Please would you quote what book you've just read this in !


Quote Originally Posted by Photo Engineer
If pH goes up, contrast will go up and interlayer interimage as a function of diffusion effects (depth or position within the coating) will generally decrease depending on the magnitude of the error. But this depends on whether the pH error is in the quantity of sodium carbonate or of sodium hydroxide. Both increase pH, but only carbonate increases buffer capacity (see my other posts on the thread regarding semi-stand development for more information). The error may be small.

Decreased pH will decrease contrast and increase interimage as a funtion of 'depth' into the coating. Both of these will affect color reproduction and the red speed relative to green and blue.

Iodide changes are more subtle. Iodide is released along with bromide from the developing grain and acts as a powerful restrainer. If iodide ion is absent from the developer, then edge effects tend to be enhanced, and you can get a 'halo' effect around dark objects. This is hard to see unless you look at magnified images. Too much iodide can lower speed and sharpness.

Bromide variations are similar to iodide variations in effect, but less powerful. Both can lead to 'drag' if the wrong levels and wrong agitation are used. Low levels of either tend to exaggerate agitation problems and increase drag effects. Depending on the film type, you could get iodide drag. High speed films are generally higher in silver and iodide content so it may vary from film to film.

The developer and film are adjusted against each other to maintain the correct results in the presence of an exact ratio of these two halides.

At the least you might just see fair or even good color, but the neutrals might be off, or the reverse might be true, with good neutrals and offish colors. More subtly, you might see less sharpness or higher grain.

This all begs the issue of what happens if you use a blix instead of a bleach fix. Film blixes are hard to formulate, and retained silver is a common problem with them leading to higher contrast and desaturated colors. Sometimes, cyan leuco dye can form if there are errors in the blix formula, especially pH.