Material-Test settings for black engraving on aluminum

[Pappatoad (Todd)]

Hello everyone, I am newer to this forum and have been working with Lightburn and my OMTech 60 watt MOPA Fiber laser. I am trying to configure a materials test for aluminum to get the black oxidized look on the engravings. So far I am getting only brown to dark brown. I am looking for some suggestions on what settings to use to get a materials-test going so I can see the results. I have tried modifying other settings based on what I found on the web for other brands of MOPA Lasers that are also 60 watt, but I am not getting any results for black images or letters on Aluminum. If anyone has an OMTech 60watt MOPA Fiber laser and can suggest some settings I would be most appreciative.
The last test where I got the browns was set like this:
Speed: 500 mms
PWR: 85%
Interval: .0250
Passes: 1

(Variables for test)
Frequency: 10-100
Q-Pulse: 200-400

Todd

[jkwilborn (Jack Wilborn)]

As far as I know there is no ability to create black on aluminum without a coating of some type, such as Brilliance – who have a special chemistry to lase black on aluminum.

[Pappatoad (Todd)]

Thanks for the information, I was getting puzzled by the numerous videos on youtube showing lasers engraving into aluminum that showed up as black fill or lines. They show typical aluminum pieces being engraved with black lettering or images.
I will look into Brilliance for the black on aluminum effect.