Mixing your own color chemistry

[Photo Engineer]

I have been asked by several people in the last 6 months to comment on their own brand of home brew color chemistry.

Here is the hardest point to make with anyone, and I am sharing it with you.

Do not use the wrong color developing agent for your material!

CD3 = E6 and RA
CD4 = C41
CD6 = Kodachrome yellow only, the M and C are CD3

If you use CD4 for color paper, you will get desaturated colors and about 1/2 to 1/4th the image stability. Your pictures will fade very quickly if CD4 is used for color papers. This is also true for CD4 use in E6. Very bad for color and image stability.

Use of CD3 in place of CD4 for films will give desaturated images with low Dmax unless you compensate in the formula by using a booster to improve dye yeild. No, I will not offer any suggestions! Too chancy.

CD6 remains untested at this point in any modern product except Kodachrome. At the time we ceased testing at EK, it was beating everything hands down on a number of fronts, but just a change in coupler could negate that picture so I cannot suggest that anyone use CD6.

The older developing agents, CD1 and CD2 are much more prone to cause skin problems (dermatitis) and to give much poorer dye stability and hue. Besides which, they tend to form tar and oil as the developer is used.

There is the summary for you if you want to make your own.

PE

 

[hka]

Thanks PE this information is very helpfull.

 

[Mick Fagan]

Yes, quite helpful.

Once I mixed up some paper developer with CD4 to see what would happen, flat colours, as for fading, well not the prints I have had, which is about 8 years. Well just a little bit of fading.

Was there ever a CD5?

Mick.

 

[Photo Engineer]

Yes, there was a CD5. I forget exactly what it was. These are not the numbers that they are known by at Kodak. There is an internal classification system based on structure, and I remember them more by that method so as to keep the structures clear in my mind. (In fact, there are 2 internal systems, but one is defunct but still used by some.)

PE

 

[David Brown]

There is the summary for you if you want to make your own.

Reference or link?

 

[Photo Engineer]

Reference or link?

David;

I will leave the formulas to those who wish to publish them. I don't have any plans at the current time to publish any color formulas.

The links and references abound here on APUG, with examples.

PE

 

[Heinz_Anderle]

A patent search will help, as the respective patents can be accessed and downloaded for free today. The main obstacle is the vast number of color photography patents.

As the commercial value of silver halide technology appears to be decreasing, and further improvements in technology and quality are less likely, and some manufacturers have left the business, will such patents, upheld to impede the competitors, become abandoned before their 20-year span?

 

[Photo Engineer]

Heinz;

The Kodachrome patent has been abandoned. So, I think the answer is not only "yes" but that the formulas will be published at some time.

PE

 

[RPC]

Photographer's Formulary doesn't seem to stock CD-3, and I recall seeing somewhere on their online store, the comment "CD-3 users should use CD-4". Someone should set them straight.

RPC

 

[srs5694]

FWIW, Art Craft has CD-3 but not CD-4. At one time Art Craft had both CD-3 and CD-4 and Photographer's Formulary had neither, so overall availability hasn't changed in a while, but they're both fairly hard to get compared to many other ingredients.

 

[Photo Engineer]

The Photographers Formulary has Hydroxyl Amine Sulfate as well. They also have CD2.

I will try to contact them and correct that statement about using CD4 instead of CD3.

PE

 

[Heinz_Anderle]

Heinz;

The Kodachrome patent has been abandoned. So, I think the answer is not only "yes" but that the formulas will be published at some time.

PE

As Kodachrome 25 and 64 were introduced already in 1974, the (European) patents should have expired about 1995 - US Patents of that time lasted for 17 years after the grant date, and thus could be "extended" somewhat with the duration of the patent examination ;-)

A newer review article by Theys and Sosnovsky, "Chemistry and processes of color photography"; Chem Rev 97 (1997), 83 - 132, quotes many patents. Today, we have the free internet databases.

 

[Photo Engineer]

Heinz;

The Kodachrome patent was abandoned in the early 80s IIRC, while still in force. It was abandoned when Fuji decided to leave the Kodachrome market leaving Kodak with no Kodachrome competitors and with high maintenance fees on the patent costing them money all around the world. So, this was a freebie to everyone.

PE

 

[Terence Spross]

Where to obtain CD6?

If I could obtain CD6, I could resume my Kodachrome experiments.

 

[Photo Engineer]

If I could obtain CD6, I could resume my Kodachrome experiments.

I have no idea, nor any way to help.

PE

 

[nickandre]

Where can one buy CMY color couplers?

Nevermind, I'll call kodak tomorrow.

 

[Photo Engineer]

CMY couplers were listed in the Kodak professional products catalog until about 1990. Now.......

Anyhow, I have some catalog numbers, no doubt out of date and prices which include an arm, a leg, an eye and an ear to start with. Things get grim after this short list......

Try Tennesee Eastman instead!

PE