Selecting a good C-41 kit / Separating blix into bleach & fixer.

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dcy

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It also might be that you need the water as well in order for the mixture to have any longevity. Water is, of course, a chemical too.
And packaging, shipping and storing water costs money.

Sometimes I wonder why our society spends so much money storing water and moving it around in trucks when it literally comes out of a numerous pipes around my home. My toilet cleaner is 97.6% water and 2.4% bleach. You'd think the default would be to buy a concentrate and add water.
 

Spektrum

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There are several reasons for this:
1. Gigantomania – I'm not sure if this is the correct term for this type of purchasing preference among shoppers. People buy with their eyes. Looking at a store shelf, they choose a product that appears to contain more, based on their visual assessment. For example, when looking at other products in a 1-liter package, they will likely choose these products over a highly concentrated product in a tiny bottle, even though it's clearly labeled a concentrate.

2. Purchasing habits – for years, people have been buying this product in larger packaging (for example, a 1-liter bottle). If a manufacturer intends to switch to concentrates, they must consider that potential buyers will perceive the product as a reduced quantity at the same price. They will feel cheated and may abandon the brand altogether. It's too much of a risk for the manufacturer.

3. Safety - A highly concentrated product can be very dangerous. For example, it can be highly corrosive and pose a risk of burns. However, the same product heavily diluted with water poses no such hazard.
 

gbroadbridge

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You may want to see if the Japan manufactured Ilfocolor C41 2.5l kit is available.

It specifies 12 weeks life for opened CD with 24 weeks for the rest.

I just mix up the full 2.5l and divide it into two lots of 1.25l. It seems to last forever - at least I've stretched the first 1.25l out to over 9 months.

The datasheet suggests mixing up as much as you need and storing the stock solutions in the orginal bottles until needed.
 
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dcy

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A manufacturer can make two products. Clorox does sell a concentrate. I ordered one after I sent in my post. I'd just never seen it in the store shelf.

3. Safety - A highly concentrated product can be very dangerous. For example, it can be highly corrosive and pose a risk of burns. However, the same product heavily diluted with water poses no such hazard.

Again. Concentrates do exist. The interesting part is that the market often doesn't prefer them. Don't forget all the other products that are not dangerous and are often sold with water that you could add yourself. --- Soap. Shampoo. Laundry detergent. I buy powder detergent, but I admit I buy shampoo with water pre-inserted even though shampoo bars exist.
 

Wayne

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Some people have reported mixing and freezing the developer for years with good results.
 

Koakashii

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I’ve just tried the “new” Kodak c41 2.5L kit from cinestill’s site and since I’ve only used cinestills c41 kit and Rollei’s kit I can say the Kodak kit is from what I see able to produce way more neutral based negatives very print ready and scanning ready compared to cinestill and rollei and it has to do with the separate bleach and fix and overall more consistent quality than other kits
 
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dcy

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I would recommend making up all 2.5 L and splitting it up into 5 full 500ml bottles. Or something similar. You can develop 3 or 4 films in each 500 mL then toss.

Yep, that's what I do. Works great. The developer keeps ages that way.

Quick follow-up... What about the bleach and fixer?

My general understanding is that bleach and fixer never go bad. The kit instructions (link) say that the concentrates and working solutions last 24 weeks, which is long enough, but it's not forever.

Would I be right in thinking that with the bleach & fixer, I don't need to worry about splitting them into 500 mL increments, filling the bottle to the top, or making the whole solution at once like you recommended for the developer?

I am going to order the kit today. I haven't yet accumulated the first batch of 4 color rolls but I'll be there soon (it takes me a while; I mostly shoot B&W). Right now I'm ordering enough containers to store all this chemistry. --- 2.5L x developer + bleach + fixer = 7.5L of chems!
 

mshchem

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Once exposed to air the fixer concentrate can precipitate sulfur and decompose. Bleach in my experience hasn't been a problem. Regular rapid fixer (no hardener) film strength will work fine.
 

koraks

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What about the bleach and fixer?
What @mshchem says above, although I've personally never had Fuji CN16/C41 Negacolor RA N3 fixer go bad, not even in a half-full jug of concentrate. It's a very robust product. C41 bleach just doesn't die.
Btw, I use the color fixer for B&W (film + paper) as well.
 
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dcy

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That would be minilab chemistry, right? The only times I've seen C-41 fixer sold by itself has been in large units and the description specifically mentions minilabs.


I've read conflicting information about using B&W fixers for color. Some posts in other forums have said that the acidity of many B&W fixers can damage the colour dyes. If acidity is an issue, one can buy neutral pH B&W fixers.
 

koraks

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That would be minilab chemistry, right?

Correct; Fuji Negacolor RA N3.

I've read conflicting information about using B&W fixers for color. Some posts in other forums have said that the acidity of many B&W fixers can damage the colour dyes. If acidity is an issue, one can buy neutral pH B&W fixers.
If you read well, you notice the accounts are not necessarily conflicting. They're complementary and if you add the nuances, they turn out to be both correct. If you leave the dyes in CN film in a very acidic state (as during fixing in an acidic fixer), they lose part or all of their color (the go into a 'leuco' state). This is a reversible process (so it's not 'damage'). On modern color film, if you put the film in an acidic bath, you'll see the colors fade to an extent. If you then wash the film in water, you'll see the color return. Modern CN film can be fixed in an acidic fixer for all I know, provided you wash the film afterwards so the acidity is removed. It's possible that the dyes in very old CN films (pre-1990) might not revert to their colored state - mind you, I'm not sure on this and I expect that really, they will. I can't guarantee it.

This means that in a CN process that involves little or no wash (e.g. a minilab), an acidic fixer could be a problem if the acidity remains in the film due to the brief or absent wash (e.g. only a stabilizer bath), as this will leave the dyes in a partially de-colored state. In a typical home process where you wash the film after fixing, there shouldn't be a problem.

And indeed, as you said, if you want to be sure, you can bring an acidic fixer to a pH neutral by adding e.g. potassium or sodium hydroxide. Use test strips or a pH meter to verify you've hit neutral.
 
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