Clarification on Rotary processing of Adox.

[MattKing]

It just seem strange that a major company has not chosen to expand on its suggestion to do something which it knows will appear to fly in the face of conventional wisdom about what a user does when changing from intermittent to constant agitation

Does it "fly in the face of conventional wisdom"? I don't think it does. I think it is merely reflective of a preference.

 

[brbo]

both but what troubles me is that Adox has not taken any trouble to explain this at all It just leaves me uneasy about whether there is not something we are not being told by Adox

Adox is telling you more than other manufacturers.

BTW, slight speed drop with shorter rotary development is not something that Adox "invented".

Where is @aparat when you need him to bring some data into the debate?

 

[pentaxuser]

Thanks Matt. Can you say what you think Adox means when it says this:
"With B&W films, the physical/chemical combined effects of local developer exhaustion + cool-down during a regular agitation process (especially at 24°C), leads to increased speed utilization and compensating properties of the developer.

A development where chemistry is rotated continuously and is kept at same temperature, decreases speed utilization by about 1/3rd to 1/2 stop. It is advisable to slightly overexpose b&w films, when opting for rotary processing."

I assume that regular agitation in the first paragraph refers to intermittent agitation but repeated at set regular intervals? Would this be your interpretation as well? I thought that all intermittent agitation regimes were regular in that sense so this puzzles me a little as it seems a redundant word but it may be that this word was included because the translator felt that was the best English meaning of the original German?

So regular but intermittent agitation from 24C in a room of a lower but unspecified ambient temperature ( probably 20C ?) over whatever time is right for that unspecified film and unspecified developer results in increased ( but unspecified ) speed utilisation and compensating properties of the developer.

Does this mean that for say HP5+ the speed of it in a developer at 24C but in a room of a lower ambient temp would effectively be beyond 400 and it would have better compensating properties?

Can you help me with what increased compensating properties would look like on the negative and whether in your opinion I am likely to be able to notice this increased speed and increased compensating properties?

Whereas Adox seems to be saying that at constant agitation and a constant temperature this results in decreased speed utilisation of 1/3rd to 1/2 stop. Following from this phenomenon it is advisable to slightly over expose( again unspecified but presumably in the range of 1/3 to 1/2 stop)?

If I am right then if I move to constant agitation with the same HP5+ I need to lower its speed to 320/300 to ensure that my negatives ( ceteris paribus) would be exactly the same?

Is my assumption above correct?

I appreciate I have asked numerous questions along with numerous assumptions but any help you can give me in clarifying matters is appreciated

pentaxuser

 

[pentaxuser]

Adox is telling you more than other manufacturers.

BTW, slight speed drop with shorter rotary development is not something that Adox "invented".

Where is @aparat when you need him to bring some data into the debate?

I feel differently on your first point but in connection with your points 2 and 3 I wholeheartedly agree that data or better still, for those of us who like to see a test such as Andrew O'Neill does in a video would be greatly appreciated

I have neither the skill nor the equipment to do such things

pentaxuser

 

[MattKing]

Frankly, I think the statement from Adox reminds me most of Fred Picker .
I'm not sure that "speed utilization" is a recognized term of art, although it might be, or perhaps it reflects an unusual translation from a phrase in German that is a term of art.

 

[pentaxuser]

Frankly, I think the statement from Adox reminds me most of Fred Picker .
I'm not sure that "speed utilization" is a recognized term of art, although it might be, or perhaps it reflects an unusual translation from a phrase in German that is a term of art.

So what might it mean, Matt? I don't know enough about Fred Picker to work out what your reference is suggesting.

Oh and have you got any comment on my other assumptions and questions in #28

Thanks

pentaxuser

 

[Mick Fagan]

Pentax User, for Fred Picker information, there are plenty of his books available. Always get it from the horses mouth instead of a regurgitation by someone else, I've found that usually works best.

I'm hoping that you purchase a roll of film and do some tests yourself, then report back to us with regard to intermittent and constant agitation. Expose the whole roll at your normal film speed setting, then cut it in half and develop one half constantly, and the other half intermittently.

By using 20º not 24º to remove at least one other possible variable might be a good idea, this should be quite doable as you are not yet into summer.

 

[Kilgallb]

I looked at my instructions for the unicolor C41 kit. It seems counter intuitive but the small tank development is 3.5min at 102F, while the roller drum is 3.5min at 104F.

Perhaps unicolor anticipated a faster drop in temperature in a drum.

 

[MattKing]

I don't know enough about Fred Picker to work out what your reference is suggesting.

Fred Picker's insight was always interesting. However, his attempts to explain "why" something worked the way it worked weren't always the most reliable.

