- Joined
- Aug 6, 2016
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When people talk about developers and film speed, what are they actually talking about and what are we likely to see in a negative.
I think David has explained it pretty well. The box speed is determined by the manufacturer under very specific laboratory conditions. Your personal EI is determined based on sensitometric testing or empirically and is tailored to your personal equipment and workflow. Therefore, film speed is a moving target.
Very simplistically a fine grain developer may work by solvent action and dissolve away developed specks; this may reduce the overall visible grain, but it will also reduce the amount of silver in the image, giving a less dense negative that needs more exposure to compensate. Hence a loss of "film speed".
I understand that bit, but the bit I was not getting was when people refer to developers loosing or increasing film speed or have I misread it
There might be different ideas in peoples' heads when they speak of speed increase. One person might think of needing to get any kind of image at all, despite difficult circumstances, but another might be looking for "...better shadow detail."
In my mind, the first one is associated with 35mm and the second with LF. Others may have different views, of course.