My first tray development - Issues

[Chuck_P]

A few remarks that may or may not be relevant to your situation.
I always develop sheet film in trays, one sheet at a time (unless it's just a technical test). I no longer use those Paterson style trays with the deep groves in the bottom, because I saw evidence that the design contributed to problems related to currents generated in the tray. Now, I only use Yankee type trays with shallow ribs on the bottom to keep film barely lifted off the bottom of the tray. (There are also flat bottomed trays by Cescolite, but you'd have to presoak film before using one of those trays for developer, or there's significant potential for the film to stick to the bottom)

I use Thornton 2-Bath often with sheet films and I have never had any kind of uneven development like what Chuck is seeing. I am skeptical that BTTB alone is responsible for the defects he got. In Bath A I agitate much like I would for any other developer: 30 seconds continuous at first and 5 seconds every 30 seconds. I am not gentle when agitating film in trays - I tip the tray alternating between left/right to top/bottom, and it's with enough force that I am at risk of sloshing developer out of the tray. Perhaps Chuck needs to try again and be more aggressive with agitation.
I do agitate through Bath B. I believe you do risk uneven development if you don't (with sheet film). I agitate for the first ten seconds, and then two rocks of the tray every 30 seconds. The only real (perceived) benefit of zero agitation in Bath B is a bit more edge effect to create acutance. I bet the difference in acutance is very, VERY minor, so you're potentially creating more problems than you solve if you opt for no agitation in B. That's just what my experience tells me, anyway, FWIW.

Question: how much film have you run through your A and B developer between refreshes? I tend to err on the side of caution with this developer, rarely processing more than 5 rolls of 120 or 5 sheets of 8x10 before dumping the chemistry and starting fresh. BTTB is so cheap to make that you can easily make fresh often, to avoid any problems with exhaustion or developer carryover. (Bath B accumulates Metol/sulfite and becomes more and more active)

I feel quite certain that Chuck's unevenness problem is entirely a technique issue. Maybe it's 2 or more issues compounding (wrong tray type + insufficient agitation?). I would do more tests and work to eliminate the potential contributors. I definitely feel that a divided developer has something to offer the photographer in certain situations (Like when some compression of the value scale is needed, but without losing value separation in parts of the curve) but there is some potential to get poor results without finessing the technique to fit your work habits. I firmly believe that the problem can be resolved once the responsible factor(s) is eliminated. I find Thornton 2-Bath to be a very useful tool in my darkroom vocabulary, and for me, it's been mostly trouble free and effortless, and the results well worth it.

I'm sorry I completely forgot to come back to your post...........I think it was when my brain was fried trying to navigate Koraks' inquiries..........just kidding, it was fruitful exchange for me. And I've seen those still life images before, those are nice.

I do use those Patterson trays that have the deep grooves on the bottom. The last Yankee trays I owned were 11x14 and were so flimsy, especially with liquid in them when lifting to pour. I find it very interesting that you are developing in trays and not experiencing any unevenness issues. Are you developing 4x5 in 5x7 trays or bigger 8x10 trays?

I think you are definitely right in that I need more vigorous agitation in the tray if I should try it again, I think that would be much easier to do in an 8x10 tray instead of the 5x7.

I'm skeptical of the edge effect/accutance idea behind the reason for no agitation in the B bath. This is the stuff running through my head on the subject:

Seems that no B bath agitation must be for this reason: It's more to do with the building up of the shadow densities while sitting in the B bath as the high value development is ended or coming to and end after the film has been in the A bath. This appears to be why, it is suggested, that with the two-solution process, your preferred shadow placement should be placed one zone higher than usual....to put more exposure in the preferred shadow(s).

Then, let the extra exposure that hits the preferred highlight develop without building too much density from carryover developer from bath A, as it will come to an end in bath B, giving that compensating effect...............meanwhile, as the film 'sits' in bath B alkali, the alkali reinforces the development of the extra exposure that was given to the preferred shadow(s).

