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CD-4 and CD-3 what's the difference?

E Kawaguchi , Apr 01, 2006; 02:02 p.m.

Hello all.
I recently began C41 process for color negatives of 120 and 4X5 sizes, making color developer for myself using CD-4.
The result was almost successful. Then I tried pseudo E-6 process for KODAK EPR and FUJI RDP III;

1. first develope - exact E-6 formularated developer refered to in my dark room book (extremely DENSE! formulate compared to B&W developer) and time is the exact minutes instructed.
2. reverse - 200W electric-bulb light for about 3 minutes
3. color develope - the same one as I use in C-41 process (containing CD-4) for 1.2-1.5 times longer minutes than in normal C-41 process
4 BL and FIX - the same as in C-41

This results in farely satisfactory positive images for first trial; colors seem almost normal and normal exposure is gained. CD-4 works fine much more than expected. I attach an image (EPR) from this pseudo E-6 process.
However I can't get rid of thought that I may be blined from something.
I am wondering if stepping up to normal E-6 color developer (with CD- 3 containd and other complexed chemicals ) promises the more satisfactory results I get from professinoal labs. What the difference between CD-4 and CD-3 and how much they differs?

Any advise is appreciated. (also I apogize for my poor English skills)


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Rowland Mowrey , Apr 01, 2006; 08:46 p.m.

CD3 and CD4 produce different dyes with different hues and saturation. The E6 color developer is very much different than the C41 color developer even taking into consideration the differences between CD3 and CD4.

Most of the published formulas that I have seen for E6 and C41 are incorrect. You are lucky you got a usable image at all.

Ron Mowrey

Dan Schwartz , Apr 01, 2006; 09:00 p.m.

I would recommend buying the Kodak or Fuji-Hunt color developer, as that is where much of the "secret sauce" seems to be hidden. The amount of money you pay for it is small compared to the cost of the film.

Also, I would suggest using a chemical reversal bath, as it is more consistent than using light reversal, especially for roll film on a reel. Using chemical reversal also helps prevent reticulation (which is physical damage to the emulsion because of wide temperature changes) as you go from 100F in the first wash down to 70F room temperature for the re-exposure, then back up again to 100F for the color developer bath.

As I just mentioned in this thread http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00FsRE reversal bath and pre-bleach is so inexpensive that it does not pay to replenish; in other words, just use it once and flush.

Also, even though Ron is a bit more pessimistic than me, I am glad to find that there are still hobbyists out there willing to experiment with color film developing! :)

Rowland Mowrey , Apr 02, 2006; 02:21 p.m.

Just for your information, the C41 developer produces dyes intended for viewing by print materials, whereas the E6 process produces dyes intended for viewing by the human eye. Therefore the peak absorption and half band widths of the dyes produced by the two developing agents differ.

In addition, the E6 first and color developers are what might be termed the color equivalents of High Acutance or High Solvent developers to eke out the highest sharpness at the lowest grain, while the C41 developer is a relatively low acutance developer which relies on the contents of the film itself (DIR couplers for example) to improve sharpness and grain.

Ron Mowrey

E Kawaguchi , Apr 02, 2006; 05:46 p.m.

Ron, thank you for responses. So it can be said CD-4 produces dyes ideal for print paper to be exposed whereas CD-3 dyes that is to be seen directly by human eyes. Is that correct?

Highest acutance and finest grain-that seems difficult to realize in B&W formulas. High acutance devloper like Beutler formula loses some grain. My 1st devloper formula has 30g hydoroquinon and 2g phenidone that means about ten times density than usual B&W developer formula, as well as it is instructed to process 30 degree at 15 minutes. Those formula, temp, time might be said crazy if it were for B&W negatives. Things are much different. Oh sure, I noticed my C-41 images have less sharpness.

DAN, I once tried in vain to find out some dealer in my country which sells genuine Kodak or Fuji developer. Furtheremore, there some amateuer kit used to be sold for E6 process like TETENAL but at this time all have been discontinued. Such kits only remains for C41 and color paper but rather expensive. Some incidents since 11 years ago have made our society sensitive for chemicals and major shops (like Yodobashi camera or Big camera, do you know?) are unwilling to deal with those product. That tendency seems to be enhanced by less demand for films as digital cameras dominates the market. Oh I wish I could taste 'secret sauce'.

