To make a "rainbow" burst flash, you can just set the color gel to a half magenta and half yellow or half blue and half green. However, sometimes, we get an extreme flash burn from the Colorsplash Flash instead. It's because our distance is too close when we take a shot from the object.
To avoid that “burning” flash, we must keep our distance from our subject and make sure we’re not too close. I’ve tried this quick and simple trick, so I’ll show you the results.
These are some examples from 0.8 until 1.5 meter distance setting:
And this are the results from 3m distance setting:
So you can approximate your distance before you take a picture. If you get into the habit of this distance setting, then you can do the “Don’t think just shoot” rule!