Number of Dyes used in color negative and in a product family?

Ted Baker · Jul 30, 2019

How many color dyes are used in a single colour negative film?

Say porta 160 is it just four? a dye each for the red green and blue layers plus one dye for the colour coupler? or is there two colour coupler dyes? or two dyes for different densities for the red sensitive layer? etc etc.

In the kodak suite of colour negative films how many different dyes are used across the product lines? e.g. do modern films share the same dyes, all or some etc?

Prefer facts not guesses

Neil Grant · Jul 30, 2019

..why do you need to know this? Is the colored coupler already colored at it's time of dispersion into the film, or does it only gain color after chromogenic development when it reacts with the oxidised part of the color developer? Just like the other three couplers do. The dyes produced by chromogenic development are spectrally quite imperfect so it probably wouldn't be a good idea to have multiple dyes where one would do. How many dyes were in the Technicolor process? Not a chromogenic process - but should give you a clue.

Ted Baker · Jul 30, 2019

Neil Grant said:
..why do you need to know this?

When conducting research, facts are very useful Facts are useful when making tests and building calibrated equipment and software based on assertions...

To be clear I am only interested in end product after development. i.e. How many dyes exist in a developed negative.

Neil Grant said:
How many dyes were in the Technicolor process?

In the negative I think the answer is none? Anything beyond colour negative is of no interest.

MattKing · Jul 30, 2019

Ted Baker said:
To be clear I am only interested in end product after development. i.e. How many dyes exist in a developed negative.

If you still can, you may wish to add this to the original post.

Photo Engineer · Jul 30, 2019

There are 3 main dyes, C/M/Y, but they differ having come from up to 9 or even more different couplers and can form slightly different dyes to trim the final image to give the best color reproduction.

These couplers would be the primary C/M/Y couplers, the 2 or more DIR couplers, the 2 or more masking couplers and a few others for good measure. The mask is present when coated. It is not formed during the process.

PE

cmacd123 · Jul 30, 2019

not to mention some films have a "4th colour layer" which one would assume may have a slightly different dye set produced.

some folks develop their film with "the wrong" developer, which MAY produce a slightly different Dye than the factory intended. ANd every Version of a given film may have revisions. (ever notice a digit like 6 beside the film name on the cartridge.?)

AgX · Jul 31, 2019

Photo Engineer said:
The mask is present when coated. It is not formed during the process.

To the contrary:

The mask is just formed by processing, imagewise.
Before processing there is just a uniform hue to the film, due to the coloured couplers. But this is no mask yet.

Ted Baker · Jul 31, 2019

Photo Engineer said:
There are 3 main dyes, C/M/Y, but they differ having come from up to 9 or even more different couplers and can form slightly different dyes to trim the final image to give the best color reproduction.

These couplers would be the primary C/M/Y couplers, the 2 or more DIR couplers, the 2 or more masking couplers and a few others for good measure. The mask is present when coated. It is not formed during the process.

PE

Fascinating PE, a follow on question... Asking my original question in a slightly different way, if I had a developed colour negative of step wedge (i.e. and image representative of all possible densities). From a chemical perspective would I end up with something like the following?

1. A compound for the red layer (cyan dye) actually possible three possible compounds
2. A compound for the green layer (magenta dye) actually possible three possible compounds
3. A compound for the blue layer (yellow dye) actually possible three possible compounds
4. Two compounds of what ever is remaining in the mask, that has not been removed because there is no density in the corresponding layers that the mask is intended to correct for.

Ted Baker · Jul 31, 2019

AgX said:
Ted, this shows basic ignorance on the way any modern colour film is madeup.

Why then do you insist on precise numbers of couplers employed and not guesses?

Well If one does not wish to remain ignorant then a possible remedy is to ask questions and have them answered with facts, otherwise someone is likely to be ill informed...

AgX · Jul 31, 2019

As PE already indicated, next to the sensitizing and imageforming dyes, which number already may differ due to sub-layers, there are also various accessory dyes. Thus you would get a different number for most films.

Photo Engineer · Jul 31, 2019

AgX said:
To the contrary:

The mask is just formed by processing, imagewise.
Before processing there is just a uniform hue to the film, due to the coloured couplers. But this is no mask yet.

Yes, a typo. That should read "masking dyes".

Thanks for the catch.

PE

Photo Engineer · Jul 31, 2019

Ted Baker said:
Fascinating PE, a follow on question... Asking my original question in a slightly different way, if I had a developed colour negative of step wedge (i.e. and image representative of all possible densities). From a chemical perspective would I end up with something like the following?

1. A compound for the red layer (cyan dye) actually possible three possible compounds
2. A compound for the green layer (magenta dye) actually possible three possible compounds
3. A compound for the blue layer (yellow dye) actually possible three possible compounds
4. Two compounds of what ever is remaining in the mask, that has not been removed because there is no density in the corresponding layers that the mask is intended to correct for.

This is essentially correct.

There are also the coupler solvents, inhibitors, stabilizers and interlayer scavengers which prevent crosstalk between layers.

PE

Number of Dyes used in color negative and in a product family?

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