Absolutely agree that this is an incredibly hard skill in any medium, digital or otherwise.
It's also possible that Van Eyck may have perceived the world the same way we do, and the inclusion of small details such as the beads came only due to his artistic choice of tools. Conversely if you were trained to the same tool for sketching you would be forced to include the beads by way of process -- even if you had not noticed them before.
It's also possible that Van Eyck may have perceived the world the same way we do, and the inclusion of small details such as the beads came only due to his artistic choice of tools. Conversely if you were trained to the same tool for sketching you would be forced to include the beads by way of process -- even if you had not noticed them before.