difference between home- and lab-developed negatives

[futile1981]

I develop my 35 mm film at home, I use c-41 fuji or Tetenal chemicals, and normal fujicolor film... I've been doing it for a while, it's not something I do only once in a while as a fun hobby or something, I'm serious about it, so I'm always careful with details, I use the exact right temperature, don't use exhausted chemicals, etc. And I do get very good results, I am totally happy with what I get.


BUT... Yesterday in my archive, I found some rolls (10 or so) that a lab had developed for me last year. I took out the negatives immediately and put them next to the negatives I had developed at home (I used many different rolls for comparison, so that it's not biased).


There is some serious difference!


The lab negatives clearly have more contrast. My negatives usually have a brownish mask on them. My negatives look a little too yellow, while the lab negatives have a dark magneta tone. I see that in the photos as well, the lab photos have a beautiful magneta tone (not too much).



So, firstly, how do you compare home- and lab-developed film? I want to know, can you say that with a machine you basically can get much better results (given that it's a good lab and that they take good care of everything)?


And also, please give me some input on the brown/yellow mask and lack of contrast in my negatives, what can be the cause? What can I do to improve that?


Help me think.

 

[Photo Engineer]

Good home and lab developed films should be virtually identical. Mine are just that.

If they differ, you or the lab are doing something wrong somewhere.

Negatives should be clear orange with negative dye images. Otherwise they have retained silver or silver halide, or they have some other fault such as under development.

PE

 

[Gerald C Koch]

For reasons of economy many commercial labs use their chemicals to exhaustion. The belief is that any color shift can be corrected during printing. This caused one photo writer to remark that their were only two primary colors; puke and burple. Puke is greenish yellow and burple is bluish purple. Prints are usually too puke or too burple. You need to find a reputable lab. As for your own negatives, developing color film is not difficult but denands attention to such things as time, temperature, and agitation.

 

[stefan4u]

Dear futile.

I had different masked films during my earlier attempts too. In my eyes this is a side effect of the BLIX.

Since years now I use separated bleach and fixing bathes, and the mask is virtually identical to good commercial results.

About the contrast difference…
Personally I like negatives more, who are a bit on the soft side, so if you can print them well (optical print, no scan) I would be happy with the result.
BUT if the chemicals are fresh, development time and agitation are OK, this sounds somehow like under temperature. What is your developer temperature if you drain it? Maybe you have to increase the process temp a bit to get the 100 degrees F in the average.
If you do a dry prewarm step, how long do you exercise it? I’ve found that nothing below 30 min. is sufficient to prewarm the films / reels and the drum. (maybe my cellar is a bit fresh..). This is why a lot of people prefer a wet prewash with temperated water (preferable 2 cycles, each 30 sec.) prior development.
There are divided opinions about this prewash, on the one side it’s minimizes the temperature drop of the developer (filled in to cold drums), on the other side it leads to minor variations of the colour curves. In the very most cases this is not noticeable with bare eye.
A further method to get less temperature drop is simply using more developer. One litre for 4 films (135/36) are doing quite well. By the way, this leads to a further idea. These 4 films per litre in one run, are anyway THAT standard. If you decide to take (for example) a jobo multitank 5 and use only these 560 ml of chemicals, as stated on the drum, you are exhausting the developer too much. (at least if developing the regular 3:15 min)

Regards,
Stefan

 

[foc]

"For reasons of economy many commercial labs use their chemicals to exhaustion"

I find that hard to believe. The cost of commercial chemicals for labs and minilabs is quite small compared to the over all operation of a lab. The chemical cost of C-41 processing in a minilab can be as low as 0.30 Euro depending on the purchasing power of the lab. Most minilabs use leader card film processors. These machines are are very reliable, if properly maintained, and will produce excellent results. The chemicals for these machines are mixed internaly in the machine and the processing tanks are automaticly replenished on the amount of film processed. Therefore the chemicals never get a chance to be exhaused.

Since these processors are automated, they will pump new chemical into the tanks. If for some reason this can't happen, the machine will alarm and not allow any further processing to take place. If the chemical level should drop in a tank the same will happen. If no new chemical is added to the machine, again the same will happen. If for some silly reason the operator tries to reprograme the rep pump rep rate, to try and save chemical, the tank level will drop and the machine will alarm and not allow any further processing to take place until the error is sorted.

What can cause C41 processing problems in mimilabs and bigger labs is not maintaining the C41 process. By this I mean good housekeeping, processing and reading process control strips, washing cross over racks, measuring rep pump output etc. If this isn't done then the lab is flying by the seat of their pants regarding quality control and frankly in my opinion shouldn't be in business.

