With the new update, in vivo SPF experiments will use standards based off three categories: low, middle, and high. If the estimated SPF is under 25, then all subjects use P2 or P3 as a standard. When the estimated SPF is 25 or more, but less than 50, ISO requires at least five people use the mid-range standards: P5 or P6 (N/A) with the rest using P2/P3. Finally, at SPF 50 and above ISO requires at least five people use the high range standard P8, with the rest using P2/P3. Spreading times are now only 35s +/-15s with the technique requiring small individual circles followed by alternating vertical and horizontal lines.