Scale conversion with photocopier

François -
didmed Posted messages 2654 Registration date Status Member Last intervention - 5 Sep 2015 at 16:39

Hello,

I have a drawing in A4 format, at a scale of 1:500.
I would like to reproduce it in A3 format, at a scale of 1:200. Also, consider at a scale of 1:100 if it works.
Does anyone know what the enlargement percentage is, please?

Thank you very much,

François

2 answers

Answer 1 / 2

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didmed Posted messages 2654 Registration date Status Member Last intervention 845

Hi.

When moving from A4 to A3, the ratio is:
[x square root of 2] or [x 1.414]
This applies when moving from A5 to A4, A3 to A2, A2 to A1, or A1 to A0.

For the scale, it’s different:
to go from 1/500 to 1/200 (enlargement), the ratio is:
[500/200] or [x 2.5]
to go from 1/500 to 1/100 (enlargement), the ratio is:
[500/100] or [x 5]

So when moving from A4 to A3, the scale enlargement ratio is:
[500/1.414] or about 1/354.

You can go from 1/500 to 1/200, but you'll be missing some information...

@+

--
If you need anything, just let me know!...
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Answer 2 / 2
contrariness Posted messages 17905 Registration date Status Member Last intervention 6 244

It should be checked, but it seems to me that photocopiers give enlargement percentages in area rather than scale.

Changing from A4 to A3 means increasing by 200%. In this case, we need to redo didmed's calculations to find the scales of the drawings.
2
1. didmed Posted messages 2654 Registration date Status Member Last intervention 845
  
  Hi Contrariness.
  
  "Switching from A4 to A3 means increasing by 200%" > I disagree.
  If there is a line of 100 mm on an A4 sheet, when enlarging it to A3 it would (according to your statement) be [100 + an increase of 200%] which is [100 + 200] or 300 mm
  
  However, when going from A4 to A3, the increase is [100 x square root of 2] which is [100 x 1.414] or 141.4 mm > So the increase is 41.4%
  
  In any case, when switching from one format to another, it's the square root of 2 factor (1.414) that applies (the ratio between the length and width of the format that remains constant)
  
  Otherwise, your cat is very beautiful!!
  
  @+
  
  0
2. contrariness Posted messages 17905 Registration date Status Member Last intervention 6 244
  
  Hello Didmed
  
  I agree with you.. but copiers often have a display with a surface indication.. so if an A4 is 100%, doubling the surface means multiplying by 2, so 200% (IMHO, it's also because the displays can't show decimals!)
  
  For the scale of dimensions, your calculation is correct... The logic in "office work" can sometimes be weird!
  
  Thanks for the chat.. lol..
  
  0
  1. didmed Posted messages 2654 Registration date Status Member Last intervention 845 > contrariness Posted messages 17905 Registration date Status Member Last intervention
    
    Re
    
    Copiers have 2 types of calculations for automatic enlargement/reduction:
    1- by formats (going from A5 to A4 or from A4 to A3) and in this case, the factor 1.414 applies > you double the area (that's true!) but multiply by 1.414, so the auto zoom from one format to another is 141.4% (and not 200%)
    2- by % > if you have an A4 document, apply 141.4% and if the copier has an A3 format, the copy will come out on an A3 > the area will be doubled (that's correct) but the factor will not be 2 (200%) but 1.414 (141.4%)
    
    I speak from experience > I was an office technician repairing copiers (A4-A3) but also copiers and plotters for plans (A4-A3-A2-A1-A0)
    
    I might even still have some PDFs like 'user guide' for copiers...
    
    @+
    
    0

Scale conversion with photocopier

2 answers

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