Hi johnyg07,
Thanks for contacting us with your question.
You can change bullish candles' color with
upColor option.
If you want to color candles with at least 4% increase in value, then for example you can iterate over all points and compare each point with previous one.
Demo: https://jsfiddle.net/BlackLabel/bfp4350u/
You have to correct these calculations but this demo should give you general idea how to do something like that. Another option that you have, is to parse your data before passing it to the chart, and set color for each point, following format specified here:
https://api.highcharts.com/highstock/se ... stick.data
Let me know if you have any further questions!
Regards!