So the problem I'm having is the uneven development noticeable in that continuous tone area of the negative. Yet...............the apparent the correction for that unevenness that works with my two-bath tank development, is to introduce agitation to the B bath, to keep the unevenness curse off the negative............that is, when there will be open skies and other continuous tone areas, like on my living room wall. I suspect that in a high contrast sun/shade forested environment that it simply won't matter if some uneven development occurs (tank or tray), you won't be able to see it.

Thanks for the observations and inputs.

 

[MattKing]

If you find Yankee or similar trays too flimsy, just nest them in a Paterson Tray that is sized appropriately. You can then handle the outer tray when you seek to agitate.

 

[Bill Burk]

Hey! Streaks changed orientation! They’re not flare/bellows reflections

 

[GregY]

I'm sorry I completely forgot to come back to your post...........I think it was when my brain was fried trying to navigate Koraks' inquiries..........just kidding, it was fruitful exchange for me. And I've seen those still life images before, those are nice.

I do use those Patterson trays that have the deep grooves on the bottom. The last Yankee trays I owned were 11x14 and were so flimsy, especially with liquid in them when lifting to pour. I find it very interesting that you are developing in trays and not experiencing any unevenness issues. Are you developing 4x5 in 5x7 trays or bigger 8x10 trays?

I think you are definitely right in that I need more vigorous agitation in the tray if I should try it again, I think that would be much easier to do in an 8x10 tray instead of the 5x7.

I'm skeptical of the edge effect/accutance idea behind the reason for no agitation in the B bath. This is the stuff running through my head on the subject:

Seems that no B bath agitation must be for this reason: It's more to do with the building up of the shadow densities while sitting in the B bath as the high value development is ended or coming to and end after the film has been in the A bath. This appears to be why, it is suggested, that with the two-solution process, your preferred shadow placement should be placed one zone higher than usual....to put more exposure in the preferred shadow(s).

Then, let the extra exposure that hits the preferred highlight develop without building too much density from carryover developer from bath A, as it will come to an end in bath B, giving that compensating effect...............meanwhile, as the film 'sits' in bath B alkali, the alkali reinforces the development of the extra exposure that was given to the preferred shadow(s).

So the problem I'm having is the uneven development noticeable in that continuous tone area of the negative. Yet...............the apparent the correction for that unevenness that works with my two-bath tank development, is to introduce agitation to the B bath, to keep the unevenness curse off the negative............that is, when there will be open skies and other continuous tone areas, like on my living room wall. I suspect that in a high contrast sun/shade forested environment that it simply won't matter if some uneven development occurs (tank or tray), you won't be able to see it.

Thanks for the observations and inputs.

Chuck for 5x7" film I bought some Pyrex meatloaf pans. They're smooth glass and maintain temperature well. I got 3 that i just use for developing film. They have high sides that are ideal for agitating without slopping out of the tray

 

[Chuck_P]

Hey! Streaks changed orientation! They’re not flare/bellows reflections

Yes, I noticed that, but it's not a vertically-oriented exposure, however it is positioned vertically in the SP445 tank, that must account for the different orientations of the unevenness. That way of looking at it was eye opening, but I knew it could not have been from added density due to flare/bellows reflections.

 

[Chuck_P]

Chuck for 5x7" film I bought some Pyrex meatloaf pans. They're smooth glass and maintain temperature well. I got 3 that i just use for developing film. They have high sides that are ideal for agitating without slopping out of the tray
View attachment 391592

That's a fine idea, thank you.

 

[Harry Callahan]

I am wondering for a few days now whether this uneven development also has to with the subject photographed, respectively with diffusion.
The curtains are high value, therefore high density on the negative and therefore most developing action is taking place there. This is where developer is used up most - but there is diffusion, making exhausted developer mixing with fresh developer. Respectively there will be more diffusion where exhausted developer does meet fresh developer.
This means diffusion should be highest at the curtains, but also on other high(er) values like the white parts of the blanket with the flower. In these areas there could be more "agitation" by diffusion than on the even and lower value wall - where fewer developer is exhausted.
Maybe that's why the curtain and the blanket make it through without irregularities, while the wall doesn`t.
Maybe agitation by diffusion is great enough on the high values, while it is too few at the low values.
On the sofa and the small table also are low values, but there also are bright(er) spots which should increase diffusion again.

