Iodine Test Paper question

[BearInTheBackyard]

So I'm newer to all grain and picked up some of these iodine test papers.

Per the instructions:
"Color comparison will indicate approx strength of solution in ppm avaialable iodine".

If i perform the test as indicated (dip in solution for 60 seconds, and compare to color chart) and the color chart is as follows- 0ppm will be white, 50ppm will be dark purple, what color will indicate full conversion?

In other words:
When i am mashing, to make sure im converted, do I want purple or white?

 

[Bubba]

I would say white although I never used the paper I just take a drop or two out of the mash add a drop of iodine and when it turns clear ( not dark or purple ) I know i have conversion.

 

[BearInTheBackyard]

Thanks for the reply Bubba. I'm honestly not sure if they are even working. I've been going on the assumption that white=conversion in my last 2 batches, but this batch I decided to test it by testing at 1 minute into my mash - still it's white. It's also white at the end of the mash (even extended the mash to 75 min to make sure).