 

[pentaxuser]

Fred Picker's insight was always interesting. However, his attempts to explain "why" something worked the way it worked weren't always the most reliable.

There are lots of people with interesting insights into all sorts of things, Matt. The key is being able to establish what validity those insight contain. As it stands "interesting" by itself must be the most neutral and diplomatic word in the world

You've said nothing about whether my assumptions on what Adox is saying form any part of your interpretations but I'll assume that I should conclude from this that my search for your views on my assumptions will not bear fruit now

Hopefully someone with the skills and facilities may yet do a test and lets us know his findings. If not, then on the basis that there is some text from Adox on this and some belief here on Photrio that this is a real phenomenon I and I hope others in the interests of giving the "whole picture " will mention the Adox text when constant rotation v intermittent agitation next arises.

pentaxuser

 

[MattKing]

You've said nothing about whether my assumptions on what Adox is saying form any part of your interpretations but I'll assume that I should conclude from this that my search for your views on my assumptions will not bear fruit now

I don't really know how to respond to your assumptions, other than to say that I think you are inferring considerably more than one can reasonably infer from what Adox has shared.
Adox has told us what gives them the results that Adox prefers. I don't believe we can deduce any more than that, particularly as we don't know which films and which developers and which dilutions are involved.
I would suggest that what you read from Adox is similar to what you read from Kodak or Ilford/Harman: namely, the information given is a good starting point, and you should make adjustments to your taste.
Adox is a small enterprise and I don't know that I've ever seen from them the sort of detailed sensitometric data that is available from other, (formerly) larger enterprises. One generally needs that sort of data if one is going to engage in the more detailed "why" and "how" that I think you want us to engage in.
In any event, there are very few here set up to do the sort of controlled environment work that would reveal answers about your assumptions - I certainly am not.

 

[mshchem]

I don't really know how to respond to your assumptions, other than to say that I think you are inferring considerably more than one can reasonably infer from what Adox has shared.
Adox has told us what gives them the results that Adox prefers. I don't believe we can deduce any more than that, particularly as we don't know which films and which developers and which dilutions are involved.
I would suggest that what you read from Adox is similar to what you read from Kodak or Ilford/Harman: namely, the information given is a good starting point, and you should make adjustments to your taste.
Adox is a small enterprise and I don't know that I've ever seen from them the sort of detailed sensitometric data that is available from other, (formerly) larger enterprises. One generally needs that sort of data if one is going to engage in the more detailed "why" and "how" that I think you want us to engage in.
In any event, there are very few here set up to do the sort of controlled environment work that would reveal answers about your assumptions - I certainly am not.

Very well said!

 

[pentaxuser]

I don't really know how to respond to your assumptions, other than to say that I think you are inferring considerably more than one can reasonably infer from what Adox has shared.
Adox has told us what gives them the results that Adox prefers. I don't believe we can deduce any more than that, particularly as we don't know which films and which developers and which dilutions are involved.
I would suggest that what you read from Adox is similar to what you read from Kodak or Ilford/Harman: namely, the information given is a good starting point, and you should make adjustments to your taste.
Adox is a small enterprise and I don't know that I've ever seen from them the sort of detailed sensitometric data that is available from other, (formerly) larger enterprises. One generally needs that sort of data if one is going to engage in the more detailed "why" and "how" that I think you want us to engage in.
In any event, there are very few here set up to do the sort of controlled environment work that would reveal answers about your assumptions - I certainly am not.

Well we each of us, if we are interested in what Adox says, has to try and work out exactly what we need to do, if anything, based on the statements made by Adox I have stated what I think Adox might mean and I simply wondered what your thoughts might be when you read the same text but if you feel you cannot deduce anymore than that Adox has told us what gives them the results it prefers then OK

It was just that Adox appears to state what happens when you change from intermittent to constant agitation as a photographic fact, namely you should increase exposure slightly. Simply changing or for that matter not changing development time no matter how carefully you attempt to do this to get the right change to development time will not work. or so. It will not achieve the same negative or so I thought it might be saying. As brbo has said by way of confirmation, Adox did not invent this inescapable fact. It is simply a fact

However maybe as you seem to be saying, it is not a universal fact applicable to all films, developers. It is just what is required to meet the results Adox prefers. No more no less

Perhaps this was your point all along and I needed to read your responses more carefully to realise this but others such as brbo and alibada seem to suggest that what Adox stated was a fact

I was simply trying to "get to the bottom " of what is the truth by asking questions or stating what I saw as unknowns in the Adox statement

pentaxuser

 

[ADOX Fotoimpex]

