Hey everyone, i've been using this site for awhile now as a resource, but this is my first time posting. I've been developing my own 35mm film with the unicolor c41 kits and various b&w developers for awhile now. I recently acquired a 100' can of 35mm fuji eterna 500T for $30 and because it's ecn-2 process this sent me down the scratch mixing rabbit hole. I've been researching how to scratch mix the kodak ecn-2 formula to develop this film for the past few weeks and i'm almost ready to buy the required chemicals, but I have a few minor questions to ask before I buy them that I couldn't really find searching the forum; although I'm sure they've been discussed at length here.
My main question is with regards to storing these bulk powder chemicals. I'm assuming the powdered chemicals will be shipped within plastic bags and since i'm buying some of these raw chemicals in bulk when the formula only requires me to use 1-5 grams per batch I don't want them to go bad too fast. I know once mixed the shelf life of the chemistry drops dramatically, but for these powdered chemicals will simple amber colored mason jars be enough to prevent whatever oxidation or light-sensitive reactions that could potentially degrade them from occurring, or at least minimize them? I like to think that I shoot a lot of film, but when 1L of ecn-2 formula uses 4g's of CD-3 and the smallest amount I can buy is 100g of CD-3, I know that it's going to take me a long time to go through that supply even if I was using the developer as a one shot (although I don't plan to; i'd be happy with around 5 rolls per batch).
My next question is about the difference between using potassium and sodium "salts". I'm not a chemist so they may not even be called "salts", but i've seen a few formula's use potassium carbonate instead of sodium carbonate or potassium bromide instead of sodium bromide, etc. I've also seen a few posts around here saying that they were pretty much interchangeable and perform the same function in the formula, but that you still have to calculate how much to add or subtract when replacing one with the other. Does anybody have any resources for the lay man on the differences between these two and how to figure out how much to add or subtract when replacing one with the other? I'm only asking because the potassium versions seem to be cheaper, but if these sort of calculations are above a layman's head then i'll just stick to the formula's I find around here.
My third question is hopefully just a simple one: Most of these formula's are for mixing 1L batches at a time which is what i'll be mixing 99% of the time and then storing these working solutions for as long as I can (which, again, I realize won't be very long). But for the odd occasion when I want to do something weird and experimental for a single roll in my ~250mL stainless steel tank is calculating the necessary proportions as simple as dividing the 1L batch formula components by 4? In this scenario I would definitely be mixing chemistry for one-shot use. Or would it be better to just use 250mL of my 1L working solution?
My final question is about fixer. For b&w I use ilford rapid fixer; it's cheap, readily available and has never let me down. Can I use this for my ecn-2 or c41 scratch mixed developers? Or is it not a suitable replacement? The main ingredient in both the Kodak ecn-2 fixer formula and ilford's rapid fixer is ammonium thiosulfate, but the secondary ingredients are different.
Anyways, this site has been indispensable in building my confidence to do this and I plan on following the kodak ecn-2 formula as closely as one can and opting for the ferricyanide bleach. While sourcing the chemicals required for ecn-2 through artcraft and photographers forumlary i've also decided to get some raw c41 chemicals as well. With the unicolor kits only being $20 and considering that those kits are able to develop around 15-20 rolls comfortably through a 1L batch with acceptable (to me) results I'm not sure if scratch mixing c41 is more economical, but I like the idea of scratch mixing my own c41 and I like the general spirit of DIY that goes with scratch mixing so i might as well give it a shot as well.
Cheers!
My main question is with regards to storing these bulk powder chemicals. I'm assuming the powdered chemicals will be shipped within plastic bags and since i'm buying some of these raw chemicals in bulk when the formula only requires me to use 1-5 grams per batch I don't want them to go bad too fast. I know once mixed the shelf life of the chemistry drops dramatically, but for these powdered chemicals will simple amber colored mason jars be enough to prevent whatever oxidation or light-sensitive reactions that could potentially degrade them from occurring, or at least minimize them? I like to think that I shoot a lot of film, but when 1L of ecn-2 formula uses 4g's of CD-3 and the smallest amount I can buy is 100g of CD-3, I know that it's going to take me a long time to go through that supply even if I was using the developer as a one shot (although I don't plan to; i'd be happy with around 5 rolls per batch).
My next question is about the difference between using potassium and sodium "salts". I'm not a chemist so they may not even be called "salts", but i've seen a few formula's use potassium carbonate instead of sodium carbonate or potassium bromide instead of sodium bromide, etc. I've also seen a few posts around here saying that they were pretty much interchangeable and perform the same function in the formula, but that you still have to calculate how much to add or subtract when replacing one with the other. Does anybody have any resources for the lay man on the differences between these two and how to figure out how much to add or subtract when replacing one with the other? I'm only asking because the potassium versions seem to be cheaper, but if these sort of calculations are above a layman's head then i'll just stick to the formula's I find around here.
My third question is hopefully just a simple one: Most of these formula's are for mixing 1L batches at a time which is what i'll be mixing 99% of the time and then storing these working solutions for as long as I can (which, again, I realize won't be very long). But for the odd occasion when I want to do something weird and experimental for a single roll in my ~250mL stainless steel tank is calculating the necessary proportions as simple as dividing the 1L batch formula components by 4? In this scenario I would definitely be mixing chemistry for one-shot use. Or would it be better to just use 250mL of my 1L working solution?
My final question is about fixer. For b&w I use ilford rapid fixer; it's cheap, readily available and has never let me down. Can I use this for my ecn-2 or c41 scratch mixed developers? Or is it not a suitable replacement? The main ingredient in both the Kodak ecn-2 fixer formula and ilford's rapid fixer is ammonium thiosulfate, but the secondary ingredients are different.
Anyways, this site has been indispensable in building my confidence to do this and I plan on following the kodak ecn-2 formula as closely as one can and opting for the ferricyanide bleach. While sourcing the chemicals required for ecn-2 through artcraft and photographers forumlary i've also decided to get some raw c41 chemicals as well. With the unicolor kits only being $20 and considering that those kits are able to develop around 15-20 rolls comfortably through a 1L batch with acceptable (to me) results I'm not sure if scratch mixing c41 is more economical, but I like the idea of scratch mixing my own c41 and I like the general spirit of DIY that goes with scratch mixing so i might as well give it a shot as well.
Cheers!