I thought a bit of historical research would be helpful. The current Raphael exhibition at the Ashmolean Museum, Oxford comes in handy. These images are taken from 'Raphael, the drawings', Ashmolean Museum, Oxford, 2017.
His work is incredible: in this image above (p107), he creates depth in the folds of fabric around the figure: fine cross hatching creates shadow, building up the darkest tones, while the untouched paper provides the highlights. Some of the hatching follows the plane of the folded fabric.
These (left p109, right p104) have stronger outlines and simplified hatching following the forms more obviously than the previous image.
This image (p151), seems to bridge the two above, with both strong outlines and more complex hatching: some directly follows the planes of the figures and limbs, then some cross-hatching adds greater depth of tone and complexity to the planes depicting muscle, bone and skin.
In this delicate image (p183) Raphael has used white chalk to emphasise highlights, allowing the paper to provide a mid-tone. Again both outline and hatching as well as some delicate highlights where the hatching has blended into areas of light.