Graphite paper is an easy way to transfer a sketch. It requires no equipment and is ideal for transferring to boards and panels. It works like the old-fashioned carbon paper. Start with a piece of tracing paper (or other thin paper) and use a graphite stick or soft (4B) pencil to cover one side:
Next tape it to the back of your sketch with the graphite side out, facing away from the sketch:
Tape this to the final board or paper, sketch side up, graphite side down. Now go over the lines of your sketch with a steady, firm (not too firm - don't engrave it) pressure:
The lines are transferred to your final board:
1) If you don't want to alter your sketch by re-tracing the lines, make a photocopy and trace that.
2) If you are transferring a large sketch, you don't need to cover every inch of the back with graphite. Just cover where the lines are.
The basic idea is to shine light through your paper and trace the art onto a top sheet. This method is usually the quickest and most direct. The drawback is that it only works with certain papers - those thin enough to let some light pass through. I use a lightbox for transferring sketches to pen and ink paper and thin watercolor paper. I also use it for transferring messy sketches (those with smudges, erasure ghosts, cat prints and Fritos stains) to clean drawing paper.
If I know I'll be using the lightbox I do my sketches on tracing paper. If the final piece needs to be bigger or smaller use a photocopier. Make any reductions or enlargements as needed and use the copy on the lightbox. The benefits of making a photocopy are: 1) copy paper is thin making it easier to trace and 2) when making a copy you can adjust the image quality and darken up your pencil lines - again, easier to trace.
Lightboxes are available in a variety of sizes and prices from most art suppliers. You can get an inexpensive 10"x12" table top model for around $35 all the way up to a free standing light table for $2,500. If you are handy you can certainly make one (instructions). In a pinch you can even tape your artwork to a sunny window or put a lamp under a glass top table.
Artists have been using grids for ages. It's intended to do two things at once - transfer and enlarge. The premise is that by laying a grid over your drawing you are breaking it down into smaller segments that are easier to re-draw. Start by drawing a grid on your sketch. Next draw another grid of the same proportions, but made up of larger squares. The last step is to re-draw your sketch square by square in the larger grid:
A grid works well enough but it is not as quick as the other methods mentioned here - you have to measure, rule out and draw two grids and re-draw the larger version. With the advent of photocopying, artists didn't need to use a grid as often. I include it here in case the electrical grid goes down and because it is still useful for large paintings and wall murals. When drawing on a large scale, it's easy for unwanted distortions to creep in. The grid helps avoid this. By the way, if you decide to take on a mural, get yourself a chalk line to make a wall sized grid.
Using a projector is another way to both transfer and enlarge an image. An artists' projector is an electric projector with a light bulb, mirror and lens. It projects opaque images (sketches, print photographs, etc.) onto any surface.
Start by placing your sketch underneath the projector (or on top depending on the model) and point it at your board or paper. You can adjust the size by moving the projector away from or closer to your board. Focus by turning the lens. The last step is to trace the projected image onto the board.
Artists' projectors are available from the usual art suppliers (Blick, Cheap Joe's, Jerry's Artarama, etc.) and range from $40 up to $600.
There are a couple of things to keep in mind when using a projector:
1) The size of a sketch or photo that can fit into an artists' projector is usually limited to 6"x6" or less. Most likely a sketch will be bigger and requires the extra step of making a reduced photocopy.
2) If you don't want any distortions in the image, it's important to keep the board or paper at a right angle to the projector - or as close to a right angle as possible.
TRANSFER QUICK LIST
Graphite Paper easy, ideal for boards, panels and papers that are too thick for a lightbox
Lightbox quick, clean; ideal for drawing and watercolor papers thin enough to let some light through.
Grid useful for large scale paintings and wall murals
Projector quick way to transfer and enlarge photos; good for unusual surfaces
Additional Information: You'll find the instructions for building a lightbox on a website called The Steampunk Workshop by Jake von Slatt. Besides the lightbox, there are two dozen very cool projects.
Artists have been using projectors for a long time. Longer than you might think. We know that Dutch artist Jan Vermeer (1623-75) used a similar device called camera obscura. The camera obscura projected an image of the surrounding environment by use of mirrors and lenses. In 2001 artist David Hockney and physicist Charles M. Falco published a book called "Secret Knowledge: Rediscovering the Lost Techniques of the Old Masters." They put forth the idea that advances in realism in Western art since the Renaissance were primarily the results of optical devices like the camera obscura. The book sparked intense debate among artists and art historians. Using an optical aid is disagreeable to non-artists. You'll hear things like "that's cheating" or "anyone can do that" - if that were true anyone could paint like Vermeer. To put it more directly, if a person can't draw a projector will not help them. If a projector can cut some time off of your work - use it. Use it and like the old masters - don't tell anyone.