AGO Film Processor for home darkrooms

[BernardC]

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1 hour ago, Crem said:

With C41 I suspect there is some change in contrast and/or color shifts if temps drop and time increases. No idea how much though or like you said "within tolerance".

There's only one reliable way to find-out, which is buy some test strips and a colour densitometer! I suspect that it will be within limits for C41, meaning that any slight colour cast is easily correctable in printing. I'm sure that any diligent worker can get their process to be much more stable than most 1-hour photo labs.

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[Crem]

1 hour ago, BernardC said:

There's only one reliable way to find-out, which is buy some test strips and a colour densitometer! I suspect that it will be within limits for C41, meaning that any slight colour cast is easily correctable in printing. I'm sure that any diligent worker can get their process to be much more stable than most 1-hour photo labs.

Interesting! I didn't realize that's how this all worked. Makes total sense though. I see bulk Kodak test strips available online (not cheap!). I'll look into color densitometers next. I suspect this stuff is too pricy for me, but I sure would love to borrow a couple strips and a densitometer to run a test. This would make a good YouTube video.

[BernardC]

11 minutes ago, Crem said:

I'll look into color densitometers next. I suspect this stuff is too pricy for me, but I sure would love to borrow a couple strips and a densitometer to run a test.

Ironically, I found a densitometer that I didn't remember I owned, earlier this week. It came with an enlarger that I bought at auction years ago (and that I still use). It's a "Kodak Model 1 Color Densitometer" from the 1950s, no idea if it's accurate. It works by visual comparison, so you compare your test strip to a step wedge, and read the number on a scale when they match.

If you have any film labs in your area, you can probably buy a single test strip, process it, and ask/pay them to read it for you. You could also get lucky on the auction sites. I saw a lot of densitometers for sale back when 1-hour minilabs were closing. Keep in mind that some of them aren't autonomous, they plug into a C41 processor and use the processor's software to read/analyze the results and tell the operator what to do next (order more chems from your Noritsu distributor!).

 

[Crem]

14 minutes ago, BernardC said:

Ironically, I found a densitometer that I didn't remember I owned, earlier this week. It came with an enlarger that I bought at auction years ago (and that I still use). It's a "Kodak Model 1 Color Densitometer" from the 1950s, no idea if it's accurate. It works by visual comparison, so you compare your test strip to a step wedge, and read the number on a scale when they match.

If you have any film labs in your area, you can probably buy a single test strip, process it, and ask/pay them to read it for you. You could also get lucky on the auction sites. I saw a lot of densitometers for sale back when 1-hour minilabs were closing. Keep in mind that some of them aren't autonomous, they plug into a C41 processor and use the processor's software to read/analyze the results and tell the operator what to do next (order more chems from your Noritsu distributor!).

 

I appreciate all the info. I'll be playing around on Ebay tonight to see what I find. I love learning about this stuff.

[Crem]

I played with the AGO this weekend (4 rolls, 2 dev cycles with 2 rolls per tank). I used fresh Cinestill's C41 powder chems in the horizontal position. Quick summary is I experienced fast temp drops (Started at 39C, but ended around 34C to 35C. This wasn't a a scientific test, but overall the AGO automaticallly added a bunch more time to compensate and the negatives seemed a bit off. Not terribly off, but definitely some color/contrast issues. This meant more work in Negative Lab Pro trying to fix the scans. I was able to edit them to be acceptable, but they still look a bit off to me in ways I couldn't fully fix.

I then processed a couple rolls without the AGO. This time using nothing but a water bath (sous vide controlled), a Paterson tank in the vertical position, and very aggressive stick agitation (by hand without the AGO). Honestly the results came out better. There were no temp drops, I developed at the recommended Cinestill chem time, and I ended up with less work in NLP.

It seems like the AGO temperature drop caused color shifts. Yes it develops the negatives, but the temp drop seems to have a real impact that doesn't seem worth it. If the AGO had a built in heater it would be perfect. It's so small and compact. I definitely would recommend it for B&W, but not for C41.

