Someone on an Aussie list asked for the formula for enlarging patterns. I replied, then thought more
of you might want this info to save.
I included what to do with the number you get after you do
the math. This also works when printing from online, if they
include a 1" or some other scale to check your size. I'll add that
calculation at the bottom. (I am likely to type something wrong, so
if you catch it, please respond to the lists so we can all correct
it!)
The original question gave the example of how large to make it if it
is 75% of the original. I said that SD&A said 134%, but that I
didn't see how. Then I did the math:
The math formula as given to me by my brother The math formula as given to me by my brother
Divide what you want by what you've got. Oh, heck, I did the math
and they are right, it's 134%, LOL!!
Okay, it's like this:
You want 100%, you've got 75%. 100 divided by 75 = 1.33333 
enlarge by 134% (set your copier at 134% or if using computer,
multiply the pixel sizes by 134% and enter them in the width and
height boxes)
You want 18 cm, you've got 14 cm. 18 divided by 14 = 1.285 enlarge by 129%
To reduce
You want 14 cm, you have 18 cm. 14 divided by 18 = .777  reduce
to 78% (set copier at 78%, or if using computer, multiply the pixel
sizes by .78 and enter the results in the width and height boxes)
You don't have to understand it to be able to do it, just write it
down, "divide what you want by what you've got."
If you have a 1" mark to work with, first measure it to see what it
printed out at. It is easier if your turn the fractions into
decimals. I only know the easy ones off the top of my head. Use
the one closest to the mark and it should be close enough when you
finish.
1/8" =.125
1/4" = .25
1/3" = .33
1/2" = .5
3/4" = .75
Enlarge:
You want the mark to be 1", your mark is 2/3" (.66) long 1 divided
by .66 = 1.51 Set the copier to 151% or multiply the width and
height numbers by 1.51
Reduce:
You want the mark to be 1", your mark is 1 1/4" (1.25) long. 1
divided by 1.25 = .8 Set the copier to 80% or multiply your width
and height numbers by .8
As I said, you don't have to understand it, just print this and put
it with your dolly stuff, then take it step by step when you need to
enlarge or reduce.
Aileen Fish
