Many photographs do not work. Subsequently, we find out they do not work because there is a difference between what you saw and what your audience sees in the image. Sometimes this comes down to lack of skill in translating an idea, but often it’s more subtle than that: the camera doesn’t see what we see, and we need to be both highly aware of that and how to compensate for it. Yesterday’s photoessay is a good example: it’s no big deal to make a monochrome image, but our eyes only perceive a lack of color under very exceptional circumstances. Yet it’s these differences that make some images stand out, and others not really ‘work’. There are a few important properties of the eye/brain combination to note: firstly, we have an incredibly wide dynamic range, but it isn’t linear. Highlights seldom clip to white or oversaturate, though blacks go black fairly quickly. Also, our vision switches to luminance-sensitive rods at lower brightness levels, meaning that the darker it gets, the more desaturated and flat things appear. A camera mostly maintains linear tonal response across the entire tonal range, and thus the final output will look different to both what we see and our idea of how a scene of that given brightness should look…….