If the subject was different, or the wall not of even brightness this uneven development may not have occurred.

 

[koraks]

This means diffusion should be highest at the curtains, but also on other high(er) values like the white parts of the blanket with the flower. In these areas there could be more "agitation" by diffusion than on the even and lower value wall - where fewer developer is exhausted.

I don't follow the reasoning that the rate of diffusion depends on the degree of development that takes place. Diffusion is not a function of development; it's thermodynamic given.

Your argument for local depletion is the thinking behind edge effects/acutance, but that plays out at a much smaller scale; sub-mm typically.

 

[Chuck_P]

I did poorly in chemistry class, go easy, if possible, lol. But I'm trying to learn more of what's actually occurring inside the tank or tray besides the film just looking the way I want it to when it's done.

The only book I have at the moment that speaks about individual developer components is The Negative. I'm reading the section about the Restrainer on pg.189. It says "potassium bromide is usually added as a restrainer to reduce fog level". But, there is no potassium bromide in the D-23-ish developer with BTTB, as it uses only 6.5g of metol instead of the std 7.5g for bath A. Toward the end of that section, it says, "Bromides are also a by-product of the development itself; since they form at the interface between the film and developer, they must be removed by agitation or they will inhibit further development."

My question is concerning how this may relate to tray agitation...........even though there is no PB as part of the bath A developer, is the quote above saying that bromides are forming at the film surface regardless, even if PB is not an actual component of the developer? And, if this is the case, could the uneven development actually be occurring in bath A due to too little agitation in the tray or in bath B due to no agitation in the tray? Both? [Side note: in my 445 tank development with BTTB, I only appear to get uneven development when there is no agitation in the B bath as clearly, there is plenty of agitation occurring in the A bath in a 5sec/30sec agitation scheme.]

This raises a second question in my mind, if it is the case, are bromides also occurring as a by-product of whatever development may be occurring in shadows in the B bath that............are not being removed by agitation therefore inhibiting further development and it is showing itself more easily in those continuous tone areas of the negative?

 

[koraks]

is the quote above saying that bromides are forming at the film surface regardless, even if PB is not an actual component of the developer?

Yes. Not just bromide ions btw. There'll also be a small amount of iodide ions, which have much the same effect, but a lot stronger. There may also be some chloride ions, but they have much less of an effect. The trio is often referred to as 'halides' (since they're part of the halide family in the periodic table).

could the uneven development actually be occurring in bath A due to too little agitation in the tray or in bath B due to no agitation in the tray?

With a two-bath developer, it's important to note that the actual development (mostly) takes place in bath B. So that's also the bath in which the halides will be released, since they're a by-product of development. Strictly speaking, Adams' quote in The Negative is unfortunately formulated as it's not technically correct. This doesn't really hurt in most cases, but in the case of two-bath development, the inaccuracy is very relevant.

All this still doesn't guarantee that agitation is only relevant for bath B (or bath A). For development to be even, the developer must be evenly distributed across the emulsion, so agitation in bath A will have an impact, especially if the duration in that bath is too short to reach an equilibrium between the emulsion and the surrounding developer bath.

are bromides also occurring as a by-product of whatever development may be occurring in shadows in the B bath that............are not being removed by agitation therefore inhibiting further development and it is showing itself more easily in those continuous tone areas of the negative?

The latter is certainly true; uneven development just stands out like a sore tooth in areas of even tone, while it may go entirely unnoticed in areas with lots of density variations.
As to the former, I'm not sure what you mean exactly - agitation will remove halides from the film emulsion through the combined effects of diffusion combined with a constant supply of liquid with a low halide concentration. This will happen in the second bath of a two-bath developer just like it will in a regular one-part developer.

Keep in mind that several effects can affect the evenness of development in bath B. Halide buildup can work as a restrainer, but diffusion of developing compounds out of the emulsion will have a similar effect. In a single-bath developer, the latter effect is not so relevant because there's a fresh supply of developer occurring with agitation. I think this is also the main reason why uneven development is potentially worse/more problematic in a two-bath system. In a two-bath developer, you're effectively balancing on a knife's edge w.r.t. agitation: it needs to be sufficient to get rid of excess halide buildup and it should be kept limited so as not to get rid of too much of the developer.

