Scaling Up A Photo

Puccini 16x20 oil

In painting portraits, one of the biggest challenges is achieving accurate measurements, because without precision, it is extremely difficult to arrive at a reasonable likeness.  There are myriad ways to measure when painting, with perhaps the most classic being to hold a paintbrush with thumb on handle and stretch your arm out toward the subject, measuring a distance - say, the width of a head - and then translating that distance to the canvas.  I have struggled with this method because it is hard to hold one's arm out at exactly the same distance each time and translate it to the canvas in exactly the same way, and so it involves much trial and error and I am often not happy with the result.  

When working from a photo reference, many painters will sketch out a grid over the photo and then sketch the same grid over their canvas, only on a larger scale, thus scaling up the photo.  But this method involves laboriously copying the marks and lines in each square, and for me, it doesn't feel much like drawing naturally.  Also, it requires that you print out the photo or else create a transparent sheet with a grid on it that you can tape to the front of your computer screen.  Since all the photos I work with these days are digital and I almost never print something out, this approach just feels too cumbersome.

There are specialty dividers one can buy or make, so that you measure the distance on the subject and the dividers automatically make the other end of the device some increment larger, but I have to admit I have never tried this method.  I might one day make up a set of these dividers in the shop, but they seem unnecessary when I have my go-to method already available.

In painting portraits from photo reference, I almost always rely on an engineer's scale - that triangular ruler that you can find in an office supply store.  It has six scales -10 through 60, and I used it in the past to draw plat maps for building projects.  A building lot is usually too large to use an architect's scale - those with 1/8"/foot, 1/4"/foot, etc.  and the engineers scale allows each inch to represent 10 feet, or thirty feet, or sixty feet, meaning you can get a big plot of land on a small piece of paper.

But for scaling up a photo, I find it is just as useful.  The first step is to crop the photo to make sure that the aspect is the same as your canvas.  For example, if you are using an 8x10 board, make sure the photo is cropped to an 8x10.  Then you need to find which scale comes closest when you measure it on the computer screen.  Most photo software will allow you to enlarge the image in small increments, and I typically begin by holding the engineer's scale against the image and enlarge it until the width matches the width of my canvas.  Once I get it to the right size, I can begin to transpose those measurements I want.  For a portrait, I usually want to find the placement of the major features of the face, so, for example, I put the zero mark of the scale at the bottom of the chin and make note of where the scale hits the top of the image.  I then transpose this measurement to the canvas.  For a portrait, the most important measurements for me are the chin, the top of the head, the mouth, bottom of the nose and center of the eyes.

Working from one side of the image, I measure for the sides of the head, the center of the nose, the width of the mouth and the side of each eye.  If you want to find the exact placement for any particular point, you can measure from the top and from the side and make a mark for that point on your canvas.  

In this case, I was using the 30 scale, meaning that when I transferred the marks to my canvas I was increasing the measurement by three times, since I switched to the 10 scale for marking the canvas.  (I try to use a red pencil for drawing because it doesn't dirty up the paint like a graphite pencil will.). Once I have located my major points of reference, I can sketch in the entire head, and then if something seems off, I can double check it with the scale to see where I am wrong.

I find that locating only the critical points helps me to quickly avoid gross errors and yet allows me to sketch more naturally for the majority of the face.  Often I will skip the measurements entirely and just sketch first, only checking with the scale if something seems off.  I feel that having done this repeatedly over time has strengthened my ability to sketch accurately without measuring, but it is not something that happened overnight.  Miles and miles of brushwork....

Once I have the basic sketch, I can begin painting without the fear that I will have to go back and try to move features around once the paint is down.  A quick block-in covers the canvas.

For this painting I used a limited palette of cadmium red light, gold ochre, ivory black and white.  I used Neo megilp instead of Liquin as a medium in order to leave the paint open to blending for a longer period, but now I want to wait for it to dry so I can go back to it and make corrections, since inevitably, the likeness is still off.

A final note:  if anyone decides to get an engineer's scale and try this for themselves, I should add that sometimes it is hard to find a scale that works for your canvas, and one trick I have found is that you may need to scale from 50, say, to 20 instead of 10.  That allows you to increase the measurement 2 1/2 times rather than just two or three or four.  You might need to scale from 30 to 20, or 60 to 50, or whatever works.