 

[Photo Engineer]

With replenishment, there is no such thing as exhaustion! So, using to exhaustion implies that the lab is not replenishing, but I know of no lab that does not replenish. In fact, most machines (IIRC), signal the operator regarding replenishment rates and etc. I have to agree with "foc".

PE

 

[futile1981]

Hey Stefan,

that's such a good point about the BLIX! I do suspect that it has sth to do with my BLIX because I can see that my developer is fresh and clear. In the Tetenal chamicals I get, there is one BLIX, bleach and fixer are not separate, I used to use fuji chemicals for a short while and fuji does have separate chemicals...

So you recommend that I use separate bleach and fixer? What chemicals do you use?



The temperature... Although I'm very careful with that one, but now that I'm thinking about it, recently I've been pre-washing less and less, I usually use water, but many times I have ignored it recently... And thinking some more about it, it makes perfect sense; if my film/tank is at room temperature (20) and I add my developer which is usually at 38, the difference in temperature is so high that I guess it would make the developer lose half a degree immediately!


You had two very good points, I really really appreciate it!



Please don't forget to comment on my first question, the chemicals, what you used to use before and what you're using now


Reza

 

[hrst]

Do a forum search for C-41 blix, you'll find a lot of stuff. The Tetenal process is not a standard C-41 process but their own variation, so everything is possible. Photo Engineer has stated over and over again that blix with C-41 film is likely to cause problems. On the other hand, it has worked just fine for many people. However this might be a cause. I don't buy Tetenal anymore.

For the temperature, you can use TWO successive pre-wash steps with carefully measured water temperature. Make sure to drain the water well before pouring in the developer. However, this would cause a minor shift in contrast and color, not noticeable with bare eye from the negs. Something is really wrong if the Dmin looks notably different within the same film. But, don't forget that between different films, there are differences in Dmin color, and hence, only the end result is meaningful.

 

[Photo Engineer]

There are reports here of the single part blix being the lowest quality, and the two part blix being acceptable to the users. No one here (AFAIK) has done a side by side comparison. I have! All film blixes commercially available have some degree of the "bleach bypass" syndrome. Desaturated color, higher contrast, and grainy pictures.

You are the only possible judge.

PE

 

[stefan4u]

Dear futile.

A Blix is not the best option, if it is fresh and active it will work OK, but leaves a different coloured mask. This is visible, but at most times not a big problem. Adapt filtration and you should get fine prins. The basic problem with the blixes is to keep them stable and active in the needed concentration (Reductive and oxidative components decomposes themselves). So the shelf life is quite short, depending of the desired quality it is more a expensive one way product. Don’t use these monopart chemicals at all.
In lower concentrations, as needed for processing paper prints, a blix works fine…

But in my eyes your problem is still focused on the temperature / activity of your developer. You will have at least 2-3 degrees Celsius temperature drop if you develop without sufficient prewarm/prewet. This leads to a quite a noticeable underdevelopment, as you remarked.

Do some measurements, take a complete drum with reels, fill it with an equivalent amount of temperated water, imitate your normal agitation and measure the temperature in the drum after 1:30 till 2 min. and after 3:15 min. Than you easily can calculate how much the temperature declines, and what your actual average processing temperature is. Don’t be too scared

Do the same experiment with a prolonged prewarm or a double prewash step, you will see that the temperature drop will be a lot less!
Than increase your process temp a slightly, maybe to 102 °F and see what you get in a new run.

Now you will have quite a well approach to the desired temperature, and maybe have to add 10-15 sec to the development time for fine tuning. If you do not over exhaust your developer (1 Litre / 4 Films 135/36 at 100 asa) you / your films should doing fine now.

My favourite chemicals, will not help you very much, the developer is homebrewed, the bleach is a champion /mydoneg air bleach, fixer is tetenal NQ-3 (both minilab chemicals). Prior homebrewing I had flexicolor (lovely) and tetenal but most times separated bleach and fix stages, it is simply a lot cheaper (and better) in the long run.

Regards
Stefan

 

[Athiril]

There are reports here of the single part blix being the lowest quality, and the two part blix being acceptable to the users. No one here (AFAIK) has done a side by side comparison. I have! All film blixes commercially available have some degree of the "bleach bypass" syndrome. Desaturated color, higher contrast, and grainy pictures.

You are the only possible judge.

PE

I noticed this on the Tetenal kit somewhat a few years back when using it, not so much the desaturation though.

 

[futile1981]

There are reports here of the single part blix being the lowest quality, and the two part blix being acceptable to the users. No one here (AFAIK) has done a side by side comparison. I have! All film blixes commercially available have some degree of the "bleach bypass" syndrome. Desaturated color, higher contrast, and grainy pictures.

