop equals 0.3 log d etc. So if the film blocks eight stops then the d-max is 2.4 log d etc.

So, if you don't have the means to make H&D curves, it is certainly reasonable to process your films to a favorite d-max that is known to make printable negatives.

If I remember correctly H&D curves sometimes decrease after reaching max density (i.e. the "black sun" effect). Maybe the phenomenon is happening to your film leaders with D76 but not Rodinal for some reason.

Must be a contamination issue. Although hard to believe that contamination would be an issue over 10+ individual one gallon batches of D-76.

That said, I just did clip test with PX125 for 6' in straight D-76. Virtually no difference between the clip test at 1+1 for 9', both samples came out darkish brown and translucent. The Rodinal clip test at 1+50 at 13' is seriously opaque.

Been using supermarket steam distilled water (Kroger brand) for mixing/dilution purposes. Another note, using the same distilled water product was a disaster with Xtol a couple of years back. Xtol usually lasted about three weeks before going TU. I went back to D-76 knowing Kodak uses magic powders in its formulation to allow processing/dilution with ditch/toilet water with no ill effects.

Kroger distilled water is steam distilled, filtered and ozonated. Is RO distilled water a better choice?

Any comments on what might be an alternative source for h2o for mixing D-76? Our tap water is recycled water that is treated for health purposes but would kill Xtol in 24-36 hours (probably due to its high iron content). We don't drink the stuff at all; only used for washing dishes/laundry and watering the lawn!

Looks like this batch of 76 is dying or dead. It's about 10 days old today.

BetterSense said:

If I remember correctly H&D curves sometimes decrease after reaching max density (i.e. the "black sun" effect). Maybe the phenomenon is happening to your film leaders with D76 but not Rodinal for some reason.

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That is what's so baffling! HC110 wasn't affected but 76 is! I'm beginning to think it is a distilled water issue.

ic-racer said:

Those won't have any meaning to you unless you have an ISO certified lab Manufacturer's development times are "suggested starting times." You need to determine your own development times.

To get a measurable value for one's film contrast you can plot out H&D curves and use a number of methods to get the "gamma" or "contrast index." A cheap-and-dirty method is to just measure d-max. If you have a light meter you can measure the film over the meter orifice. One stop equals 0.3 log d etc. So if the film blocks eight stops then the d-max is 2.4 log d etc.

So, if you don't have the means to make H&D curves, it is certainly reasonable to process your films to a favorite d-max that is known to make printable negatives.

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Good tip! Luna Pro F says 3 stops difference in light transmission between 76 and Rodinal leaders.

Edit: Stated another way, 76 blocks approx 7.5 stops; Rodinal blocks 10.5 stops. Or, about d-max 2.25 vs 3.15.

Would you consider that range within the norms for the developers? Or, should I develop another +50% in 76?

As each and any developer to do its job has to make any area of a negative exposed to max light go to max black it surprises me that there is a range of Dmax in leaders depending on the developer but this appears to have happened here and is backed up by another user's experience.

Why is it I wonder why some developers "run out of steam" so to speak compared to others?

Might it still be the case that something has happened to the D76 in question?

Unfortunately I have never kept my "black leaders" from different developers in order to compare but on examination against the filament of a 100W incandescent lamp I can't say I was aware of any difference when I tested the leader against the light. It was certainly not enough to ever have made me say: "Wow, this leader is less black than another leader in another developer"

Given that areas of normal negatives often have clear areas of max black then you'd expect complaints about D76 not achieving the whiteness in print that say a Rodinal processed negative can achieve.

Sounds strange to me

pentaxuser

Fred Aspen said:

Good tip! Luna Pro F says 3 stops difference in light transmission between 76 and Rodinal leaders.

Edit: Stated another way, 76 blocks approx 7.5 stops; Rodinal blocks 10.5 stops. Or, about d-max 2.25 vs 3.15.

Would you consider that range within the norms for the developers? Or, should I develop another +50% in 76?

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You stated in an earlier post that the D-76 negs were flatter than the Rodinal ones. I was about to write that you are comparing negs that are developed to different contrasts (pictorial contrast, not necessarily leader densities) and until you have adjusted development time to produce roughly equal contrasts, comparisons will reflect the degree of development rather than anything else.

However, now that you have made a densitometric measurement showing such a large difference in leader densities, my comment doesn't seem to explain such a difference.

Maybe there's something about D-76 which has made it so popular because it's forgiving, whereas Rodinal is brutally powerful. Maybe it's about developer exhaustion in your particular tank volume and dilutions? Perhaps you could try doing the D-76 test using your same dilution but larger developer volume (maybe enough for 3 rolls) to see if exhaustion is the cause.

Pentaxuser,

I agree! I did not think there would be much, if any, difference in Dmax between developers. I am still leaning toward the water as the culprit. Perhaps flouridation?

You mentioned another user experiencing the same or similar problem? Can you point me to the thread?

john_s said:

Maybe there's something about D-76 which has made it so popular because it's forgiving, whereas Rodinal is brutally powerful. Maybe it's about developer exhaustion in your particular tank volume and dilutions? Perhaps you could try doing the D-76 test using your same dilution but larger developer volume (maybe enough for 3 rolls) to see if exhaustion is the cause.

