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Saturday, March 29, 2014

Dignan's 2-bath developer

I have been using Dignan's 2-bath developer with some success. The pictures are quite different from a normal C-41 process, but nice. See, for instance, this one:

Dignan's 2-bath at room temperature

As is known, color photography works with 3 sensitive layers, each of them sensible to one the main colors Red, Green, Blue, from which a color image is done. Yhe red sensitive layer will give the color Cyan in the negative film, the green sensitive laer will give Magenta and the Blue sensitive will give yellow. Cyan, Magenta and Yellow are considered the inverted colors of Red, Green, Blue. So, the negative color image should have only diffrent amounts of Cyan, Magenta and Yellow and when positivated give a normal RGB positive image.

Dignan's 2-bath developer consists in soaking the fim in a solution of CD-4. the dye developer and then let it work in the second bath of Potassium or Sodium Carbonate.

My pictures, developed with this developer at room temperature present color shifts, what means that the dyes didn't get their CMY values. For instance the shift to Magenta instead of red means that the Cyan dye coupler became greenish. And so on.

What is the main difference between normal C41 process and Dignan's? The temperature! So, we must assume that the temperature will calibrate the CMY dyes in the film.

So I decided to use temperature in the second bath, around 40ºC. The results became more satisfactory, what colors shift are concerned. Look at this example, with no color correction via software:

Dignan's 2-bath using temperature


Tuesday, March 25, 2014

Orange juice pure

With more or less the same philosophy I followed for Coffee Black, a only coffee developer with 20g/l of coffee and pH=11,4, I tried to make the same with Vit.C. The first time I diluted some 10g/l Vit.C and tried to rise its pH to 12 what I succeeded using sodium hydroxide. The second time I found out that I was very lucky in the first time. It is not that easy to achieve pH=12, it will be more or less than 12. Back to internet pool searching for other's experiences with Vit C. And here I found the solution to my problem: Patrick Gainer. Patrick advices us to join Vit.C in the buffer solution and not the contrary.

So, I started by making a buffer solution of pH=12 with sodium carbonate only (50g/l is enough). Then I joined Vit C until I see that the pH will strat to drop from 12. Stop! 10 g Vit. C. I may resume then the recipe as follows:

700ml water
50g Sodium Carbonate
5g Vit. C
Water to make 1 liter

It is a one-shot developer like others I described here. Development time is also 60 minutes and gives no fog and little grain. The film will not have deep blacks, looks much less contrasty than Coffee Black and shows that Vit. C can work together with coffee to make general purpose developers.







Tuesday, March 18, 2014

Caffenol Solo or Caffenol Alone or Black Caffenol

In a recent discussion in Flickr, someone wanted to give up from caffenol because he only got dense negatives, hard to extract an image. I entered the discussion later and started a seiries of experiments using just coffee as developing agent and just Sodium Hydroxide as alkali.

The results are very nice, no fog, no stain, completely nice developed negatives using only 2 components. This is, maybe, not so often, I only remenber a developer using 2 components, the Kodak 23, which formula is:

7,5 g metol
100 g Sodium Sulfite
Water to make 1 liter

This new developer I prepared by the scientific method (trial-and-error), may be prepared as follows:

750 ml water
15 g soluble coffee
Sodium Hydroxide (or Carbonate) q.b. to achieve pH=11,4
Water to make 1 liter
Properties of the developer: it is important that pH=11,4 or maybe a little higher. Too high pH will produce fog, too little will take too long and below 11 no development takes place. It is a one-shot developer. Reuse gave bad result even with pH=11,4. You may put more coffee and more alkali to accelerate the process but keep pH=11.4. I needed 60 minutes with the above formula.

And here are some photos made with my Minolta Maxxum 7000 using Polypan F film:






Monday, March 17, 2014

I have been absent so long...

I am sorry, time is not enough for Facebook, Flickr, Ipernity and making photos and developing and scanning and posting and also write about the work done.

So, if nothing new has been tested or experimented, normaly the blog stays without changes.

But you are lucky that I have made more advances and I have a B&W developer recipe, very simple, and lots of photos to show, both B&W and color. In color I want to start a series of experiments around the Dignan's 2-bath developer in order to establish a chart of parameters like pH and temperature and what we may obtain of it.

I have a technical problem to solve but maybe someone knows how it works. I want to classify the color negatives I produce according to their state of development, if they are weak or strong and the color shift, etc. Is there a software that combined with the scanner cann measure a color negative?