You are the only possible judge.

PE

Ok, so you have actually 'studied' this and concluded that single part blix is fairly inferior in general, very interesting, thanks for commenting!

 

[futile1981]

Dear futile.

A Blix is not the best option, if it is fresh and active it will work OK, but leaves a different coloured mask. This is visible, but at most times not a big problem. Adapt filtration and you should get fine prins. The basic problem with the blixes is to keep them stable and active in the needed concentration (Reductive and oxidative components decomposes themselves). So the shelf life is quite short, depending of the desired quality it is more a expensive one way product. Don’t use these monopart chemicals at all.
In lower concentrations, as needed for processing paper prints, a blix works fine…

But in my eyes your problem is still focused on the temperature / activity of your developer. You will have at least 2-3 degrees Celsius temperature drop if you develop without sufficient prewarm/prewet. This leads to a quite a noticeable underdevelopment, as you remarked.

Do some measurements, take a complete drum with reels, fill it with an equivalent amount of temperated water, imitate your normal agitation and measure the temperature in the drum after 1:30 till 2 min. and after 3:15 min. Than you easily can calculate how much the temperature declines, and what your actual average processing temperature is. Don’t be too scared

Do the same experiment with a prolonged prewarm or a double prewash step, you will see that the temperature drop will be a lot less!
Than increase your process temp a slightly, maybe to 102 °F and see what you get in a new run.

Now you will have quite a well approach to the desired temperature, and maybe have to add 10-15 sec to the development time for fine tuning. If you do not over exhaust your developer (1 Litre / 4 Films 135/36 at 100 asa) you / your films should doing fine now.

My favourite chemicals, will not help you very much, the developer is homebrewed, the bleach is a champion /mydoneg air bleach, fixer is tetenal NQ-3 (both minilab chemicals). Prior homebrewing I had flexicolor (lovely) and tetenal but most times separated bleach and fix stages, it is simply a lot cheaper (and better) in the long run.

Regards
Stefan

I'm totally going to do that, using water I will figure how much temperature drop would happen if I don't pre-wash, I'm very curious myself. I told you, last night when I seriously thought about it, it sounded so stupid! A tank, with 2 or even 3 rolls of film inside, all at room temperature, and you pour a 38degree liquid in there, and leave it for than 3 minutes, and you agitate aggressively and everything, OF COURSE that liquid is gonna lose a few degrees by the time the process is done!


Anyways


Thanks again,


Reza

 

[hrst]

What, you don't have a tempered water bath?

It's usually done so that you have a large tub of water where you hold your tank and chemicals. You use a precision controller heater on the tub, or if you don't have one, you just measure the temperature every 2-3 minutes and add a bit of hot water when needed. Well, with C-41, a large tub alone stays constant for 3'15, but for E6, you need to add hot water to keep the temperature up.

Well, you can do without a water bath too to an acceptable level, but you have to experiment first. You just need to measure the temperature at the beginning and at the end of the process to calculate average temperature, and adjust your starting temperature until you get an average of 38 deg C. It depends on tank brand and size, room temperature and your agitation style, this is why you have to test it first with water. It might be that 39 deg C works, and of course with two cycles of 39 deg C prewash. IIRC, I once measured 2 deg C temperature drop (from 39.0 to 37.0) with a two-film Jobo tank at room temperature of 23 for 3'15 process time.

 

[futile1981]

What, you don't have a tempered water bath?

It's usually done so that you have a large tub of water where you hold your tank and chemicals. You use a precision controller heater on the tub, or if you don't have one, you just measure the temperature every 2-3 minutes and add a bit of hot water when needed. Well, with C-41, a large tub alone stays constant for 3'15, but for E6, you need to add hot water to keep the temperature up.

Well, you can do without a water bath too to an acceptable level, but you have to experiment first. You just need to measure the temperature at the beginning and at the end of the process to calculate average temperature, and adjust your starting temperature until you get an average of 38 deg C. It depends on tank brand and size, room temperature and your agitation style, this is why you have to test it first with water. It might be that 39 deg C works, and of course with two cycles of 39 deg C prewash. IIRC, I once measured 2 deg C temperature drop (from 39.0 to 37.0) with a two-film Jobo tank at room temperature of 23 for 3'15 process time.

I will do it today and post an update here, I myself am very curious about the size of the temperature drop...


About the tub, well, intuitively, I believe if I do that pre-washing carefully so that everything is at let's say 38.3, I don't think the developer would lose temperature (during the process) beyond the 'optimal' range, I will test it anyway though

 

[Athiril]

If your ambient isn't extremely low. A plastic tank does very well. Due to heat insulation, once the film and tank itself is at processing temp via presoak.

