Cybertrash
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Hello all,
I've noticed that almost all images from C41 negatives that I have developed by myself have some sort of magenta or red cast to them on the resulting positive. So far I haven't been able to do actually print them, but I am fairly confident that it is the development process where something goes wrong, as I've scanned self-developed negatives and lab-developed negatives right after another with the exact same settings, just to rule that out as a variable (else I'd be posting in the Hybrid forum).
I currently develop using a Jobo CPE2 with a lift and the Jobo 6-bath C41 kit, using their recommended process, I have also been re-using the chemistry as advised by them and I store the working solutions in brown glass bottles with and I use these vacuvin stoppers to pump out extra air from the bottles. However after going through a number of developed rolls it appears as if the issue is apparent regardless of the age of the working solution.
For measuring the temperature I use an Adox dial thermometer (seems to have been discontinued, so there's no English description on their website, hopefully it's clear enough what it is anyway). Typically the water bath in the Jobo will ned to be set a little higher than 38°C in order for the solutions in the bottles to reach the desired temperature.
Looking at the negatives themselves it is quite hard to tell the difference with the naked eye, here the left strip is lab-developed and the right one is home-developed and to me it appears as if the base of the right strip is slightly blue or purple than the left one:
Bringing them into the computer the difference is more notable (forgive the slight trespassing into hybird territory here), this time the lab-developed negative on the right and the home-developed negative on the left. To me it looks like the home-developed negative has a blue cast to the base, and it becomes very apparent in the colour of the trees.
I think in the end, when inverted, this has the effect of adding a red or magenta cast to the resutling positive, which is quite troublesome to colour correct. I would imagine that this might be an even larger problem if I were to do RA4 prints of these.
Does anyone know what might be the cause of this issue? I have tried finding information online, and I've seen some suggestions that exhausted developer might cause something like this, but since I've developed using newly mixed developer and still gotten these results I'm not conviced that is the case here.
Ideally I would get some process control strips, but if I've understood things correctly you also need a colour densitometer to use these, which I do not own.
Could I have issues mixing up the chemicals? I've split the initial 2.5L batch into several 1l batches according to the Jobo instructions, and I mix using graduated cylinders which I would expect to be accurate enough. Or could it be a temperature issue? Or light leaks? Any advice would be appreciated.
Thanks!
I've noticed that almost all images from C41 negatives that I have developed by myself have some sort of magenta or red cast to them on the resulting positive. So far I haven't been able to do actually print them, but I am fairly confident that it is the development process where something goes wrong, as I've scanned self-developed negatives and lab-developed negatives right after another with the exact same settings, just to rule that out as a variable (else I'd be posting in the Hybrid forum).
I currently develop using a Jobo CPE2 with a lift and the Jobo 6-bath C41 kit, using their recommended process, I have also been re-using the chemistry as advised by them and I store the working solutions in brown glass bottles with and I use these vacuvin stoppers to pump out extra air from the bottles. However after going through a number of developed rolls it appears as if the issue is apparent regardless of the age of the working solution.
For measuring the temperature I use an Adox dial thermometer (seems to have been discontinued, so there's no English description on their website, hopefully it's clear enough what it is anyway). Typically the water bath in the Jobo will ned to be set a little higher than 38°C in order for the solutions in the bottles to reach the desired temperature.
Looking at the negatives themselves it is quite hard to tell the difference with the naked eye, here the left strip is lab-developed and the right one is home-developed and to me it appears as if the base of the right strip is slightly blue or purple than the left one:
Bringing them into the computer the difference is more notable (forgive the slight trespassing into hybird territory here), this time the lab-developed negative on the right and the home-developed negative on the left. To me it looks like the home-developed negative has a blue cast to the base, and it becomes very apparent in the colour of the trees.
I think in the end, when inverted, this has the effect of adding a red or magenta cast to the resutling positive, which is quite troublesome to colour correct. I would imagine that this might be an even larger problem if I were to do RA4 prints of these.
Does anyone know what might be the cause of this issue? I have tried finding information online, and I've seen some suggestions that exhausted developer might cause something like this, but since I've developed using newly mixed developer and still gotten these results I'm not conviced that is the case here.
Ideally I would get some process control strips, but if I've understood things correctly you also need a colour densitometer to use these, which I do not own.
Could I have issues mixing up the chemicals? I've split the initial 2.5L batch into several 1l batches according to the Jobo instructions, and I mix using graduated cylinders which I would expect to be accurate enough. Or could it be a temperature issue? Or light leaks? Any advice would be appreciated.
Thanks!
