Task to Remote Surroundings, recommended max ratio 10:1
The first graph below shows the luminance ratios for the Task to Remote Surroundings view context (max of such ratios, where appropriate, as, Book to Window Sill, or to wall between windows, Shade Shelf, or Floor) for each station and time, as measured on March 18th, 2005. The very high contrasts for Station 3 are those between the luminance of the book and the shade shelf. When looking forward, both could be in one's field of view, but, when looking down at the paper, the shade shelf would not be visible. The remaining contrasts are all within range. Not included here is the contrast between book and window, which would also be an unlikely contrast when looking down at the work, and which would have totally skewed the graph upwards to from about 10:1 to maybe as high as 60:1.
This next graph shows, as above, the luminance ratios for the Task to Remote Surroundings view context but over all of my measurement days, and includes some ratios which I did not measure on the 18th, namely, Book to Wall on the Far Left and Book to Partition. Here, again, the same high contrasts exist for station 3's Book to Shade shelf. In addition, there is a large spike for station 2 B, which is a contrast between the Book and the Partition to the left, which had an unusually low measurement: I probably measured this in a dark spot, and I think it is probably a fluke. Other than these spikes, the rest of the ratios are well within the 10:1 recommended maximum.
