These are Self-Portrait samples my co-teacher-tutor and I produced using the same media but with a varying application of the Subtractive / Additive  technique. 

 We both treated the white paper with charcoal buffed to achieve a mid-tone value after having taped the white drawing paper to the board.  Mine is more extreme in its range of values. Whereas his is more in the mid value range. Both are totally acceptable results.

This Self Portrait Assignment starts by taping your paper to a board. You must tape around the entire each / perimeter of the paper.

 Then lightly covering the paper with Compressed Charcoal.  Then using a rough paper towel, rub in the charcoal until it is an even gray tone or hue.

Now using the mirror, study your face.  Using the eraser …. start to draw your features.  Keep in mind to draw yourself exactly the way you look in the mirror. Do not draw from a photograph or phone! Do not draw a cartoon version or avatar of you...but go for a naturalistic detailed look.

Using the Charcoal......add the grays and darks.  Blend and smooth all the tones using a rolled piece of paper towel...or your Stub.  Stubs were listed in your Course Syllabus as a routine supply item.

You will find this charcoal is easy to erase whenever you want to redo parts of your drawing.

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NOTE:

This is the Subtractive / Additive Technique in Drawing.  The Italian Renaissance era artists referred to it as Chairoscuro: Going from light to darks. The treatment of light & shade in a drawing and painting. An effect of contrasted light and shadow falling unevenly or from a particilaar direction on something.

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 Art often teaches us that there are more than one correct solution to a challenge.

 Students learn that the buffing process is a slow yet vital aspect of this project.

 Process, media and techniques matter.

This is the value range we want.  Now the student-artist can study themselves and begin drawing with charcoal and the eraser.