Some alt processes require one to take in the present conditions (temp, Rh, phase of the moon, etc) to achieve a good print...in my case carbon printing and platinum printing. In such situations, instructions are more like suggestions.
Everything in photography. Photography is an art, a craft and a science all rolled into one and you don't ever know how much of each individual one you need at any given time. There are some things that won't show up on a chart and so you need to draw on your experiences. In my humbug opinion.
Some alt processes require one to take in the present conditions (temp, Rh, phase of the moon, etc) to achieve a good print...in my case carbon printing and platinum printing. In such situations, instructions are more like suggestions.