Expert: Scotto - 4/29/2011

Question
I have an item that I have scaled down to 60% it's original size. I want to scale it back up to it's original size, but when I try to do that with my computer program, the new, smaller item is set to a new 100%. I have tried increasing it by 140% but since it's a different size, the extra 40% is of the smaller size, and not the original, so it is incorrect.
Does this make sense? If you know a formula I can use to fix this, I would greatly appreciate it.

Thank you,

Nancy

Answer
I'm not sure such equipment can restore items to the original size.
If something is taken from size x to size y, the size is changed by y/x.
To change iit back, it needs to be changed by x/y.

See, if both of these changes in size are involved, they are multiplied together,
canncelling each other out, since there is a y/x multiplied by x/y.

Unfortunately, when size is changed to a 40% smaller size, it needs to be increased by 1/40% =
5/2 as large as it was.  That was fairly easy.  However, if it was just reduced by 10%, it is now 9/10 of its original size.  To change it back, in needs to be multiplied by 10/9 of the current size.  In fraction form, that is 1.0909090909...  In reality, 1.09 would work, but it would still be a slight amount smaller.

If the page were 8.5" x 11", the copy being reduced by 10% would be 7.65" x 0.0".
If it were then increased by 1.09, it would be close to the same size,
The new dimensions would be roughly 8.3 x 10.8.

What they need to do this properly is a copy machine that accepts fractional values and converts several digits.  This could also be done if the copier asks you if what you're copying is the original or a copy.