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:

Kristoffer Rae 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

Jacob Harrison 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!