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Thursday, February 16, 2012

I have got CD4

According to the advise of a faithful commenter, I ordered CD4 from a supplier in Germany and it arrived today. So, the next step will be testing the developer made of raw substances that one can buy. These substances are: CD4, Coffee, Soda and lemon juice.


First of all I will prepare a 5% solution of CD4 in order to avoid contact with the powder that is not so healty. Well, I can also prepare solutions of the other components, solutions are always better to handle than powder, also because you will not be weighting but measuring liquids which is easier.

So, be pacient while I prepare a new C41 developing kit, I need some amber bottles and other bottles that I can buy at the next Pharmacy. Bye...

7 comments:

ErikP said...

Best of luck to you!

H. Sousa said...

Thank you! I am still waiting for the pH meter I ordered at ebay to start the hard work. Meanwhile I may post some pictures with my homemade developing kit.

Trond Solem said...

Best of luck, but when you introduce any other developing agen than CD4, it will develop some of the silver, and you will get coarse grain because some of the exposed silver is developed by the cd4, and generates components to activate the dyes in the film, but also some of the silver is developed by the competing developing agent, and it will NOT generate the correct byproducts to activate the dyes, and you will get coarse grain.

The fact that you get increased acitivity of the cd4 when using coffe in the developer is related to superadditivity.
The developing agents, cd4 and the active part in coffe is working together to give to overall more activity, but it will still cause some of the silver to be developed by the developing agent in the coffe, and that part of the activity will not give you colors.
To get good colors without the coarse grain, you can't have any competing developing agent in your mix. That means, loose the coffe.

It can't be done with caffenol or another developing agent besides CD4.

Sorry to give you this message, but I feel that it is better to give you this hard message now before you use more money and effort in a work that isn't going to be any success.

A better and more intersting project is to make the c-41 process work at lower temperatures than 38c.

A starter point is that you will need about 5g/L of cd4.
You will have to soften the emulsion at your selected temperature to the level of the c-41 developer at 38c.
The pH of the c-41 developer is about 10.0.
You may have to exceed that to soften the emulsion to the same level, but it can be done by including other chemicals.
The reason for this is that the film is built up of three layers, and the developer reaches the lower layer quite a time after it reaches the upper layer. If the developing time for each layer is incorrect, the colors are twisted. You may correct the highlights in photoshop, but the mid-tones and shadows doesn't have the same color offset as the highlight's and correcting it is close to impossible.

Keep up experimenting, but please direct your efforts to something that may be a success. Using caffenol as a base for a color developer is futile.

Think of it this way.
You and your friend is going to colour a picture that is divied in small squares.

You have a set of crayons whith all the colors that is available in the world (a cd4 developer). Your friend has just white (caffenol, which can't create colors).
You colour a random square each in turns.
What will the final picture be?

IN this case it is better to work alone. Any help is just going to get all the squares in the picture colured in a shorter time, but the result is going to be inferior to what you can acomplish alone.

Trond

H. Sousa said...

Trond Solem, thank you for the explanation you gave. There is a point on witch I would like to hear your opinion: what about the difference between coffee and CD4 developing times? Coffee is a very weak developer, it takes alone some 45 minutes to develop silver and CD4 does it much faster when combined with the right stuff.
What I really liked was to find a color developer other than a synthesized stuff, something like coffee, tea, chocolate, etc.. Difficult, but not impossible. Just a question of keeping trying.
A color developer at room temperature is something very good but more adequate for a chemistry skilled person. I am not, I am a curious.

Trond Solem said...

The dyes in the film lacks only one common chemical to become a true dye. This chemical is a intended byproduct of developing silver with the CD4 developer.
I don't know any other developer that produces this chemical than the real CD4.
Cd3 produces nearly the same, but not exactly the right stuff, so the colours will be incorrect.

CD4 uses 3.5 minutes to develop a c-41 film at 38c. This calculates to about 15 minutes at 20c.
The main point is that you can't have any oter developing agent working together with the cd4, because this will develop random parts of the image with no chemical to acticate the dyes in the film at that point in the emulsion. When you bleach out the silver, the result is no color in that point, and the small patch is black.

Even if the synergi between caffenol and CD4 results in a more active developer, it still results in less colour generated in the film layers.

The only way to go is to use ONLY Cd4 and try to soften the emulsion to enable correct development of the three layers in relation to each others.
The bottom layers development in relation to each others may be controlled by pH or another way to control the swelling of the gelatine in the emulsion.
The development in the upper two layers may be adjusted in relation to each others by adjusting the amount of potassium bromide in the developer.
There is a catch here. Increasing the pH increaeses the overall activity of the developer and will affect de development of the upper layer.
Adding potassium broimide will affect development of all layers.

The only way to get a 100% perfect result is to use the 100% correct C41 developer recipe at 100F for the correct time.

Otherwise, you are on your own. :-)

H. Sousa said...

«The dyes in the film lacks only one common chemical to become a true dye. This chemical is a intended byproduct of developing silver with the CD4 developer.
I don't know any other developer that produces this chemical than the real CD4.
Cd3 produces nearly the same, but not exactly the right stuff, so the colours will be incorrect.»

Well, this is for me very challenging. Nobody else discovered a common substance that may be used to develop color negatives. But I already found references to Rodinal as a weak color developer and the that the color developers will not use CD-4 anymore, it will be replaced with another aromatic compound less dangerous for the health.

This substitute of CD-4 I am looking for may have disadvantages but, like coffee at the beginning, will only be used by experimenters that will try to make it better and better.

I will try developing at room temperature, as you pretend. Before, I never trusted me developing color, I was only developing B&W and I used for that the correction curves for room temperature. Now, after I started developing color, the temperature problem is less problem for me, we can live with it. Before I started, I also discovered this:
http://www.largeformatphotography.info/forum/archive/index.php/t-27067.html

man of constant sorrow said...

Hello!
Coul You please tell me where have You order CD4 as i am looking all over internet for CD4 in Europe and no result.
Thanks!