Making Curves for ETTR Footage

So, we’ve exposed to the right in order to reduce noise in the image; we’ve chosen the logarithmic color space of the hero camera as our working color space; and our timeline luminance matches the output color space. How are we to normalize the footage to prepare it for grading? There are a number of ways to normalize ETTR footage for grading, one of which is to simply add a bowl-shaped custom curve on the color page. Another way is to decrease the ISO in the RAW panel of the color page and add an S-curve. In this test, we wanted to determine what difference if any either of these two methods had on contrast, saturation, noise and overall image quality. In Figure 1, we left the ISO at 800 and added a bowl-shaped curve to prepare the footage for grading, while in figure 2, we decreased the ISO to 250 and applied an S-curve. Figures 3 and 4 show the image enlarged 999% to determine whether there is any difference in noise in the shadows, while figure 5, the chromaticity scope, give us an idea of the saturation of the image using both techniques. Figures 6 and 8 are of the waveform monitor at ISO 250 and ISO 800.

There are differences, but it probably just comes down to your curve-drawing ability more than anything else! We’re still leaning toward Gerald Undone’s method, though we’re guessing the vast majority of colorists are just decreasing ISO or using the gain wheel (if working in SDR) to reduce brightness.