Sanded Lodge seasons brown?

[DaltonC]

In my introduction I mentioned having a new 12" Lodge skillet. My first googling lead me to believe I would need to sand down the rough texture, and so I went. E-bath, RO sander 60 grit, 120 grit, 220 grit, clean, and re-season.

I now know it wasn't necessary, and I wouldn't dream of doing it to vintage, but it's done, and I noticed something I am curious about.

I have re-seasoned it 3 times now. Once with lard, one with vegetable oil, and once with grape seed oil. All three times lead to the same result. The outside bumpy surface immediately turns black again after 1 trip through the oven. The inside surface, even after 6 trips through only turns a (beautiful, admittedly) bronze color.

What is happening here? I know eventually the inside will blacken as well, but I'm curious as to why the textured part blackens so much more readily.

 

[W. Hilditch]

Where you sanded the surface it is a lot more silvery and lighter than the original casting, which probably still had some of the black factory seasoning on it. As your added seasoning hasn’t yet carbonized your are looking through it to a dark surface on the outside and a lighter surface where you sanded. The seasoning you added is the same color inside and out.

Hilditch

 

[DaltonC]

Where you sanded the surface it is a lot more silvery and lighter than the original casting, which probably still had some of the black factory seasoning on it. As your added seasoning hasn’t yet carbonized your are looking through it to a dark surface on the outside and a lighter surface where you sanded. The seasoning you added is the same color inside and out.

Hilditch

I've read that explanation, and it mostly makes sense. The bolded part is what throws me. I figured that with the outside starting out dull grey, a brownish color would still be fairly obvious even on that. But the outside is just as black as when new.

 

[W. Hilditch]

In the right light either your eye or your camera will see that bronze glow on the outside. When I think something I have a 51% chance of being right. When I figure something it drops a lot.

Hilditch

 

[DaltonC]

In the right light either your eye or your camera will see that bronze glow on the outside. When I think something I have a 51% chance of being right. When I figure something it drops a lot.

Hilditch

Ahh! One of those things where my use of "daylight" color temperature light bulbs instead of the normal soft white would affect what I'm seeing.