The first reason for beginning C41 developing by myself is lab's developing price is high for sheet films (about $3 per sheet). I could get many color nagetive films in 4X5 for very cheap, then that problem came. Since I have confidence in me at C41 I will usually develope color negatives at my house. Besides I also be aware of AMAZING color positives I had in this experience. Though this experiment just falls within 'psedo E6' but now I feel I can proceed to regular E6 process. I think it is worth to be done and very significant to me.

Terence Spross , Apr 03, 2006; 09:40 a.m.

Ron - Most of the published formulas that I have seen for E6 and C41 are incorrect Is there a site where the results of various C41 and/or E6 formula are compared? Are the real C41 / E6 formulas published anywhere? I didn't find anything at the University of Rochester library. I plan on trying the Rochester Institute of Technology Library next where I found a detailed Kodak spec on E4 years ago. I want to mix up a batch of C41 soon but don't want to waste my time on compromised formula. More complicated or longer lists of chemicals don't scare me, although cost is a factor. I want to develop C41 in an accurate single developer first and then experiment with a two bath developer for the purpose of controling contrast as in a two bath B&W developer. I also have a large amount of Kodak 5247 that was exposed long ago that is very important to me and I want to cross-process for the purpose of scanning and losing the least amount possible as I know reversal processing for projection could never yeild the best results on expired film. Dan - What is wrong with doing the reexposure on the reel? I have on old Ansco tank that is transparent on the top side and allows me to flood light reverse exposure with the tank cover off but while the film is still submerged in the stop bath. I last did this with a 75 degree B&W reversal process with good results. E Kawaguchi - Are you reverse exposing with the film still in the tank?

Rowland Mowrey , Apr 03, 2006; 11:50 a.m.

Kawaguchi san;

Joto desu! Yes, you have it right about CD4 and CD3. Also, dye stability will not be correct if you cross develop films for one developer with another.

In addition, the E6 developers are what might be termed high acutance due to their use with color materials with high iodide. The HA also works well due to the levels of silver and the way a reversal image is formed. The level of Hydroquinone you mention is wrong. In fact, E6 does NOT use hydroquinone in the first developer - surprise surprise.... It also uses several other ingredients which are either missing or changed in most formulas.


The closest formulas I ever saw were published in the old Darkroom Techniques magazine about 10 years ago. There were some comparisons then with several different 3rd party kits as well IIRC, but the one I recall was for C41.

Basically, the published E6 formulas are pretty far out, but the C41 formulas are rather a bit closer. The C41 chemistry is disclosed in several EK patents. It has few ingredients that are unusual or exotic, but the E6 chemistry has a lot of exotic stuff in it in both developers, the pre-bleach and etc. Some of the E6 chemistry is either hard to get or very expensive!

I gather you are in Rochester, so you can probably call me on the phone.

Ron Mowrey

E Kawaguchi , Apr 03, 2006; 01:52 p.m.

>Terence Spross When I do reverse exposure, I get the film out of the reel, then after exposing, I set it back to the reel. It's somawhat a mess and take time up to ten minute's, but at this time I want to make it for sure. However, someone in my country do this as just the film putting inside the reel in water, lighting by 500W bulb, leaving it for ten minutes, then gets the same result.

According to my darkroom book Kodak never ever disclose the genuine C41 formula, but for business labs dealing major quantity, KODAK leaves a formula called 'C-42'. The formula is mostly consisted of our usual B&W chemicals, except hydoroqusylamin? (NH2OH)2 H2SO4 and KODAK anti carcium NO4.

Rowland Mowrey , Apr 03, 2006; 01:57 p.m.

You are referring to the sulfuric acid salt of hydroxyl amine. There are several chemical companies in Japan (assuming that is where you are) and many in the US that sell it.

The other chemical is similar to quadrofos which is a sequestering agent.

Ron Mowrey

E Kawaguchi , Apr 03, 2006; 02:06 p.m.

>Rowland Mowrey

E6 does not use hydroquinone? Hmm what a mystery. Ah I have to say that my book means hydroquinone-mono-sulfate (maybe not the exact term)but someone says it's equivalent of usual hydroquinone. I observe this seems to contribute to form hard tone images on films like when we enlarging on paper.

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