perfect development with Caffenol-C-L

2 posts belowyou can see the effects of different agitation. From extreme uneven development with stand development to a dramatic improvement with standard agitation. 

When adding the restrainer potassium bromide (KBr), we see perfect even develpment up to the reel covered borders - even with minimal agitation as shown here. With intension I made no proper black adjustment here to show the improvement in the clearest possible way. 

So here's my recommendation:

If you are satisfied with "regular" Caffenol-C like C-C-M, be happy. If you experiance uneven development, agitate more (you will have to adjust developing time). If still not satisfied use Caffenol-C-L. 

The benefit of C-C-L besides the 100% perfect even development are reduced grain and almost fog free negatives.

Caffenol-C-L will be my standard in the future.  My 100 g box of potassium bromide will last for a couple of films ;-) Caffenol-C-M will still be my standard as an easy to use and easy to get developer with enhanced film speed..

 So if you can get KBr for a resonable price in your country, buy it! You won't be disappointed.

Cheers - Reinhold

Caffenol-C-L

First results, Minolta X-300, 50mm Rokkor, orange filter, APX 100 in Caffenol-C-L

Recipe:

16 g/l washing soda waterfree, 10 g/l Vitamin-C, 40 g/l instant coffee, 1,5 g/l potassium bromide (KBr)

Use 1 - 2 gram/liter KBr, 1,5 seems to be a good idea. Do not use more than 2 g/l, it will restrain development too much up to blank negs.

40 minutes semi-stand development at 24 °C. Agitation first minute continuos, 3 inversions each at 2, 4 and 8 minutes, then let stand.

No fog, fine grain, perfect even development, about boxspeed.

Maybe some minor tweaks in the future, but looks fine so far. 

Maybe not everybody is able to get potassium bromide easily? I got it from my next door pharmacy. It's not toxic and environmentally safe with the used quantities.

Looks promising that C-C-L may also be good for high speed films.

Do not try (semi-)stand development without a restrainer like KBr -> agitation is the key! 

PS: I didn't use semi-stand development for another reason than comfort, I don't like shaking for half an hour. ;-)

Cheers - Reinhold

uneven development

 click on the picture for bigger size

 Some people report uneven development and/or disturbing fog. That effect appears almost always with classic (cubic crystals) emusions like Ilford PanF+ or Agfa APX 100. Not enough agitation is the cause. A drastic example is stand development with Caffenol-C, as you can see in the image above.

What is happening? Lets regard the left picture. Stand development makes it visible. Classic bw-emulsions contain a lot of silver-bromide, the silver is reduced by the developer to form the blacks, and the bromide is set free. Bromide is a strong restrainer, but without or too less agitation it sinks down in the tank and produces less development, marked with a red "x" in the left picture.Also below parts of high exposure more bromide is set free and causes streaks. Below the sprocket holes, less bromide is set free leading to stronger development. Finally the bromide accumulates at the bottom and there we find the least development and - the least fog!

In the right picture with regular agitation we see no eneven development or fog at all exept for the small upper and lower parts covered by the reel during development. The bromide is dispersed evenly and so we have a constant restraing effect over the whole area. The uncovered upper and lower borders are developed evenly  with low fog level, see the red "x"-es.

So agitation is the key for even development. Of course there is some remaining general fog,  but doesn't disturb because it is spread evenly over the whole film. If you get uneven development or disturbing fog, agitate more! Try the heavy agitation regime recommended f.e. for Xtol, 5 times in 5 seconds every 30 seconds. That's almost shaking! And reduce dev time when doing this! Time, temperature and agitation are closely related, keep that in mind always.

My trial with stand development was very revealing. It was done when experimenting with low-pH Caffenol-C. As the development times with low-pH will increase and I didn't want to shake the tank for 20 or 30 minutes, I gave stand development a try. With the shown faults. But - when adding the bromide in a good amount from the beginning as a separate agent, unevenness and fog will be gone! So stay tuned and await a new Caffenol-developer by me, it will be named Caffenol-C-L. Only a little bit of fine tuning necessary.  Compared to C-C-M it will have a bit film speed loss, but probably still boxspeed, finer grain and fog free even with stand development!

