enlarging scaled design

[MustangSally]

I have a landscape design at a 1:15 scale. I would like to enlarge it for ease of design purposes while keeping the scale comparable so that when finished, I can then reduce the design back to the original scale/size. I use the equipment at FedEx and they try, but I usually get blank stares. I need to know the % to enlarge the original, I can only assume I would then use the same % to reduce the enlargement to reproduce the original.

 

[Dr.Peterson]

I have a landscape design at a 1:15 scale. I would like to enlarge it for ease of design purposes while keeping the scale comparable so that when finished, I can then reduce the design back to the original scale/size. I use the equipment at FedEx and they try, but I usually get blank stares. I need to know the % to enlarge the original, I can only assume I would then use the same % to reduce the enlargement to reproduce the original.

It isn't clear what you want. How much do you want to enlarge it? Does "comparable" mean "not too much larger", or perhaps something like "compatible", such that it can be reduced to the original scale easily? Does that include consideration of how the enlarged copy will fit on a sheet of paper?

The trouble is, you have to reduce by a different percent than you enlarge (unless the equipment somehow has a setting to undo a percent enlargement). I'd like to see what options the equipment you're using has, especially if it has only a specific set of percentages, which would make this trickier. Do you know the kind of machine, so we could look up its specifications?

 

[JeffM]

The percentages will differ. If you go to 1:12 from 1:15, that is an increase in linear scale of 25%. When you reduce back, that is a reduction of 20%.

Computation of percentage increase:

[math]100 * \left \{ \left ( \dfrac{1}{12} \div \dfrac{1}{15} \right ) - 1 \right \} = 100 * \left ( \dfrac{15}{12} - 1 \right ) = 100 * (1.25 - 1) = 25.[/math]
Computation of percentage decrease:

[math]100 * \left \{ 1 - \left ( \dfrac{1}{15} \div \dfrac{1}{12} \right ) \right \} = 100 * \left (1 - \dfrac{12}{15} \right ) = 100 * (1 - 0.80) = 20.[/math]
Given that you are using 1:15, you will get exact percentages only if you go to 1:12, 1:9, 1:6, or 1:3.

 

[MustangSally]

It isn't clear what you want. How much do you want to enlarge it? Does "comparable" mean "not too much larger", or perhaps something like "compatible", such that it can be reduced to the original scale easily? Does that include consideration of how the enlarged copy will fit on a sheet of paper?

The trouble is, you have to reduce by a different percent than you enlarge (unless the equipment somehow has a setting to undo a percent enlargement). I'd like to see what options the equipment you're using has, especially if it has only a specific set of percentages, which would make this trickier. Do you know the kind of machine, so we could look up its

The percentages will differ. If you go to 1:12 from 1:15, that is an increase in linear scale of 25%. When you reduce back, that is a reduction of 20%.

Computation of percentage increase:

[math]100 * \left \{ \left ( \dfrac{1}{12} \div \dfrac{1}{15} \right ) - 1 \right \} = 100 * \left ( \dfrac{15}{12} - 1 \right ) = 100 * (1.25 - 1) = 25.[/math]
Computation of percentage decrease:

[math]100 * \left \{ 1 - \left ( \dfrac{1}{15} \div \dfrac{1}{12} \right ) \right \} = 100 * \left (1 - \dfrac{12}{15} \right ) = 100 * (1 - 0.80) = 20.[/math]
Given that you are using 1:15, you will get exact percentages only if you go to 1:12, 1:9, 1:6, or 1:3.

Thanks JeffM.
Yes Dr Peterson, you were correct, I meant compatible. No, normally the rolls used at FedEx will handle up to a 200% increase easily, little awkward to roll up and get on the drawing board...I am not a math person therefore this is the most frustrating part of my design work. I am considering hiring a tutor to help this old brain of mine struggle through these formulas. Thanks y'all!