 

[Chuck_P]

Yes. Not just bromide ions btw. There'll also be a small amount of iodide ions, which have much the same effect, but a lot stronger. There may also be some chloride ions, but they have much less of an effect. The trio is often referred to as 'halides' (since they're part of the halide family in the periodic table).



With a two-bath developer, it's important to note that the actual development (mostly) takes place in bath B. So that's also the bath in which the halides will be released, since they're a by-product of development. Strictly speaking, Adams' quote in The Negative is unfortunately formulated as it's not technically correct. This doesn't really hurt in most cases, but in the case of two-bath development, the inaccuracy is very relevant.

All this still doesn't guarantee that agitation is only relevant for bath B (or bath A). For development to be even, the developer must be evenly distributed across the emulsion, so agitation in bath A will have an impact, especially if the duration in that bath is too short to reach an equilibrium between the emulsion and the surrounding developer bath.



The latter is certainly true; uneven development just stands out like a sore tooth in areas of even tone, while it may go entirely unnoticed in areas with lots of density variations.
As to the former, I'm not sure what you mean exactly - agitation will remove halides from the film emulsion through the combined effects of diffusion combined with a constant supply of liquid with a low halide concentration. This will happen in the second bath of a two-bath developer just like it will in a regular one-part developer.

Keep in mind that several effects can affect the evenness of development in bath B. Halide buildup can work as a restrainer, but diffusion of developing compounds out of the emulsion will have a similar effect. In a single-bath developer, the latter effect is not so relevant because there's a fresh supply of developer occurring with agitation. I think this is also the main reason why uneven development is potentially worse/more problematic in a two-bath system. In a two-bath developer, you're effectively balancing on a knife's edge w.r.t. agitation: it needs to be sufficient to get rid of excess halide buildup and it should be kept limited so as not to get rid of too much of the developer.

Thank you for all that, I will study on it as I move forward. The very last sentence in your response is enlightening because................in my 445-tank development with BTTB when generating my initial family of curves, I wound up reducing the agitation scheme for the B bath to 5sec/60 sec. This corrected the unevenness I was seeing with no agitation for the B bath. It sounds like that helped out with better balancing on the knife edge that you mentioned, perhaps there's room for even better balancing. At the moment, in my experimenting with two-bath development, I'm convinced that to maximize the intent behind its use, then I should try to get away with as little B bath agitation as possible. It's a bright sunny day with lots of snow, and the contrast in my living room scene is quite high at the moment.........another couple of sheets won't hurt.

 

[Milpool]

I did poorly in chemistry class, go easy, if possible, lol. But I'm trying to learn more of what's actually occurring inside the tank or tray besides the film just looking the way I want it to when it's done.

The only book I have at the moment that speaks about individual developer components is The Negative. I'm reading the section about the Restrainer on pg.189. It says "potassium bromide is usually added as a restrainer to reduce fog level". But, there is no potassium bromide in the D-23-ish developer with BTTB, as it uses only 6.5g of metol instead of the std 7.5g for bath A. Toward the end of that section, it says, "Bromides are also a by-product of the development itself; since they form at the interface between the film and developer, they must be removed by agitation or they will inhibit further development."

My question is concerning how this may relate to tray agitation...........even though there is no PB as part of the bath A developer, is the quote above saying that bromides are forming at the film surface regardless, even if PB is not an actual component of the developer? And, if this is the case, could the uneven development actually be occurring in bath A due to too little agitation in the tray or in bath B due to no agitation in the tray? Both? [Side note: in my 445 tank development with BTTB, I only appear to get uneven development when there is no agitation in the B bath as clearly, there is plenty of agitation occurring in the A bath in a 5sec/30sec agitation scheme.]

This raises a second question in my mind, if it is the case, are bromides also occurring as a by-product of whatever development may be occurring in shadows in the B bath that............are not being removed by agitation therefore inhibiting further development and it is showing itself more easily in those continuous tone areas of the negative?

