I don't have a chart for using the blended powder, but it starts off with SPF35 on its own.
For example, 8oz. (weighed) of lotion + .8oz of titanium micronized dioxide (weighed) = SPF20+
The Micronized TD is 10% of the original amount of lotion used (not the finished weight).
If you used 8oz of lotion + .8oz of Micronized ZO, the SPF would be 11-12.
If it's still too confusing, ask!
Sunscreens & SPF
|<4 %||8 %||12 %||20 %|
|2 %||4 %||6 %||10 %|
|5 %||10 %||15 %||25 %|
|3 %||7.5 %||12 %||20 %|
This chart is to provided by my supplier. I can not do any testing internally. Just to be used as a guideline.