Having picked out just the right photo I sent the file off to be printed. I chose to have it enlarged to 30 x 45 cm, so I'd have clear detail to work from and could place a good-sized grid over it to simplify enlarging it into a drawing on even larger paper. Am I being clear? - probably not! - but you'll see what I mean as I go along!
I waited, somewhat impatiently, for my photo to be printed and delivered to our local supermarket, where we could pick it up. It only takes a couple of days, but when I'm waiting to get started with the drawing of a once-decided-upon subject, 2 days feels like forever. I'm not the most patient person in the world once I've decided something! Anyway, Saturday arrived and the photo was ready to be picked up. I couldn't wait to open the envelope...yes, this was gonna be a good one (I hope! - no pressure, don't you laugh if it doesn't work out!).
I have a slightly primitive but very effective method of getting drawings from photos to scale on a large piece of paper. As I said, my photo was 30 x 45cm (approx. 11.8 x 17.7 inches) and I was intending to make a drawing with a decent margin on a piece of paper which was 80 x 60 cm (approx. 31.5 x 23.62 inches).
I also have a grid with 6 cm (approx. 2.36 inch) squares drawn on a large piece of clear cellophane.
I took the cellophane and wrapped it around the photo, so that the squares lined up with the edges of the photo. This left a column of partial squares to the right of the photo which I will leave out of the drawing. My image will therefore be 7 squares x 5 squares in total.
The next step is to draw 8.5 cm (approx. 3.35 inch) squares on my large piece of paper. I draw 8.5cm squares (7 x 5), centering them on the paper. My grid is 59.5 x 42.5 cm (approx 23.43 x 16.73 inches).
Here's the sum to centre the grid:
80-59.5 = 20.5, divided by 2 for the margins left and right = 10.25 cm
60-42.5 = 17.5, divided by 2 for margins at the top and bottom = 8.75 cm.
left and right margins are 10.25 cm (4.04 inches)
top and bottom margins are 8.75 cm (3.44 inches)
7 squares across of 8.5 cm (3.35 inches)
5 squares down of 8.5 cm (3.35 inches).