help for flawless rendering

Hello, i'm a uf6 apprentice and I have a question.

I'm testing and studying Kerry Michell tutorials
As you can see, my image is not as perfect as the image obtained http://www.kerrymitchellart.com/tutorials/basket/basket.html

I have made a copy and pasted of the upr of kerry and I have rendered, then I have compared both images and mine imge has defects. because?

you can help me?
I am Spanish and I have used google translator

400 by 400 pixels is not enough to resolve the image. With normal anti-aliasing, rendering at 1080 by 1080 was not quite enough. 2000 by 2000 was enough.

Even with custom anti-aliasing [ 0.1, 4, 9 (3x3) ], 400 by 400 didn't come out well. Often rendering the image larger and reducing it afterwards works better than trying to improve the anti-aliasing.

I suspect that Kerry Mitchell rendered it at 2000 by 2000 and used another program to reduce it to 400 by 400. I did that and it looked just like his illustration. Good free programs for image reduction and other image manipulation include Irfanview and FastStone.

Muchas gracias.

De nada.

(That nearly exhausts what Spanish I remember from high school many decades ago.)

In this case, you can also try to use the "Non-adaptive" anti-aliasing option. The other options use adaptive anti-aliasing, where a pixel is anti-aliased only if it differs from its neighbors. That usually works well, but not with these black-and-white images, because fine filaments are easily missed.
https://www.ultrafractal.com/help/exporting/antialiasing.html