How Mario Zucca manages to say so much with so few lines is a testament to his talent. His illustration style is clear and easy to read, and his color works well. I would guess that the color is probably done digitally. On his website he has a series of portraits from his high school yearbook in scratchboard. They are quirky and fun to look at.
Several things about this image are worth mentioning. I love the textures on the surface of the table and the floor. They are made with rows of line segments. This gives more character to the surface than if the lines were totally straight and continuous. The lamp is another example of varied line treatments as it turns from dark to light.
Nicolas Delort does some impressive work. If you click the image it takes you to a visual tutorial of the process. It would be nice if there were some text to go with it. For this piece it looks like he started with a digital sketch that he refined and then traced onto white scratchboard. It looks like he first inked the major outline of the wave and then inked the rest of the surface with some kind of brush-tip marker. It also looks like he is doing quite a bit of line work with the pen in certain areas. Other parts are scratched. Some of his work is very reminiscent of Franklin Booth, which would make sense. Booth imitated etching patterns with pen and ink.
This image links to several other images, and the influence of Franklin Booth is very apparent – especially the clouds. I love the massive appearance of the spaceship. It’s retro and sort of scary and friendly at the same time.