I think that if you want to be able to
make a pencil drawing using a photograph as reference, you will need
to use a value scale.
A value scale is a scale filled with shades of gray or unfilled to show the value or shade of each pencil in a range of values from black to white, being the paper the white
It is used to find the values of a
particular area of a black and white image, drawing or photograph,
by overlaying it and finding areas of similar value through the
holes.
How to make a graphite pencil value scale
To have an idea of which pencil to use
for a given area of a black and white picture, one thing you can use
is a value scale. What i call a value scale is a template printed on
card. This template has separate locations to be filled with graphite
from the different values you have from 9H all the way to 9B. Then
when you have all squares filled with each different pencil you will
have a variation of shades of gray or values from black
(9B) to almost white (9H), and white is represented by the paper
itself. If you make a hole on each value square, now you can compare
the values on the original black and white picture with the values on
your scale, and when the values match you will know which pencil to
use.
You should try to apply the same
pressure on the pencil when filling the value spaces of each pencil
so the result is the most consistent possible. You can cross-hatching
it first drawing horizontal lines and then drawing vertical lines
over the horizontal ones. Try to fill each space the same way.
You can also use a computer generated
scale of pure values for you to compare the reference image,
any area no your drawing or to
calibrate the values of your pencils.
Always remember that different pencil
manufacturers always have different value range for their pencils, so
a 4B from one manufacturer probably is different from the 4B pencil of
another manufacturer.
I have included a file with empty
template value scales I use, i made them in Inkscape, an open source
vector drawing application.
click here for the Value Template
Enjoy drawing.
click here for the Value Template
Enjoy drawing.