ID11 times different than D76?

[BetterSense]

The inside of HP5 film boxes says to develop 16 minutes in ID11 but only 12:30 in D76. I thought these two developers were the same? Is Ilford trying to sabotage competing developers by giving bad instructions?

 

[ic-racer]

Dilution?

 

[cliveh]

The inside of HP5 film boxes says to develop 16 minutes in ID11 but only 12:30 in D76. I thought these two developers were the same? Is Ilford trying to sabotage competing developers by giving bad instructions?

Yes.

 

[BetterSense]

This is from a fresh 35mm roll.

I usually don't trust the massive dev chart, and I usually find the kodak datasheets accurate at least for the developers they include. However the ID11 discrepancies here make me question the other data points.

Anybody care to cross-reference these with the MDC and/or kodak/Ilford datasheet to see which times appear correct?

 

[pentaxuser]

I have a feeling this thread or one like it has been posted before but I cannot recall the explanation, assuming there was one, which reconciles the difference.

The two developers are essentially the same and in nearly all cases the times are identical or within 30 secs of each other so this one is anomalous.

I suspect this large difference is simply an anomaly in the original data and nothing more sinister than that. I cannot recall if we received any response from Simon Galley but given that we may be in danger of casting aspersions in Ilford's direction he may respond on Monday or early next week when he is back at work.

A search to see if this issue has been raised before may be instructive. I wouldn't draw far-reaching conclusions as yet from what you have discovered so far

pentaxuser

 

[Gerald C Koch]

You need to check that both sets of times are to achieve the same Gamma or Contrast Index. Otherwise you cannot compare them.

Kodak uses Contrast Index rather than Gamma. The two values are calculated in a slightly different way but they are sufficiently similar to compare times.

 

[Arvee]

Here is a link that may help (post #2; apparently they are different):

http://www.l-camera-forum.com/topic/240347-id11-and-d76/

 

[gone]

Obviously the two developers are not exactly identical, or Ilford would have given identical times. Maybe they just mean that its Ilford's version of D76. The times are different. At 1:1, I believe Kodak gives 11 minutes, and if you look at Ilford's box it says 13 minutes at 1:1. The 16 minutes (16 1/2 actually) only comes into play if you shot it at 800 ISO, not 400.

But my preference is to use the D76 full strength for 7 minutes w/ HP5, which is almost exactly what Ilford recommends if you use their ID11 at full strength. It's a grainier film than Tri-X no matter what you do, which is why I never got on w/ HP5.

 

[RobC]

I thought D76 was changed quite a while ago so that it could be packaged in one bag and not two but my memory may be wrong. i.e. D76 and ID11 are NOT identical in make up but produce results which are close enough that you would be hard pressed to tell the difference.

 

[Gerald C Koch]

ID-11 and D-76 are essentially identical. They may differ in small ways that do not effect their action. By this I mean such things as what chelating ingredient they use for hard water.

 

[Gerald C Koch]

Kodak has numerous patents to permit developers to be packaged in a single container. Ilford does not. However this in no way changes the characteristics of the two developers.

 

[Bruce Osgood]

I think you will find Kodak uses 1:1 to mean 2 (1+1), and Ilfords to mean 1 (stock ). That's been my experience.

 

[nworth]

Michael R's comment is pertinent. Manufacturers usually test their own products very extensively and accurately, but those of other manufacturers may not receive as much attention. I'm sure Ilford, being moderately large, is more careful than most, but their testing of HP-5+ wit D-76 was probably not as extensive as it was with ID-11. In most cases, recommended development times for other people's stuff are what worked more or less properly for someone. They often do not have the extensive sensitometric and field trials of the manufacturer's products. That would just be too expensive. The recommended times from third parties should be regarded as guesses and points of departure.

The recommended times will no doubt be for the packaged products. Packaged products sometimes differ a little bit from published formulas. For instance, Kodak makes small changes to permit D-76 to be packaged as a single powder. Ilford at one time added some proprietary ingredients to ID-11. Over many years, the changes Kodak makes to D-76 have been shown not to make any difference in performance or development time. But who knows.

 

[Ian Grant]

ID-11 and D-76 are essentially identical. They may differ in small ways that do not effect their action. By this I mean such things as what chelating ingredient they use for hard water.

It's more correct to say that they were essentially identical as were other clones from various other companies. However these days they have slightly different buffering hence the different times.

Ian

 

[RobC]

identical means nothing different. Its like a binary switch, either it's on or it's off. There is no inbetween. Essentially identical means similar which means NOT IDENTICAL. They may produce almost exact same results but not necessarily with exact same processing.

