Sunday, May 29, 2016

Another approach to Dignan's 2-bath developer for C-41

What seduced me with Dignan's divided developer was the absence of time and temperature control when doing C-41 at home, without expensive equipment.

I am using the method for quite a while now, but I still have some in-satisfaction about colour shifts, grain, shelf life, etc..

I already tried to solve colour shifts using different recipes for bath B, decreasing or increasing pH. The grain has been always there, no matter how I agitate or not. Shelf life was 1 month for bath A and pictures were becaming weaker and weaker.

Let me remind you of the composition of bath A:

1 g of Sodium Bisulfite
9 g of Sodium Sulfite
11 g CD4
Water to - 1 liter

I couldn't get Sodium Bisulfite, but I read somewhere that Metabisulfite in 1:1 proportion would do the same. So I used 1g/l of Potassium Metabisulfite.

I tried to use more Potassium Metabisulfite, 2g/l, to prolong the shelf live and indeed, it worked. I could use the same batch of bath A during 6 months with little changes that I compensated with longer bath B until 1 hour.

The use of more Potassium Metabisulfite seems to require longer bath B anyway.

The last insight I had about the divided C-41 developer was this one: Why not helping the second bath with a little of bath A in it? This could have as result a better overall development and, who knows, better negatives?

In fact, I started using 20ml/l of bath A in bath B and then increasing to 50ml/l. Yes, better colours and better density of the negatives. And with constant agitation I had much less grain than before.

But, and this could cut to zero the advantages of Dignan 2-bath developer, if we need 50 ml of bath A for each film, after 20 films we spent 1000 ml that would also have developed 20 films without split development.

But no, bath B with 50ml/l of bath A may develop 2, 3 or more films, so making the process very attractive.








6 comments:

Unknown said...

Absolutely in love with your results! This process is very inspiring and I love the potential in this developer. Where do you get your chemicals? I'm having a hard time finding cd4 online

Henrique Sousa said...

Thanks for commenting. CD4 may be purchased online via Moersch Chemie, the complete adresse wher you may download the presilist http://www.moersch-photochemie.de/content/rohchemie

Anonymous said...

Hi, Henrique. I have just recently discovered your blog and it is a wonderful source! I live in Brazil and over here there is not a single soul in the market who can tell what is CD4! Are there other names for it? Thank you and congratulations for your great work!
Julio Cesar
São Paulo- BR

Photo-60 said...

Really awesome blog. Your blog is really useful for me.

professional film developing

home movies to dvd

Robert Wilson said...

Again, inspiring.
I'm in the very early stages of attempting a monobath c41 process.

Henrique Sousa said...

Hi, Robert Wilson, That sounds really interesting! I am curious!