C41 Bleach

[koraks]

Now I read this thread. Oh my gawd, no way.

I'm sorry you got this impression. IMO the central message of this thread is "don't sweat it and give it a go". The only thing "complicating" matters is that there's several ways to get it right!

 

[Radost]

With lack of availability of my normal C41 developing kits I changed over to Fuji Hunt 5 litre kits. The stability of the developer is superb in the concentrates but the Bleach bath working solution is a different matter The developer is made up each time I need to process a film but the bleach I make up as a half litre working solution. I have just ruined 3 x 35mm x 36 exp films because the bleach appears to have become exhausted quicker than what I would have normally expected. Am I being over optimistic as to how many films that can be bleached in half a litre of bleach working solution. The fixer stage appears to be working as normal (Seperate bleach and fixer).
In the initial mix I have processed 7 films 635mm and 1 x 120.

On the upside, the colour rendering on previous films was superb.

I say it is the bleach stage, because I re-bleached them in a fresh dilution and there was a slight improvement, but not enough to print normally, although they will scan and can be corrected using photoshop. Even the scans come out as having a strong reddish/orange tint.

Any thoughts?

get a well developed black and white film Especially if it is exposed to light.
Run your normal c41 bleach wash fix wash at 100F
If all the sliver is gone you bleach is good.
Shake the bleach and make sure it has a portent smell.
I was told 10ml of 3% hydrogen peroxide will reactivate it . I have not tried it.
I made the mistake to close seal my Fuji hunt bleach with heavy gas on top,
4 liters almost went hell

 

[koraks]

get a well developed black and white film Especially if it is exposed to light.
Run your normal c41 bleach wash fix wash at 100F
If all the sliver is gone you bleach is good.

This test will certainly show it the bleach is good, but if it fails, it doesn't mean the bleach is bad per se. This is because a B&W film has far more silver in it than any color film does, so it will take longer to bleach out a B&W film.
Admittedly, a color bleach in good condition and within regular C41 parameters will have so much excess capacity that it will likely reliably bleach even a B&W film.

 

[Formulahunter]

is there a way to check the Bromide concentration? Otherwise how can you tell how much Bromide to add when doing replenishement? I have read, it is possible to just add new Brode when its used.

 

[koraks]

is there a way to check the Bromide concentration?

Not a practical/feasible way, no.

In a properly replenished bleach no bromide needs to be added. If you want to McGyver-replenish through aeration, I'd just wing it with the bromide addition. It's not very critical as long as there's enough of it. Maybe a teaspoon of potassium bromide every dozen of films or so.

 

[Radost]

Is Fuji and Kodak bleach the same. I would love to replenish my Fuji bleach.

 

[koraks]

Is Fuji and Kodak bleach the same. I would love to replenish my Fuji bleach.

Probably not exactly the same, but in all likelihood mixing them together will work perfectly fine.

 

[Radost]

Probably not exactly the same, but in all likelihood mixing them together will work perfectly fine.

I was asking so I can come up with replenishment

 

[koraks]

I understand. It will likely work. Use the replenishment rate of the product you'll use as the replenisher.

 

[foc]

Have a look at page 5 in this Fuji document, it gives the replenishment rates for the different C41 chemicals and the difference between the C41 range of chemicals, the CN16Q and CN16L (low replenishment).

https://www.tmax100.com/photo/pdf/fujirepmix.pdf

 

[koraks]

it gives the replenishment rates for the different C41 chemicals

Not really, unless I'm missing it. This is a more appropriate source for the current CN16 chemistry: https://asset.fujifilm.com/www/au/files/2020-08/e2cba56652a6e4319704b5d7f2691d51/cn16lq_.pdf

Sadly, the online availability of Fuji documentation is hampered by their content management, which is rather diffuse, varies by region and the documentation often does not involve clear document dates or versions. Google tends to turn up relevant stuff with some effort, but it's kind of hit & miss.

 

[sillo]

Agreed, Fuji needs to do a better job with their documentation and product naming/numbering scheme. Kodak blows them out of the water in that realm.

 

[Radost]

Is hunt chemistry the same as cn16 or different?

 

[koraks]

Is hunt chemistry the same as cn16 or different?

Hunt is a specific production plant owned by Fuji, in Belgium. I assume they make CN16 chemistry as well.

 

[Radost]

Hunt is a specific production plant owned by Fuji, in Belgium. I assume they make CN16 chemistry as well.

It figures why Fuji hunt Chems are cheaper in Europe. .

 

[Formulahunter]

Hunt is a specific production plant owned by Fuji, in Belgium. I assume they make CN16 chemistry as well.

Hunt was a american chemical manufacturer, that had Plants in europe. Then it got bought by Fuji. they called that part of the Bussines Fuji hunt. In 2017 Heidelberg printing mashines took over a Part of that Bussines from Fuji, but idk if this takeover included the chemical manufacturing.

 

[koraks]

Hunt was a american chemical manufacturer, that had Plants in europe. Then it got bought by Fuji.

Indeed.

In 2017 Heidelberg printing mashines took over a Part of that Bussines from Fuji, but idk if this takeover included the chemical manufacturing.

Certainly not Fuji Hunt, which continues to be part of Fujifilm. Heidelberg purchased a specific part (one German and one Belgian plant, the latter in Kruibeke specifically) of Fujifilm that was manufacturing consumables specifically for the (offset) printing industry. It was/is unrelated to photo chemistry, which is still being manufactured under Fuji's management and ownership at the Sint Niklaas plant.