There are more things going on besides bromide/iodide release. However ultimately when it comes to tray development techniques such as the one you are trying (ie manipulate the tray), I don't think you're really going to solve the uniformity problem. I'm not a proponent of two-solution development but I found tray manipulation methods to be problematic from a uniformity perspective using plain old single bath development.

 

[Chuck_P]

There are more things going on besides bromide/iodide release. However ultimately when it comes to tray development techniques such as the one you are trying (ie manipulate the tray), I don't think you're really going to solve the uniformity problem. I'm not a proponent of two-solution development but I found tray manipulation methods to be problematic from a uniformity perspective using plain old single bath development.

I don't know enough to doubt anything that you say, I'm experimenting and have questions. But how does it explain the past? How is it being done successfully today? How was it ever done so successfully when there were no daylight tanks to be had? I'm sure there were plenty of failures in those times as well when they looked at their big sky negatives and did a double take on them, but it was figured out, apparently. Why Kodak's single sheet tray agitation recommendations? There are some in this forum that apparently are successful with it. Having said that, I'd like to know if those same folks are even exposing negatives that even have large areas of continuous tone on them, maybe they're just not seeing it. If they are and still successful, then I ought to be able to replicate. Maybe it's coming down to that "knife edge" analogy that Koraks mentioned, even in the case of single bath developing.

 

[Milpool]

I don't know enough to doubt anything that you say, I'm experimenting and have questions. But how does it explain the past? How is it being done successfully today? How was it ever done so successfully when there were no daylight tanks to be had? I'm sure there were plenty of failures in those times as well when they looked at their big sky negatives and did a double take on them, but it was figured out, apparently. Why Kodak's single sheet tray agitation recommendations? There are some in this forum that apparently are successful with it. Having said that, I'd like to know if those same folks are even exposing negatives that even have large areas of continuous tone on them, maybe they're just not seeing it. If they are and still successful, then I ought to be able to replicate. Maybe it's coming down to that "knife edge" analogy that Koraks mentioned, even in the case of single bath developing.

Experiments are good. Questions are good. I'm not sure I understand the part about the past. People did the best they could with plates and later films. The results likely weren't all that great from a uniformity perspective. I've seen quite a few modern-to-contemporary examples. It is also possible to compensate in printing. Most of the LF photographers I can think of who cared about such things, preferred either the standard interleaving method in trays, or manual dip-dunk in open tanks (not as good, but less risk of mechanical damage when doing multiple sheets). The top-tier contemporary workers I know of who eventually gave up the interleaving method only did so when the Jobo Expert Drums came along (Tice and Sexton are two examples). Kodak generally recommended interleaving or dip-dunk. The tray manipulation method both Kodak and Ilford describe is inferior, but was perhaps deemed to be acceptable as a compromise. After all, "success" has no strict definition (although a few proposals have been put forth as acceptable levels of non-uniformity). What one person might call good uniformity, I might call blotchy, the way something is printed is an important variable, the subject matter obviously can make a big difference etc.

 

[Chuck_P]

I'm not sure I understand the part about the past.

That's was just my way to express that I felt there must have been a lot of "success" with it back in the day, but considering your other comments perhaps not a successful as I imagined. And I hadn't considered how it might be compensated for then and today in printing, I want to void that for sure but won't be doing any interleaving. Thanks for the input, all good stuff.

Anyway, I now have one more sheet to tray develop, either just being more vigorous with a different manipulation in a larger tray or following Doremus' suggestion. But I was hoping to get away with continuous agitation in the tray with the A bath, so not sure yet which one I'll do. And I have one more sheet to tank develop with lessening the B bath agitation by some amount from what I currently do at 5sec/60 sec.

 

[Harry Callahan]

I don't follow the reasoning that the rate of diffusion depends on the degree of development that takes place. Diffusion is not a function of development; it's thermodynamic given.

Your argument for local depletion is the thinking behind edge effects/acutance, but that plays out at a much smaller scale; sub-mm typically.