I'm curious what everyone else thinks. Do you like the AGO for C41? Do you run into extra color shifts, contrast issues, etc with their time compensation?

Ping me if you want to buy a very slightly used AGO. I can't see myself using it again for C41.

Edited December 9, 2024 by Crem

[Einst_Stein]

What I want is reasonable consistent develop result. To deal with different color shift and density from bath to bath is No no.

If temperature drop speed makes difference with AGO, it would not work.  A constant develop temperature would be a better choice. 

The problem of measuring temperature on the go could be the retarded measurement time. What the reading of the thermal meter is not the immediate temperature of the chemical/film. 

 

Edited December 9, 2024 by Einst_Stein

[Doug A]

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If I was developing color film I would definitely be interested in the AGO. But I only develop B&W film so my temperature averaging scheme gets the job done with my stainless tanks. I store a one gallon jug of water and a one liter bottle of working solution fixer in the warmest place of the apartment in the winter months and the coolest place in the summer. My little bottle of Rodinal is in a safe place in my work room. I mix the Rodinal with water from the jug, put in a thermometer, and fill the other graduates with plain water stop, fixer, and water for the first step of the Ilford film washing method. When I am ready to start developing I read the temperature of the developer solution and the room temperature on the room thermostat. I average the two numbers in my head and look up the result on the Ilford temperature compensating chart and set the developer timer accordingly. (The temperature difference is seldom more than 2º or 3ºF.)

Edited February 8 by Doug A

[Einst_Stein]

The current AGO cannot develop acceptable consistent results for digital scanning.  The main problem is the retarded temperature measurement on the chemical. 

I don't know if it can be fixed with this simple enhancement. That is, add the environment temperature. This does not need another thermal meter, just let the user setting the environment temp manually. I think it is reasonable to assume the environment temp does not change rapidly. Or assume it is constant during the process time. Of course, this needs to upgrade the algorithm and the firmware. 

Edited February 9 by Einst_Stein

[250swb]

For developing B&W film the starting temperature is the important part, if it drifts downwards during the ten minutes or so dev time it hardly matters because most of the work is already done in the first minutes. If you are developing a film for scanning having the temperature drift down is an advantage as the lower the temperature the less active the developer and you get a lower contrast negative more suited for scanning. 

[TomB_tx]

Because the tank itself doesn't rotate with the AGO I suggested an insulating jacket could slow the temperature change. I've just taken to "dry heat" the entire tank to the upper temperature tolerance, and then doing a full fill (upright tank) wet preheat before draining and starting the normal developer step. I'm still satisfied with the results I'm getting, but I'm likely not as critical of results.

I also got their long tank setup to process 8x10 B&W prints, as my space is limited for trays, and I want to do more real enlargements for my grandkids. My 20x30" trays just don't fit my situation any more.

I gave them feedback about the rapid temperature change issue, and they replied they are planning something to resolve that. They were aware of the Leica forum discussion.

[250swb]

7 hours ago, TomB_tx said:

 

I gave them feedback about the rapid temperature change issue, and they replied they are planning something to resolve that. They were aware of the Leica forum discussion.

Is the temperature change an actual change or a false reading? In a normal five or ten minute development range for B&W or C41 a ‘rapid’ change can’t happen can it? 

[TomB_tx]

I think it's an actual change. For a single roll, the tank on its side there isn't much liquid in the tank, and the reel rotating moves it into the air constantly. Could likely reduce the change by keeping the tank upright and using a full tank of chemistry. With C41 I'd save and reuse so there wouldn't be more waste. Think I'll try that this week.

[PetPhoto]

sounds more like the temperature probes just dont work right. 

 

Or the settings are so off, it doesnt make a difference. 

[Vintage Visual]

Hi, I´m Arno from Vintage Visual- creator of AGO Film Processor. I´ll try to bring bit more clarity to this concept so you can understand it better.