With "modern" medium speed films like Acros100 or Tmax100 things are different. They contain much less bromide and are much less fog sensitive and show perfect even development with C-C-M. Maybe C-C-L will also be recommended for high-speed films. So some things to do in the future, it doesn't get boring at all.

Time for a cup of coffee - cheers - Reinhold

first summary and why fog is good

Hi,

after more than 1 month here's my first summary. What happened? When starting this blog, I wanted to share my experiances with Caffenol-C as a high grade b/w-developer. made with household ingrediants. My approach is not experimental, I use it as any regular developer and it should produce outstanding results. Caffenol-C-M (CCM) does! You can make up your own mind by reading this blog, watching closely the displayed images or simply and best by doing yourself. If you are new to the Caffenol developement, I suggest you start with the first post.

CCM is the best developer for slow to medium speed films I ever used. CCM produces sharp, fine grained negatives with an extraordinary good tonal balance and extremely wide exposure latitude. CCM enhances film speed without any drawbacks. CCM developed negatives are easy to print in the wet darkroom and easy to scan. CCM does not work well with high speed films.

So how can this be? One of the most discussed items about Caffenol in general is fog. Caffenol produces always some base fog and it is regarded as something you should avoid if possible. That's the reason why CCM does not work well with high speed films of 400 ASA boxspeed and faster. The base fog is much too intense, the negs are flat in contrast and the usable speed is more than poor. But with slower speed films it seems to be the reason for the outstanding quality. Fog means that unexposed silver is developed as if it were exposed. But it also means that every silver particle exposed with the smallest amount of light needed for exposure also will be developed. The result is the best shadow detail you can imagine. Most (every?) commercial developers use a fog restraining agent, that will also restrain the low exposed silver developement. By adding some anti-fogging agent to caffenol we would probably end up with an average good developer like so many others. Not so for CCM: without a special pushing procedure you can underexpose up to 4 stops (depending on the used film) and still get very good negs. Don't stress it too much, especially when beginning with Caffenol development. For stress-free easy CCM-development simply double the boxspeed and you will be fine, be it for scanning or wetprinting purpose. Enjoy the results and have fun.

The images displayed in this post are from Hansi, another friend from an analogue photography forum. He used an APX100 35 mm film developed in CCM as outlined here on my blog. Taken with a Nikon F80 with a dedicated 90mm Sigma macro lens. Showing clearly the advantages of a real macro lense. And the first class developement with CCM ;-) Thank you very much, Hansi.

I want to thank everybody involved with this blog. Thank you for all the helpful comments and contributions. Since about 15 years people are using coffee for developing film. I feel that it is still just a beginning....

Best regards - Reinhold

rotation development, sample from Harald

I'm glad to present a report from Harry about rotation development with Caffenol-C-M and scanning from a wetprint made with Agfa MCC baryt paper.

"Inspired by Reinhold´s Blog, I was curious, whether the described recipe would bring me similar results with my accustomed developing procedure. I am using a Jobo ATL-1500 processor for convenience and to get always reproducible results. The ATL-1500 can run only by 24 degree Celsius for B&W mode, and it is a rotating processor. Usually, I begin processing with 5 minutes predunk, so certainly I had to adjust the given developing time of 15 minutes to something less. So I started the first example by using the Agfa APX-100, ISO setting 100 and a developing time of 12,5 minutes.

The results where good, but the density was a little bit high. So I reduced the time to 11,5 minutes for the next film and found it to be perfect. The negatives looked very good and I could not see any drawbacks in terms of quality, compared to my standard developers. The next example I did with a middle format film Agfa APX-100, same processing as before, but I mixed the soup only for 250 ml and I was not very accurate in scaling ... The results, again, where very good. Now I wanted to test the negatives against a print on the very nice Adox MCC baryt paper. What should I tell ? Results where great as you expect it from a good negative.

So my conclusion: This recipe can be used as a serious developer with reproducible results without any drawbacks.

Thanks to Reinhold for this useful blog :-)"

Thank you very much, Harry.