As far as i understand diffusion (also) means mixing of two different liquids. If you pour water and orange juice into a glass both liquids will mix until the solution is even.
When developing a film, there should be exhausted developer on the surface of the emulsion - but above should be fresh developer. Diffusion now will mix the exhausted dev. with the fresh dev. until an even state is reached. But as the film does continue to exhaust developer the mixing won`t stop - so there will be movement of liquid above the emulsion, which should act as some sort of agitation.
On a highlight part of the negative developer is exhausted faster than on a shadow part, which could result in more "agitation" by diffusion on the highlights.
More agitation means more even development. If there is a larger and even shadow part on the film, fewer "agitation" by diffusion could occur, which should result in less even development of that shadow area.

 

[koraks]

But as the film does continue to exhaust developer the mixing won`t stop - so there will be movement of liquid above the emulsion, which should act as some sort of agitation.

Hardly, and that effect drops entirely away against even the minute tremors caused by the heavy truck happening to drive by past the house.

The effect you identify doesn't have much practical relevance; it can come into play in a pure (semi-)stand development scenario where the film is left to sit perfectly still for 10+ minutes in the developer. At that point, you're going to start seeing effects like these influence the outcome. Not in a tray that's rocked every couple of minutes.

 

[Bill Burk]

I don't know enough to doubt anything that you say, I'm experimenting and have questions. But how does it explain the past? How is it being done successfully today? How was it ever done so successfully when there were no daylight tanks to be had? I'm sure there were plenty of failures in those times as well when they looked at their big sky negatives and did a double take on them, but it was figured out, apparently. Why Kodak's single sheet tray agitation recommendations? There are some in this forum that apparently are successful with it. Having said that, I'd like to know if those same folks are even exposing negatives that even have large areas of continuous tone on them, maybe they're just not seeing it. If they are and still successful, then I ought to be able to replicate. Maybe it's coming down to that "knife edge" analogy that Koraks mentioned, even in the case of single bath developing.

When you shuffle a half dozen sheets, only the top sheet has fresh developer, the other sheets in the stack only have the laminar layer. I think of shuffling constantly as giving similar agitation as small tank “every thirty seconds”.

I have had one ghost image appear, where two sheets went through emulsion to emulsion and the sensitometry strip on one sheet starved the pictorial content of the adjacent sheet where it touched the heavier exposures. I think a pair of normal negatives face to face would be less dramatic because there’s not usually that heavy an exposure. Still best to avoid emulsion to emulsion.

I do see edges developed more heavily because the fresh developer reaches them better than the middle. It’s not usually a problem but the effect is there.

Skies are where you see and need the kind of smoothness that tray processing can deliver.

 

[Chuck_P]

When you shuffle a half dozen sheets, only the top sheet has fresh developer, the other sheets in the stack only have the laminar layer. I think of shuffling constantly as giving similar agitation as small tank “every thirty seconds”.

I have had one ghost image appear, where two sheets went through emulsion to emulsion and the sensitometry strip on one sheet starved the pictorial content of the adjacent sheet where it touched the heavier exposures. I think a pair of normal negatives face to face would be less dramatic because there’s not usually that heavy an exposure. Still best to avoid emulsion to emulsion.

I do see edges developed more heavily because the fresh developer reaches them better than the middle. It’s not usually a problem but the effect is there.

Skies are where you see and need the kind of smoothness that tray processing can deliver.

I don't know what to say except that shuffling multiple sheets just sounds like a nightmare! No Multiple Sheets

 

[Harry Callahan]

Hardly, and that effect drops entirely away against even the minute tremors caused by the heavy truck happening to drive by past the house.

The effect you identify doesn't have much practical relevance; it can come into play in a pure (semi-)stand development scenario where the film is left to sit perfectly still for 10+ minutes in the developer. At that point, you're going to start seeing effects like these influence the outcome. Not in a tray that's rocked every couple of minutes.

I see. I came to this idea as the OP also tried bath B without any agitation and got these results. But i think the developing time only was 5 minutes, so this effect shouldn`t be happening.

 

[Bill Burk]

I don't know what to say except that shuffling multiple sheets just sounds like a nightmare! No Multiple Sheets

Multiple sheets is good. Just avoid digging corners into emulsion and don’t do them emulsion to emulsion.

