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Wednesday, August 16, 2017

Homemade gravity shutter

It is very easy to make a pinhole camera. But if we want to make a film camera with scars means, the more complicated part is, obviously, the shutter. I already made some rudimentary shutters using rubbers, wood and aluminum plates, without a concrete project. There are several types of shutters, see here. First of all I wanted to make a simple one, and this time I decided to plan it more in detail.


It is a single leaf shutter with 3 mouvable partes. The leaf, the catch mecanism that keeps the leaf covering the hole and the trigger that will push the leaf when it is released by the catch.

It uses two springs that I took from used ballpoint pens. Afer finishing the project I realized that another piece was needed to keep the leaf close to the square wooden base, whose dimensions are 5,7 x 5,7 cm. Also the hole resulted a little too large, due to the file I used to enlarge it, after drilling a a smaller hole with a home driller.

The next time, I will know more about these problems and maybe it will work better.
  

video

Wednesday, July 26, 2017

Salt as a fixer is spreading

As soon as March 2012, I rediscovered salt as a possible alternative to known thiosulfates fixers.

A 300g/l solution of salt will fix normal B&W films in about 24 hours.

After that date, I started a series of tests in order to make the salt fixer faster.

I came to the conclusion that adding 2ml/liter of a 5% solution of household ammonia to the salt fixer, the time is reduced to as few as 2 hours. In this recipe I also included 2g/l of Potassium Bromide which also contributes to the speeding of the salt fixer. But it may be left away, if time may be longer than 2 hours, let us say 4 hours. Also Potassium Bromide is not a household stuff and this is actually the aim of the thing, no need of expensive products and hard to get!

It is already 5 years ago that I published the 'finding' and slowly this is spreading away.

Early recognized by the Caffenol Master Reinhold, that promoted some discussions about it in forums,  I am glad to see that my modest contribute to homemade film development is beeing announced here and there. I found it today at the fine blog of Profesora G. J. Yukavetsky.

My compliments and special thanks!

Thursday, July 13, 2017

Dignan 2-bath and Betadine

My last modification of the Dignan 2-bath developer in order to get better results, at room temperature, is as follows:

Bath A

500 ml water
9 g Sodium Sulfite
1 g Potassium Metabisulfite
11 g CD4
Water to make 1 liter

pH should be acid
Time duration: 10 minutes (or more)
Note: Keep bath A in a dark bottle to prevent oxidation and reusage

Bath B

500 ml water
25 g Potassium Carbonate
0,6g Potassium Bromide
Water to make 1 liter.

pH is aimed to be about 11.
Time duration: 10 minutes or longer with constant (non stop) agitation for less grain.
Bath B may be one shot or reusable. No rinse or wash between bath A and B.

After bath B, a stop bath with 40ml of Vinegar per liter water is good to prevent basic contamination of the bleach bath and fixer.

And now, which bleach bath is suitable? Ferric(III)-Ammonium EDTA based bleach is good and Ammonium Thiosulfate as fixer is also a good option. But there are some more alternatives like Ferricyanide and Copper Sulfate & Salt for the bleach and Sodium Thiosulfate (Hypo) for fixer.

What only few people know is that Povidone-Iodine (sold under the brand Betadine) may also be used as bleach. Using a 10% solution of Povidone-Iodine, it takes about one hour to act. Like other bleach baths, it also needs aeration to work better.

Some examples of photos developed with the modified Dignan 2-bath as above, bleached with Betadine and fixed with Sodium Thiosulfate based fixer. The fixer also needs much more time to act, also one hour.






Conclusion: Betadine (Povidone-Iodine) works very well (IR scanning didn't show any remaining silver) and Sodium Thiosulfate works well too, both need much more time than regular accepted bleach and fix baths.

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!


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.