Monday, June 19, 2017

Parodinal, another alternative

Parodinal is a clone of the famous developer Rodinal, from AGFA. It has a very long shelf life and can be used in concentrations from 1:10 to 1:200. However, when diluted it should be used in the next hours. It may be used for paper in the strongest concentrations and for film or plates for the more diluted baths.

Taking this formula as starting point, let us translate it to 500 ml, doubling the contents:

30 g Paracetamol
100 g Sodium Sulfite
40 g Sodium Hydroxide

I had many difficulties to get Sodium Sulfite at local suppliers. So, I started thinking about alternatives using Potassium Metabisulfite instead. Using a chemical balance calculator like this one, I realized that following equation is valid:

K2S2O5+NaOH = SO3K2 + SO3Na2+H2O

The first term is Potassium Metabisulfite and Sodium Hydroxide and the second is Sodium and Potassium Sulfite and some water.

From 80 g Potassium Metabisulfite and about  30 g Sodium Hydroxide, one gets about 100 g Sulfites that may replace the 100 g Sodium Sulfite given in the formula above. This leads to following new recipe:

30 g Paracetamol
80 g Potassium Metabisulfite
70 g (40+30) Sodium Hydroxide

It works very like Rodinal, same times and dilutions.

Following photos were made with an Agfa Clack camera, using Ilford Delta 100, developed with this last recipe in dilution 1:100 for 60 minutes in stand development:





Saturday, June 3, 2017

More coffee, please!

Like I promised, I changed the last universal developer recipe like this:

800 ml water
3 g Potassium Metabisulfite
6 g CD4 (color developer for C-41)
30 g Soluble coffee
35 g Potassium Carbonate
1,5 g Potassium Bromide
Water to make 1 Liter

I developed for 12 minutes with constant agitation at room temperature, bleached and fixed. Perhaps I could have done 15 minutes too, the results would not be so different, I think.

Because coffee is acidic I raised slightly the Potassium Carbonate content and I got evidently better negatives and the difference can be appreciated by sight.

One of the 8 photos made with an Agfa Clack and expired Fujicolor Superia 100:






Tuesday, May 30, 2017

After one year...

One year ago I had to stop my experiments. I am restarting, and I have new results about developing color with coffee... and CD4!

I had, after many not convincing results, established a formula for my universal developer with wich I got some good pictures, color and B&W:

800 ml water
3 g Potassium Metabisulfite
6 g CD4 (color developer for C-41)
20 g Soluble coffee
30 g Potassium Carbonate
1,5 g Potassium Bromide
Water to make 1 Liter

Develop for 15 minutes for both C-41 and B&W at room temperature with constante agitation.

I never had a confirmation off the need of coffee in this recipe. So, I tried to reduce the content of coffee and increase the content of the color developer CD4. But the results showed, clearly, that the coffee content is important. Some people argued with me that beeing coffee a B&W developer, it would compete with CD4, stilling silver that would contribute to more color when developed by CD4.

But the theory was not confirmed by the praxis. Here is a photo developed with the recipe above:

Photo developed with Caffenolcolor
And here is a photo developed with 10g/liter of CD4 and only 10g/liter of coffee:

Less coffee and more CD4
It is obvious that the first photo is more color saturated than the second, and perahps the coffee content should be even increased...

Have a nice time with coffee!