This is interesting how things can be interpreted. Ofcourse I wrote this remark to help and not to confuse. The statement is refering to a change from a tested inversion process@ calibrated exposure to rotation.
Until the clash of the industry, rotation was used by many companies to find their development times. This made sense because it was easy to standardize.
Since 20 years however the new standard is actually tank inversion because most people refer to digitaltruth as a source for film developing times and they are figured out by home users of which the vast majority is using simple tank inversion.
This is why we base all our published starting times on tank inversion.
We have standardised this with a Heiland TAS. So all development times given by ADOX are for tank inversion.
Next to this we have extensive knowledge about these phenomena because we brought the CMS 20 process to its physical limits.
On this film hundreds if not thousands of development tests have been undertaken in the past 20 years. All with the goal to figure out "something" to keep calling it a 20 ASA film. Further up someone was smiling about the 24° plus cool down effect in combination with tank inversion and 50 seconds of standstill inbetween. Believe it or not: It gains almost 1/3rd of a stop! (on CMS 20).
I will edit the advise section now to make clear that our own published times are for inversion.
Naturally this does not apply to times found in rotary processors in the first place. Neither does it apply to C-41 (the main purpose for rotary processors in the past) by the way.

 

[ADOX Fotoimpex]

Intermittent agitation lets shadows develop more than highlights because highlight-development is slowed down due to exhaustion.
Rotary develops both shadows and highlights at the same rate. To prevent overdeveloping highlights, you must reduce development-time. That causes shadows to have less development. That causes film speed (EI) to drop. To compensate for that, you need to expose a little more.

Mark

There´s not much more to add to this. This is correct. The amount varies upon the intensity of the process change and the developer used. I cannot comment on film types but I would not see a reason why there should be a difference. I would expect more forgiving films to show less of an effect and more "binary" films like T-grains to show more shaddow detail loss.

 

[mshchem]

There´s not much more to add to this. This is correct. The amount varies upon the intensity of the process change and the developer used. I cannot comment on film types but I would not see a reason why there should be a difference. I would expect more forgiving films to show less of an effect and more "binary" films like T-grains to show more shaddow detail loss.

What in the heck do you mean by binary regarding T-Max films? Such nonsense. The TAS machines are certainly silliest too. More silly than any Jobo, which are silly but work very well indeed.

 

[ADOX Fotoimpex]

I would not call the TAS silly. It is imitating the normal process undertaken by the vast majority of our customers. It does not control the temperature like a rotary processor so from a scientific viewpoint of reproducing constant results it is inferior but since an estimated less than 0,5% of the users have such a rotary processing machine, we chose 10 years ago to base all our sensitometry on this way of developing film.
The TAS helps us to keep at least the human factor (difference in agitation) out.

The term binary in respect to tabular grains might be a little misleading. I agree with you. But I can explain what I ment.

Tabular grain emulsions are extremely difficult to produce. The difference between conventional and tabular is, that you control the production within very narrow conditions to produce only one crystal shape and a more homogenous size distribution. In a conventional emulsion there are also tabular grains but the percentage is low. I think the non ISO- standard for calling an emulsion a tabular grain emulsion is if you have more than 80% of tab-grains inside.
This might vary from manufacturer to manufacturer. I once read Kodak manages to reach 90% and even above.

Such an emulsion works slightly more "binary" like an old style emulsion where you have every imagineable shape of crystals which all ripen differently, take sensitizers differently and behave differently under the impact of photons and in the developer.

This is why you can make from two or more of such modern emulsions a perfect "curve" which is actually as an aim a straight line.
(Edit: There are other was of making modern "non"-Tabgrain emulsions to which the same applies).
If you expose and develop these emulsions well, you receive a superior image with a longer straight/linear part of the curve.

However if you start making alterations or "errors" (e.g. under exposure or overdevelopment) they are not as forgiving and images taken burn out in the highlights or die in the shaddows easier.
Maybe binary is not the correct terminology but this is what I ment.

 

[BMbikerider]

There´s not much more to add to this. This is correct. The amount varies upon the intensity of the process change and the developer used. I cannot comment on film types but I would not see a reason why there should be a difference. I would expect more forgiving films to show less of an effect and more "binary" films like T-grains to show more shaddow detail loss.

I will go along with that. I have always used a Jobo to process B&W films and also the recommended reduction in time. However I was close to having a failure with my 1st Foma 200 where the negatives were lacking in shadow detail. It wasn't until after, reading that the ISO speed was a little optimistic that I now always expose atv125iso instead of 200. I have never had a problem with he likes of Ilford FP4+ or Kentmere and always expose at the box speed.
The only time I don't use rotary is with Rodinal and that is always done as the bottle instructions say.