 

[Doremus Scudder]

When you shuffle a half dozen sheets, only the top sheet has fresh developer, the other sheets in the stack only have the laminar layer. I think of shuffling constantly as giving similar agitation as small tank “every thirty seconds”.
...
I do see edges developed more heavily because the fresh developer reaches them better than the middle. It’s not usually a problem but the effect is there.
...

Indeed. I shuffle through the stack once every 30 seconds (up to six in a stack) and consider that agitation every 30 seconds. With PMK, I've been shuffling through the stack once per minute for the last half of development; it seems to enhance the edge effects. But PMK needs lots of agitation initially, so I'll shuffle even faster for the first minute (once through the stack every 15 seconds if I can manage it), then settle in to the once-through-every-30-seconds routine.

As for hot edges: Making sure not to push the film down into the developer rapidly helps a lot in preventing them. Just flopping the sheet onto the surface of the solution and then pressing down will always cause surge at the edges. See-sawing the film gently down reduces the surge.

Edge burning the prints helps too

Doremus

 

[Milpool]

As for hot edges: Making sure not to push the film down into the developer rapidly helps a lot in preventing them.

I agree with this part. Hot edges are not inherent. It takes some practice/testing to get the best results but if one takes care, the interleaving agitation method gives good results - better than most other methods - which is probably why it has always been a standard despite it requiring some concentration (particularly when it is not routine) and despite the risk of mechanical damage when doing multiple sheets.

Scratches can be a real problem though, apparently especially if you are doing high quality scanning (as opposed to say diffusion enlarging). I know a few reputable people who tray shuffled throughout their entire careers and never saw visible scratches until they started scanning their negatives, which revealed more subtle damage.

 

[Chuck_P]

Below on the left is my last image for my experimenting with tray development using BTTB. You can see the development in the wall area is much more uniform compared with the previous tray efforts, in fact it is very accurate with respect to the tonality of the walls and how they fade to darker in the corner. A thank you to @Ian C for messaging me and giving me an alternative to tray development that he uses and is successful for him. I used it for the photo on the left, but only for the A bath. It's basically very Kodak-like as far as developing a single sheet in a tray and I'm referring to as the "lift and hold" method in my notes. I used 8x10 trays with a full liter of solution, lift the near side hold for 6 sec, lift the far side hold 6 sec, lift the left side hold 6 sec, lift right side hold for 6 sec, then repeat for the duration. I can chime in and give more details I'm sure. I agitated bath B at 5 to 8 secs per 60 sec.

The one on the right is tank developed (SP445) at 4.5 min each bath with a standard 10sec initial agitation for both baths for comparison against the tray. Then 5sec per 30sec bath A and 5sec per 60sec bath B. The tray development was spot on with the tank development for evenness in the wall area and all areas. I actually developed a sheet in the thank prior to this one trying to reduce the bath B agitation to half of my standard, it was no good at the wall area, so with the tank I'll have to keep it at 5sec per 60sec in the B bath.

Exposures were identical for each. I placed EV 7 on Zone III for the chair back cushion below the blanket, and the highest value on the curtain fell on EV 15.5 (Zone XI+). On each negative there is good wiggle room to use in printing at both of those negative densities.

I'm just pleased that I was able to complete this little adventure into tray development with something I can call a success with apparent uniformity of development in continuous tone area of the negative. I also feel certain that if my other attempts were of scenes without continuous tones that I'd be able to use those negatives as well.

 

[koraks]

I think at this point if you want to optimize the process, you need to pick a different approach and not rely on a photograph of a wall. There is still some slight unevenness in the wall in both images, but the question is whether this is an accurate capture of reality or a process artefact (or a bit of both).

I also feel certain that if my other attempts were of scenes without continuous tones that I'd be able to use those negatives as well.

Yes, although at the other end of the spectrum, it's not guaranteed that if you shot a scene with a larger area of more even tone than this wall, the result would still be as good. Think of a frame in which 2/3 is filled with a pale blue sky with a slight gradient towards a lighter tone at the horizon. That short of scene is both common as well as notorious in terms of evenness of development.