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My clip test was 1" of film in 8 oz. of 76. Shouldn't be an exhaustion problem with that combination.

Where's PE when you really need him??

Fred Aspen said:

Pentaxuser,

You mentioned another user experiencing the same or similar problem? Can you point me to the thread?

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Fred, sorry I may have phrased this badly. I was referring to your reference to what Luna Pro had said which seems to back up this idea of different developers creating different levels of black.

Other than that I don't think I have ever seen any thread identifying what you had found which initially you connected to the make of developer and now may wonder if there is something wrong with either that particular D76 or something wrong with the other essential liquid, namely water.

pentaxuser

Fred Aspen said:

Good tip! Luna Pro F says 3 stops difference in light transmission between 76 and Rodinal leaders.

Edit: Stated another way, 76 blocks approx 7.5 stops; Rodinal blocks 10.5 stops. Or, about d-max 2.25 vs 3.15.

Would you consider that range within the norms for the developers? Or, should I develop another +50% in 76?

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Your normal depends on how you print. Contact or projection print; condenser or diffusion, etc. As you may or may not know, typical sensitometers don't blast the film enough to get to d-max (if they did, the speed point wouldn't show up on a typical 21 step wedge). So I don't have any data on hand to help out and I don't have any exposed leader around right now to check, (just took the garbage out ) but if I find some I'll post the densities.

ic-racer said:

Your normal depends on how you print. Contact or projection print; condenser or diffusion, etc. As you may or may not know, typical sensitometers don't blast the film enough to get to d-max (if they did, the speed point wouldn't show up on a typical 21 step wedge). So I don't have any data on hand to help out and I don't have any exposed leader around right now to check, (just took the garbage out ) but if I find some I'll post the densities.

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Thanks! My wife, the chemist, seems to think it may relate to the ozonation process, which adds oxidants to the water, and the fact that 76 has a pH of 8+ where Rodinal has a pH of 11+ and may be less affected than the less alkaline 76. If that's true, then the 76 would tend to become weaker more quickly and would explain the weak Dmax and the extremely short life of Xtol.

I'm going to boil up a different brand of distilled water and let it cool and mix a new batch. Hopefully tomorrow I may have more to add.

Independent of printing workflow, I still believe most developers are similar/strong enough to produce the film's Dmax on leader material.

If you can use your lightmeter to check how many f/stops of light are blocked by the developed film leader...

It's not any more work to check your contrast with the same light meter.

Anytime you can spare two shots... make two shots where there is a large solid tone. Do the same thing you would do if you wanted to bracket 2 stops...

Shoot one shot at meter recommendation and a second shot 2 stops over that...

Then the difference your light meter indicates between the two developed shots on your negative...

Can easily be converted from f/stops to density - and it's the difference in density compared to the difference in exposure that tells you your contrast...

For the purpose of determining personal development times, this is a pretty simple test procedure.

Since you are not going to file it it does not make any difference.

I still don't understand what the leader has to do with anything. Even if you find an answer, how does it make us smarter?

Presumably you don't want to print the film leader - it is the negative images which you are going to be printing.

If you can rule out damaged chemicals, try making a "proper" contact-sheet, where the exposure given is a tiny fraction less than needed to give the paper maximum black, when exposed through the filmbase. Put simply, give the most exposure you can while still seeing the perforations compared to the filmbase. Make the contacts on Gd.2,5 paper. From the look of your negs you will see whether the exposure is over or under and what the contrast looks like in your images.

"Ideally" all the images should look very good and printable at this exposure so you can keep the enlarger the same height, and the exposure the same time and f/stop, to make an excellent work print. If this doesn't work, develop longer to increase the contrast (or vice-versa) and expose more to lift the image in the shadows (and vice-versa, especially with unexpectedly blocked highlights). Somewhere in there is the compromise you are looking for that will allow the different developers to get the most from the film you are using.

Thomas Bertilsson said:

I still don't understand what the leader has to do with anything. Even if you find an answer, how does it make us smarter?

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Thomas, I made an observation that 76 appears to be a much weaker developer than Rodinal as it will not develop a leader to max black as Rodinal will do. I am trying to determine if this weakness (3 full stops by my measurement suggested by ic-racer) is inherenent/intentional in the design of D-76 or I, somehow, keep mixing dodgy 76 with bad water or something else.

Did Kodak intentionally design 76 to roll off the shoulder so it will not develop beyond a density of roughly 2.3 and that's its limit while Rodinal will develop to well over a density of 3.0?

When I first observed this my first thought was that the negs are not fully developed and this proved the case when printing negs from 76 and Rodinal respectively. My D-76 negs are noticeably flatter than Rodinal negs. I originally expected that they would print very similarly when developed to similar CI.

Is this intentional or is my work flow flawed?

It's as simple as that.

Perhaps someone else will run a simple clip test of medium speed film exposed to daylight, developed in straight 76 and fixed normally, and checked for opacity. I cannot see anything through a leader developed normally in Rodinal whereas the 76 leader is simply translucent.