If you are using a photograph for reference, you will need to make a print of the picture to the desired scale, and then trace the pertinent guide lines from that print.
Even if you are making a freehand drawing, not using a photo, you don't want to damage the surface of your drawing paper by drawing, erasing, redrawing, and adjusting the objects included in the picture until you get the perspective you want. This should be done on a separate sheet of paper and then the needed outlines traced to the drawing paper for coloring.
Transferring Techniques
1. Light Table – Place the drawing paper on top of the re-sized picture, tape to a light table, then lightly trace the needed outlines. During daylight hours, a plain glass window can also be used in place of a light table, provided the glass is dry.
2. Carbon Paper - This is a lightweight paper coated on one side with a dark waxy pigment. The carbon paper is placed on top of the blank drawing paper, and the re-sized picture is taped on top, so that the drawing paper will receive a copy of whatever is traced over on the top sheet. The drawback to using commercially sold carbon paper is that the image that is transferred onto your drawing paper is not easily removed and could damage your paper.
3. Homemade Carbon Paper - Using a photocopy image, the desired size of your intended illustration, color the back with a carbon pencil. This is the method that I prefer for transferring images to my drawing paper. It's quick and accurate and the pencil lead is easily erased when the guide lines are no longer needed. The only drawback is that a light touch is required to prevent smearing carbon onto the drawing paper.
4. Grid Method - Rather than getting the original print to the desired size and then tracing it, it is also possible to re-size the picture to the drawing paper using the Grid Method. This is done by drawing a grid of squares over the original photo, then lightly drawing a grid of an equal number of squares onto your drawing paper, and finally sketching the drawing into each square, matching what is seen in the original photo. This is a tedious procedure that I do not recommend. I'd rather spend more time and energy on the fun part with the colored pencils.
5 Easy Steps Transferring the Image: Once you have selected the picture you wish to draw, you will need to place guide lines of the general outline of that picture onto your drawing paper. The guide lines will be erased as the drawing progresses; however, they are necessary in order to maintain the size, shape, position, and perspective of the various objects in your drawing.
Step 1: Making a photocopy
The maximum size paper that my printer uses is 8 1/2" x 11". Most of my illustrations are much larger than that. So, I must print several sections of the photo and piece them together. When I print them, I make sure that they are all enlarged the same percentage and that the images will overlap each other. I trim the excess paper and tape the pieces together.
Step 2: Applying the Carbon
On the back, I fill in with a carbon stick. (I use a number 2 lead because it's dark enough to see the image, but not so soft that it leaves dirty smudges.)
Step 3: Taping the photocopy to the drawing paper
This step sounds simple enough, but it's important what type of tape is used. If you use regular scotch tape, removing the tape could damage the paper. I like to use Drafting Tape (NOT Masking Tape). Other types of tape may be used, so long as they are not too sticky, and can be easily removed. Just to be on the safe side, I try to leave enough paper around the image so that the tape is in an area that will not be used or seen in the illustration.
Step 4: Tracing the outlines of the picture
I use a hard lead pencil to trace the outlines of the image, usually a 4H. If you don't have a 4H pencil, I wouldn't go out and buy one. A regular 2B works, but I like the thinner line a harder lead pencil makes on the paper. If you use a soft leaded pencil, your lines will be wider and sometimes that makes your image less accurate.
The pressure you use is a very important detail in this step. You want to use enough pressure to be able to see the image, but you don't want to use so much pressure that it creates grooves in your drawing paper after the guide line is erased. Colored pencils will not penetrate these grooves and the objects in your drawing will all have white outlines. (Important tip: You don't have to trace every single detail. You are only wanting to transfer enough so your image will be in perspective and you have a clear view of what you are creating.)
Step 5: Removing the photocopy
Carefully....slowly.....carefully....remove the tape. (Did I mention carefully? Well, I'm saying it again, CAREFULLY remove the tape.) You certainly don't want to retrace everything again on a new piece of drawing paper because of torn and damaged surfaces.
Now the fun begins!!