I always encourage students to create realistic drawings from direct observation of a three-dimensional subject. However, that is not always possible. In these cases, there are four tools which can help you obtain a good likeness. But be careful! Only use these tools when necessary.
If you use them too much, your eyes will get lazy, and your art will suffer. The sensitivity of your drawing is often lost when you rely purely on crutches like these drawing devices.
Having said all that, there are four tools (besides tracing paper) which can help you make a realistic drawing.
The grid-the oldest and simplest method
The grid method is both Simple and effective to enhance realistic drawing skills. Like Leonardo da Vinci did, I sometimes use g rids to transfer my small sketches to a larger canvas. By large, I mean anything bigger than 30 inches (76 cm) in any direction. The size depends on your personal drawing ability and comfort level when working large. You can also
draw and compose with a very simple grid like this.
I suggest making an extra copy of your source photo so you can draw directly on it. Or you can draw a grid on piece of tracing paper and tape that over the photo. Next you draw an enlarged grid with the same aspect ratio and number of squares on a piece of tracing paper.
For example, if you want your final drawing to be 4 times the size of your reference photo, then quadruple the size of the squares (e.g.from ½ to 2 inches on a side). Then copy the outlines and contours of the major shapes from each square in the reference photo into the corresponding square of the tracing paper.
Take special care to capture the points where the outlines meet the sides of the squares. Soon you'll have an enlarged outline of your subject. Now you can transfer to outline to the canvas without the grid.
Another great tool for nailing down a fairly finished realistic drawing is a projector. The opaque projector comes in a wide variety of styles and prices, but all of them will project a photograph or a realistic drawing of some sort onto a vertical canvas or a screen. You can also project the image onto a piece of tracing paper and then transfer it to any other surface later.
I have found that projected images almost always require correction because the perspective is slightly off. Some distortion is inevitable no matter how sophisticated the projector is.
When you use it, make sure that the lens of the projector is exactly parallel to the target surface to minimize the distortion. Another problem is that the projected image is usually fuzzy and dim, so even when I use a projector, I still have to use the original reference to check the drawing for accuracy.
Keep in mind that you often get what you pay for with projectors. I once bought a cheap one for under 100 dollars, but eventually I had to upgrade to a better one because the image it projected was so faint and distorted.
If you are drawing a complicated subject such as an elaborate architectural facade or a market with lots of figures and stands, then a projector will definitely be a life saver.
This interesting looking instrument can help you accurately enlarge an image. It is not expensive, and depending on the model, it can be set to enlarge images anywhere from two to ten times the size. Like opaque projectors and proportional dividers (discussed below),
pantographs can be found in art supply stores.
To use it, clamp the pantograph to your drawing board, and tape your photo to the board underneath the scriber. Then tape your tracing paper under the pantograph's pencil. When you move the scriber over the photo, your pencil moves correspondingly. You use it to produce an enlarged image of the photo's major outlines.
To maintain better control, you can use both hands to guide the scriber. The tracing you end up with is not complete, but it is often sufficiently accurate to get you started. By referring to your original reference photo, you can fill in the details.
Using a pantograph will take some practice as it is awkward to use at first. Once you are proficient, however, you will be able to use it to create accurate enlargements.
I find that both the pantograph and the grid method produce accurate outline drawings of your subject, but the tracing is rarely perfect. This problem is particularly noticeable when you draw figures or portraits. You can use a ruler and some arithmetic to make corrections, but you'll find it easier to use a proportional divider.
A proportional divider looks like a pair of scissors but with points at all four ends and an adjustable joint. By adjusting the joint you can set the tool to any transfer ratio from 1:1 to 1:10.
For example, when I use the points on the narrow end to measure the width of a mouth, the wide end of the dividers will automatically open to a distance exactly proportional to the width of that mouth. If the width of the mouth in the photo is ¼ inch and the dividers are set at 4-to-1, you can then use them to check whether you enlarged the mouth to 1 inch wide.
Recently, I bought a proportional divider for checking the minute proportions in my portraiture drawings and paintings. It was well worth the money. It saves me time and also the eye strain of measuring tiny proportions. I do free hand measuring a lot of the time, but with portrait commissions I rely on the proportional divider for precision, since there is little room for mistakes.