This brings me to another similar oddity. C41 colour film is always 3mins 15 secs either rotary or stand development with intermittent agitation which has always struck me as a little 'odd'.

 

[brbo]

C41 colour film is always 3mins 15 secs either rotary or stand development with intermittent agitation which has always struck me as a little 'odd'.

I always understood C-41 being continuous agitation, 38ºC, 3:15. Anything else, you are on your own.

Where did you read that with intermittent agitation it's the same 3:15?

 

[BMbikerider]

I always understood C-41 being continuous agitation, 38ºC, 3:15. Anything else, you are on your own.

Where did you read that with intermittent agitation it's the same 3:15?

I cannot rightly remember but it was a long while ago when I used only Agfa C41 dev and the instructions or guide was on the back of the lable you had to peel of. I wish it was still available because it was so very very stable and the results were constant. I do remember that the additional instructions if you were not using a rotary method, were to keep the tank and film in should be immersed in water around the same temp as the developer when it was poured in. The term 'around' struck me then as not very scientific.

 

[mshchem]

One more variable, I have 5 different Jobo machines, including the Duolab, it allows development of up to two rolls of 120 or 35mm. Continuous 1 direction rotation. I use it interchangeably with the other 2 way machines, color and black and white, no troubles. The print drums will streak, trying to develop sheet film, bromide drag. This machine was never intended for sheets. I does have 4 deep tanks, 1 L each to develop 8x10 prints. Pretty cool little machine ( YMMV, don't buy this in lieu of a real Jobo )

 

[pentaxuser]

I always understood C-41 being continuous agitation, 38ºC, 3:15. Anything else, you are on your own.

Where did you read that with intermittent agitation it's the same 3:15?

Well none of the videos or instructions about C41 and intermittent agitation seem ever to suggest that a time different to the standard 3 mins 15 secs needs to be used

Is the outcome with intermittent agitation the same? I cannot say in terms that can be measured but in terms of how the negatives look there doesn't seem to be a difference. I would have thought that by now somebody either in comments on these videos or in forums would be saying the outcome isn't the same and/or saying that more than 3 mins 15secs is required if you use intermittent agitation.

Maybe some are saying this and if you know of such people then let us know.

Can any of the C41 experts and those who have used intermittent agitation at the correct 37.8 degrees C comment on this ?

Thanks

pentaxuser

 

[MattKing]

If the C-41 process is fully within spec, then the results will be within spec if 3:15 is the development time.
If the C-41 process is not fully within spec, then the results may be improved (although not optimum) with a development time that varies from 3:15.
C-41 was designed for use by big commercial labs where the machines used the same development time all the time. So other adjustments were used in order to keep the results optimum.
In contrast, most black and white development processes were designed with the assumption that development times could be varied - in fact the variance of time is one of the best features of those processes.

 

[Steven Lee]

What in the heck do you mean by binary regarding T-Max films? Such nonsense. The TAS machines are certainly silliest too. More silly than any Jobo, which are silly but work very well indeed.

The Heiland TAS is by far the best piece of equipment I've ever bought. You get the most consistent and highest quality agitation imaginable and it's half the price of the cheapest JOBO. Moreover, it offers better temperature control than JOBOs because of a much larger volume of chemistry and absence of that silly temp-dropping lift. Try putting a thermometer inside the tank and see.

Basically it's a strictly superior film processor. I bought the rotary processor only for 4x5" and I still develop all of my roll film in the TAS. I am genuinely surprised by it not being more popular. People overestimate the value of the tempering bath, underestimate the drawbacks of rotation for B&W films, and underestimate the convenience of not having to agitate manually, especially during the wash cycle.

 

[mshchem]

The Heiland TAS is by far the best piece of equipment I've ever bought. You get the most consistent and highest quality agitation imaginable and it's half the price of the cheapest JOBO. Moreover, it offers better temperature control than JOBOs because of a much larger volume of chemistry and absence of that silly temp-dropping lift. Try putting a thermometer inside the tank and see.

Basically it's a strictly superior film processor. I bought the rotary processor only for 4x5" and I still develop all of my roll film in the TAS. I am genuinely surprised by it not being more popular. People overestimate the value of the tempering bath, underestimate the drawbacks of rotation for B&W films, and underestimate the convenience of not having to agitate manually, especially during the wash cycle.

Temperature control with the robot TAS is perfect as long as you maintain the ambient temperature. 100°F room temperature. Perfect. Might as well throw in NITROGEN ATMOSPHERE too.

The TAS is cool, I just don't know what it adds, except complexity, over manual agitation. I suppose for some exotic semi stand agitation etc?? That's a stretch for me.

It does look like fun, maybe I could find one used.