Question was why is processing time different. Well this may be one reason. Besides I can almost gurantee you that Kodaks and Ilfords testing procedures are not indentical and that they won't ever get exact same results with same materials so it's not surprising their times differ slightly.

 

[pentaxuser]

The strange thing is that in a lot of cases the times are identical. I'd have thought that buffering, agitation, contrast index etc would have resulted in appreciably different times for almost all, if not all, combos of film whereas in the case of stock ID11 and stock D76 the times in the case the OP quotes are the same.

It is only when the 1+1 times are used that the times differ and then they differ not by a little but by quite a lot so what changes in the case of HP5+ when you move to 1+1 and why aren't all the times for the range of films changed by this kind of appreciable margin?

pentaxuser

 

[Gerald C Koch]

Essentially identical = different in no meaningful way.

 

[BetterSense]

The "N" times are the same. It is only the "push" times which are different. It seems very reasonable to me that there may be different ideas of what it means to push film "1 stop" or "two stops" (has that kind of thing ever been formalized by ASA or DIN or ISO? e.g. a 1-stop push is a contrast index of .85 or something?) Kodak may be more conservative here; they do uphold the ISO speed standard whereas Ilford admits that it's speed ratings are made-up. Also, kodak don't recommend pushing TMY at all for a 1-stop underexposure, showing they are conservative when it comes to pushing. Even so, if Kodak and Ilford differ on this, I find it odd that Ilford would choose to promulgate the "inferior" kodak times rather than it's own.

 

[Jeff Bradford]

The notion that Ilford would sabotage their film customers for purchasing Kodak developer is disingenuous. The published times are merely guidelines to be adjusted within personal parameters. In other words, test it and see what works best.

 

[pentaxuser]

The "N" times i.e. box speed times are different by 2 minutes using 1+1 dilution so does Kodak or Ilford suddenly decide that they will used two different standards at 1+1 whereas at stock they are the same.

Are you sure that Kodak uphold the ISO speed standards but Ilford apparently take a more cavalier approach to such measurement, based on what you have said?

Seems incredible to me

pentaxuser

 

[BetterSense]

I didn't notice that even the "N" times for diluted D76 were different.

Ilford datasheets contain clear wording to the effect that they do not use the ISO speed criteria, but rather the "speed" numbers are based on a "practical evaluation of film speed", which, let's admit it, means they just decide to call the film 400. I'm ok with the film, and proper ISO testing is probably expensive. Luckily other mfgs still do use the ISO methodology, so at least we can compare.

 

[RalphLambrecht]

The inside of HP5 film boxes says to develop 16 minutes in ID11 but only 12:30 in D76. I thought these two developers were the same? Is Ilford trying to sabotage competing developers by giving bad instructions?

I always found them to be identical. and Ilford extremely honest and giving good advise.

 

[pentaxuser]

Ilford datasheets contain clear wording to the effect that they do not use the ISO speed criteria, but rather the "speed" numbers are based on a "practical evaluation of film speed", which, let's admit it, means they just decide to call the film 400. I'm ok with the film, and proper ISO testing is probably expensive. Luckily other mfgs still do use the ISO methodology, so at least we can compare.

I hope that you do not mean exactly what you have said and there is room for Ilford to conclude that you have simply misinterpreted what you think Ilford has said

In the public domain which is where we are on APUG I feel you may be sailing close to what may be "libel" in the legal definition of the word.

This is an open forum where users should be able to express their opinions but I think you should think carefully before making any other statements of this nature which move your statements a long way from an opinion which is legitimate and towards an unfounded allegation which could be considered damaging to a company's reputation.

pentaxuser

 

[BetterSense]

DELTA 3200 Professional has an ISO speed rating of ISO 1000/31º (1000ASA, 31DIN) to daylight. The ISO speed rating was measured using ILFORD ID-11 developer at 20°C/68ºF with intermittent agitation in a spiral tank.
It should be noted that the exposure index (EI) range recommended for DELTA 3200 Professional is based on a practical evaluation of film speed and is not based on foot speed, as is the ISO

From the datasheet. All the FP4, HP5, and Delta datasheet have similar wording.

I guess delta 3200 is the only one that has a different number from the ISO speed on the box, at least among films I have checked. On that stand corrected.

 

[ic-racer]

Please do not clutter the forums with misinterpretations of clearly established facts. The Ilford films are ISO rated; is says so on the box. The EXPOSURE INDEX of Ilford films is "not based
on foot speed, as is the ISO standard."