Modern color films are incorporated meaning the dyes are placed in the emulsion during manufacture. We are talking, C-41 color negative film and E-6 color positive films. These films entail multiple coats of gelatin laced with light sensitive salts of silver and dye in a leuco state (Greek for white). The silver salts in each coat have been adjusted so that they are sensitive mainly to one of the three light primary colors which is red, green, and blue.

The topmost coasts are sensitive to blue, and they contain leuco yellow. The middle coats are sensitive green and contain leuco magenta. The bottom coats are sensitive to red and contain leuco cyan. Yellow, magenta, and cyan are the subtractive primary colors (complementary or opposite of the light primaries).

After exposure in the camera, a high percentage of silver salts have been exposed to light and thus developable. The job of the developer is to identity exposed salts of silver and reduce them to their two component parts which are silver and a halogen (Swedish “salt maker” usually bromine but could be chlorine or iodine).

As the developer works and reduce exposed silver salts, the halogen component is liberated and thus goes into solution into the waters of the developer. As more and more film is developed the developer solution thus gains more and more bromine. In addition to the developing containing agents that reduce exposed silver salts (black & white developing agents, there is a color developing agent. Its job is to unite with leuco dye and convert it to a full-blown dye by supplying a missing ingredient. All three subtractive dye globules are missing the same single ingredient.

The mechanisms is, as the black & white agent works, metallic silver is deposited in each emulsion in proportion to the exposing light. Each emulsion contains the appropriate leuco dye. As silver materializes it oxidizes as the waters of the developer contain dissolved oxygen. Silver oxide is the catalyst that caused the color developer to combine with an adjacent globule of leuco dye. The color developer now supplies a missing dye ingredient and the leuco dye now blossoms into a full-blown dye. All three leuco dyes are missing the same common independent. This is the marvel of these processes.

The C-41 and E-6 processes were chiefly designed to operate in automated processing machines whereby the chemicals of the process have an indefinite life span if correctly replenished. The replenisher formulas are balanced to replace exhausted ingredients and maintain the pH and concentration. The key ingredients of a developer:

1. Water solvent
2. Black & white developing agents
3. Color developer
4. Accelerator to set pH. Mostly developers work in an alkaline environment, the more alkaline the more energetic.
5. Restrainer that retards development preventing the development of unexposed silver salts (usually bromine).
6. Preservative that slows aerial oxidation and reacts with oxidized products to neutralize and limit the staining they induce.

The C-41 and E-6 formulas, being mainly for highspeed machines are sold as replenisher formulas. As such, when the machine is initially started, the replenisher solutions must be tweaked to make a working tank solution. The developer replenisher formula comes too strong and missing the restrainer. This is because the restrainer is bromine, a halogen which is liberated as the films develop. If the replenisher solution contained bromine, tank formula will now under-develop. Thus, using a straight replenisher formula tends to over-develop until the needed bromine is gained due to film volume. Plus, the pH will be wrong.

The E-6 and C-41 processes depend on a specific infusion rate. The top blue emulsions are wet first so development stars in the blue layers followed in time by green and red. The infusion rate is based on temperature and pH as this control the hardness of the emulsion. If the infusion rate is off and or the chemical makeup is wrong, likely the final color balance of the film will be off specification.

About the fixer -- No starter for the fixer, only dilute the concentrate to working tank strenght.

Starter for bleach -- The bleach solution is very pH dependent. The cyan, magenta, and yellow dyes used are organic and organic stuff lives in a world of narrow pH. The bleach starter sets the pH, if wrong the dyes revert to a leuco state. The working bleach tank depends on carryover fluid to set the pH. A fresh mix of machine type formula will not be at the proper pH without the starter.