Sometimes when you scale an object, you later want to change it back to the original size. The easy way is, of course, to use Undo (CTRL or CMD Z). Naturally, the need usually becomes obvious after several other changes have been made and you don’t want to undo all of them. If you happen to remember one of the original dimensions of the object, you could just type in the width or height in the control panel (make sure that the width to height link control is set on). If you don’t know the original dimensions but you do remember the scale factor you used, you can use the complementary scale factor to scale the object back to the original size.
If you had scaled a shape by 80% and then needed scale it back to the original size, you would use 125%. Even though 120% may intuitively seem to be the correct value, it would actually be too small. Here is how you find the complementary scale factor:
Divide 100 by the 80 (the original scale change) and multiply the result by 100.
(100 ÷ 80) × 100 = 125%
You may use the decimal percentage value by dividing into 1 (one) instead.
(1 ÷ 0.80) × 100 = 125%
This method also works to scale artwork back down to the original if the original scale factor was larger than 100%.
If the original scale was 300%, you would do
(100 / 300) * 100 = 33.333%
Avoid going back and forth with values this way, especially when the values have decimal values. Rounding errors will eventually build up and make noticeable changes to the size.
Please leave a comment, cheers!