AGOs approach on process stability is by looking temperature as variable and adjusting the development time accordingly. This allows us to make a device which is basically like JOBO but 5 times cheaper and smaller. Also, this ensures spot-on consistency, which is rather hard to achieve with traditional home developing tools.

1. How developing at lover temperature affects the negatives- In general, we have determined the process time at lower temperatures by using test strips* and densitometer. The idea during our experimentation with different chemicals is to find the exact time at lower temperature so the density values will stay the same as it would be developed at standard temperature (38°C). We test every chemical manufacturer product before adding to our Default program list as sometimes the chemicals behave differently. 

Developing at lower temperature only slightly affects the color balance, contrast (HD-LD) will stay the same and all the density values will stay in action limits**. Regarding color balance, if your chemicals don´t fall more then -5°C everything is OK. Going lower than this you get a slight green cast, something which can be adjusted in post-processing. Short blog post on that

2. How to maintain the temperature, ideally near 38°C- This is usual problem for AGO users that once they pour in the 38°C degree developer it drops up to -4°C, getting the feel that how is that possible and do my negatives come out good- they will. But still, for the good practice every color process in AGO has first step named as HEAT or PRE, the idea for this step is to heat up the tank before the developer. You can follow the thermometer during that steps and exchange the water for instance if it gets lower than 36°C. With that method you can heat up the tank before most important developer step, afterwards you won't get that big temperature drop as tank is already heated up. Also, it is good to heat your chemicals 1 to 2°C higher, so the average temperature during the processing is around 38°C.

*Test strips- these are precisely pre-exposed negatives with different density values, usually labs use these to determine the condition of their chemicals.

**Action limits- Action limits define the acceptable range of variation in film processing to ensure consistent color and contrast. If the measured densities stay within these limits, the process is stable.

Edited March 7 by Vintage Visual

[PetPhoto]

19 hours ago, Vintage Visual said:

Hi, I´m Arno from Vintage Visual- creator of AGO Film Processor. I´ll try to bring bit more clarity to this concept so you can understand it better.

AGOs approach on process stability is by looking temperature as variable and adjusting the development time accordingly. This allows us to make a device which is basically like JOBO but 5 times cheaper and smaller. Also, this ensures spot-on consistency, which is rather hard to achieve with traditional home developing tools.

1. How developing at lover temperature affects the negatives- In general, we have determined the process time at lower temperatures by using test strips* and densitometer. The idea during our experimentation with different chemicals is to find the exact time at lower temperature so the density values will stay the same as it would be developed at standard temperature (38°C). We test every chemical manufacturer product before adding to our Default program list as sometimes the chemicals behave differently. 

Developing at lower temperature only slightly affects the color balance, contrast (HD-LD) will stay the same and all the density values will stay in action limits**. Regarding color balance, if your chemicals don´t fall more then -5°C everything is OK. Going lower than this you get a slight green cast, something which can be adjusted in post-processing. Short blog post on that

2. How to maintain the temperature, ideally near 38°C- This is usual problem for AGO users that once they pour in the 38°C degree developer it drops up to -4°C, getting the feel that how is that possible and do my negatives come out good- they will. But still, for the good practice every color process in AGO has first step named as HEAT or PRE, the idea for this step is to heat up the tank before the developer. You can follow the thermometer during that steps and exchange the water for instance if it gets lower than 36°C. With that method you can heat up the tank before most important developer step, afterwards you won't get that big temperature drop as tank is already heated up. Also, it is good to heat your chemicals 1 to 2°C higher, so the average temperature during the processing is around 38°C.

*Test strips- these are precisely pre-exposed negatives with different density values, usually labs use these to determine the condition of their chemicals.

**Action limits- Action limits define the acceptable range of variation in film processing to ensure consistent color and contrast. If the measured densities stay within these limits, the process is stable.

Developing at lower temperature only slightly affects the color balance,

Thats like saying, a only slightly broken ankle is of no concern...  

 

The idea seems to be flawed.   You cant get the exact accuracy and reading from each and every temperature probe.