 

[hrst]

It WILL drop below the limit, unless you are in a very hot room! As said above, it dropped by 2 deg C when I tested (causing an average error of 1 deg C). Much more than the standard margin of 0.15 deg C, and enough to cause clearly visible problems when not taken into account. The agitation causes more heat transfer through the plastic. Plastic tank is not a proper heat insulator. It has a large surface area.

But this is not a real problem as you can compensate this by using higher starting point. This is probably the easiest way to do C-41, and while not perfectly repeatable, it can be very close to a good process.

If your room temperature varies a lot, you need to repeat the test for different room temperatures. I would say it is quite different for 20 deg C than for 28 deg C!

 

[futile1981]

Alright, this is the situation:


I used the following:

- One Paterson Super System 4 tank
- 3 reels
- No film on the reels
- 1 liter of liquid (water)


Two cases:

1. No pre-wash. So my tank and reels are cold, actually at room temperature, which was 19.
2. Pre-washed, for one minute, with 37.8-degree water


For both cases, I pour 1 liter of 37.8-degree water, and I treat it as "developer", I agitate and everything, after 3.15 minutes I pour the water (developer!) out and measure the temperature.



The temperature drop is massive, and surprising enough, it is massive for both cases! When I pre-washed, the drop was smaller but still dramatic.

no-pre-wash case temperature: 34.9 ---> drop of 2.9 degrees

pre-wash case temperature: 35.4 ---> drop of 2.4 degrees



and don't forget that there was no film even. I didn't expect it honestly, especially for the second one WITH prewash. The difference is only half a degree!

It seems that agitation makes the liquid lose its temperature pretty quickly, and having it pre-soaked (pre-washed) does not seem to be that helpful.




What do you think? Do these numbers (or one of them) surprise you, or did you expect to see more or less the same thing as this? Please, I'd love to discuss this...




PS. Well, in terms of possible errors/mistakes... I cannot say that I did it flawlessly, but it was a decent experiment, I don't think there are huge deceiving errors here.

 

[futile1981]

It WILL drop below the limit, unless you are in a very hot room! As said above, it dropped by 2 deg C when I tested (causing an average error of 1 deg C). Much more than the standard margin of 0.15 deg C, and enough to cause clearly visible problems when not taken into account. The agitation causes more heat transfer through the plastic. Plastic tank is not a proper heat insulator. It has a large surface area.

But this is not a real problem as you can compensate this by using higher starting point. This is probably the easiest way to do C-41, and while not perfectly repeatable, it can be very close to a good process.

If your room temperature varies a lot, you need to repeat the test for different room temperatures. I would say it is quite different for 20 deg C than for 28 deg C!

My experiment totally supports your point, yes, it does drop, and WAY beyond the 'optimal' range! You're right!

 

[Photo Engineer]

This type of test has been run and reported by others on APUG. This is exactly why it is recommended that you use at least 2 prewet steps of 100F water to temper your "system" before starting development.

PE

 

[stefan4u]

where is the Problem now?

I suggested you a prolonged prewarm or a double prewash and increasing the temp a bit to about 102 °F, if needed.
Than you will be fine.
You see by your own experiments where the benefits are...

Regards,
Stefan

 

[hrst]

To summarize, the largest part of the drop happens during the "development" time. It is the most crucial thing. This is why water bath is usually used, but you can use the averaging technique too if you don't want to mess with water.

Then, the second largest part of the drop is caused by the lack of prewash. Now, there is a difference between rotary and traditional agitation schemes because of the water volume used. You report 0.5 deg C difference between no prewash and one prewash; if this was a rotary process, the water volume would be half of yours and, hence, the drop would be at least 1.0 deg C. And, as you said, you did not have film in there. It could account for another 0.1 or 0.2 deg C. Note that having or not having film does not affect the drop during the development, only the prewash drop.

In a rotary process with minimum amount of chemicals, first prewash step brings the film at about 2 deg C from the aim, and the second one brings it at about 0.2 deg C from the aim (this is an approximation). Logically, third one would be 0.02 deg C off . Anyway, if there is no "second prewash", then the developer will be 0.2 deg C off. With your higher volume of water, this would probably be 0.1 deg C and become meaningless. Nevertheless, it is so easy to just do 2-step prewash that there is no reason to skip it.

However, your problem indeed was mostly in the cooling DURING the processing, and only secondly in the lack of prewash. Fixing those problems, and then adding a second prewash stage is for making the process PERFECT !

All this is enough to explain the contrast difference you can see by your eyes from the negative. But let's not forget that you might still be having the blix problem at the same time. I doubt even a severe underdevelopment by a drift of 2-4 deg C would not cause any significant difference in the Dmin ("mask") color.