My big problem is everyone answers this question in multiple threads with a simple link to elsewhere on glowforge.com or worst and most common case with a link to an unrelated site. I feel like it’s time for some of this knowledge to be moved local to these forums.
and now to do that which I accuse all others of.
https://www.coherent.com/Applications/index.cfm?fuseaction=forms.AppLevel2&AppLevel2ID=110
and then to summarize locally.
Basically the Mac book marking is using a property of anodized(I think it’s a color/texturing process) aluminum to remove coloring from the anodized layer and turn it white. By comparison I think you could use Cermark/Thermark to make black marks instead of white.
Anodized Aluminum(https://en.wikipedia.org/wiki/Anodizing#Anodized_aluminium)
to quote:
Aluminium alloys are anodized to increase corrosion resistance and to allow dyeing (coloring), improved lubrication, or improved adhesion. However, anodizing does not increase the strength of the aluminium object. The anodic layer is non-conductive.[3]
So there I’ve done it all wrong. linked external sites and added more speculation where I think most people want a stamp of authenticity from Glowforge/Dan.