Thomas Bertilsson
Member
I've been away from APUG for a while, but wanted to post some findings here as I have worked my way through a lot of film and paper lately.
Many people write about unevenly developed negatives, streaks from sprocket holes, etc. Various explanations are offered with respect to what causes these problems, even ideas surrounding fixing the negatives have emerged.
First of all, 35mm and 120 need to be treated differently.
120 Film
Uneven development occurred when there was not enough movement of the developer liquid inside the tank. Since the film is relatively wide, you need a lot of movement of reels and/or the liquid inside the tank to accomplish 100% developer replenishment across the entire film width. Agitate three rapid full inversions every 30 seconds, or six rapid full inversions every minute. You can extend to agitating every two minutes if you want to hold back the highlights in high contrast scenarios if you want.
I recommend using one of the following two solutions:
1. Use a tank where the tank is a bit bigger than it needs to be (like an inch or so; I have two tanks like this), leaving room above the top reel such that the reels can move inside the tank. Also don't fill the tank to the top so that the developer has lots of room inside the tank to move around.
2. If you don't have a tank with room above the top reel, use a tank one size bigger than you need, so develop one roll of film in a two 120-reel tank, or three rolls in a four 120-reel tank. Put an empty reel on top and then don't fill the tank more than about half way up the top reel, so that there is plenty of room inside the tank for the developer to move around.
The result from using this method is perfectly even negatives - every time. Not even a hint of uneven development in solid areas such as skies. I've even photographed a completely flat tonality surface, just to verify that I'm doing things right.
Conversely, every time I use a tank where two reels barely fit, and the tank is filled to the top, I invariably get unevenly developed negatives.
35mm Film
35mm film requires different treatment, because of its sprocket holes. If your developer inside the tank has the kind of velocity that you get with the 120 method above, the liquid will flush through the sprocket holes and cause streaking - without failure.
With 35mm film I recommend the following solution:
Use a tank that precisely fits the number of reels you're developing, and giving them very little room to move around, and fill the tank almost to the top with developer. Use three rapid full inversions every 30 seconds, or six rapid full inversions every 60 seconds. You can extend agitation intervals up to every five minutes if you want, which will bend a shoulder in most films, and it changes the shape of the film characteristic curve.
Luckily, 35mm film has an image area that isn't even half the size of 120 film, so you don't need to move developer solution around as aggressively to replenish evenly across the entire film surface.
This method results in perfectly even negatives - every single time.
Conversely, if I use a tank where the reels can move around too much, or there's a lot of room for developer to move, I invariably get unevenly developed 35mm negatives due to the sprocket holes. This is 100% consistent.
This discovery of needing to treat 35mm and 120 films with different developing regime to obtain perfect results every time took a lot of trial and error.
Disclaimer: I use Hewes stainless steel reels in stainless steel tanks, and I realize that the reels don't move around in a plastic tank like a Paterson, where the reels are locked to the center column. You'll have to improvise and find your own way with those.
Also, I don't profess to this being the only way to obtain perfect results every time. But it sure works for me, and I have worked ALL of the kinks out of my film processing with this approach, and I can now happily shoot and print without having to worry about bad negatives. I hope you can benefit from my discovery.
I won't be checking in any time soon again, so I will probably not be answering any questions you might have.
Happy photographing, and happy printing!
- Thomas
Many people write about unevenly developed negatives, streaks from sprocket holes, etc. Various explanations are offered with respect to what causes these problems, even ideas surrounding fixing the negatives have emerged.
First of all, 35mm and 120 need to be treated differently.
120 Film
Uneven development occurred when there was not enough movement of the developer liquid inside the tank. Since the film is relatively wide, you need a lot of movement of reels and/or the liquid inside the tank to accomplish 100% developer replenishment across the entire film width. Agitate three rapid full inversions every 30 seconds, or six rapid full inversions every minute. You can extend to agitating every two minutes if you want to hold back the highlights in high contrast scenarios if you want.
I recommend using one of the following two solutions:
1. Use a tank where the tank is a bit bigger than it needs to be (like an inch or so; I have two tanks like this), leaving room above the top reel such that the reels can move inside the tank. Also don't fill the tank to the top so that the developer has lots of room inside the tank to move around.
2. If you don't have a tank with room above the top reel, use a tank one size bigger than you need, so develop one roll of film in a two 120-reel tank, or three rolls in a four 120-reel tank. Put an empty reel on top and then don't fill the tank more than about half way up the top reel, so that there is plenty of room inside the tank for the developer to move around.
The result from using this method is perfectly even negatives - every time. Not even a hint of uneven development in solid areas such as skies. I've even photographed a completely flat tonality surface, just to verify that I'm doing things right.
Conversely, every time I use a tank where two reels barely fit, and the tank is filled to the top, I invariably get unevenly developed negatives.
35mm Film
35mm film requires different treatment, because of its sprocket holes. If your developer inside the tank has the kind of velocity that you get with the 120 method above, the liquid will flush through the sprocket holes and cause streaking - without failure.
With 35mm film I recommend the following solution:
Use a tank that precisely fits the number of reels you're developing, and giving them very little room to move around, and fill the tank almost to the top with developer. Use three rapid full inversions every 30 seconds, or six rapid full inversions every 60 seconds. You can extend agitation intervals up to every five minutes if you want, which will bend a shoulder in most films, and it changes the shape of the film characteristic curve.
Luckily, 35mm film has an image area that isn't even half the size of 120 film, so you don't need to move developer solution around as aggressively to replenish evenly across the entire film surface.
This method results in perfectly even negatives - every single time.
Conversely, if I use a tank where the reels can move around too much, or there's a lot of room for developer to move, I invariably get unevenly developed 35mm negatives due to the sprocket holes. This is 100% consistent.
This discovery of needing to treat 35mm and 120 films with different developing regime to obtain perfect results every time took a lot of trial and error.
Disclaimer: I use Hewes stainless steel reels in stainless steel tanks, and I realize that the reels don't move around in a plastic tank like a Paterson, where the reels are locked to the center column. You'll have to improvise and find your own way with those.
Also, I don't profess to this being the only way to obtain perfect results every time. But it sure works for me, and I have worked ALL of the kinks out of my film processing with this approach, and I can now happily shoot and print without having to worry about bad negatives. I hope you can benefit from my discovery.
I won't be checking in any time soon again, so I will probably not be answering any questions you might have.
Happy photographing, and happy printing!
- Thomas
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