Convert an image containing a scale indicator into a multipage PDF

to obtain actual dimensions on A3 sheets

Image with scale indicator

If you have an image with an element with a dimension in cm (e.g. a dimensioned drawing, a template, a sewing pattern, etc.), size the image to actual size on A3 sheets.

We assume that the given dimension is parallel to the edges of the image. If several elements are dimensioned, choose the largest, which we call the “scale indicator”. This sets the working direction: we compare lengths either horizontally or vertically.

In practice, you need to display the image on a screen or sheet of paper in such a way that you can clearly see the four edges of the image (i.e. its frame), then take measurements with a graduated ruler. To achieve sufficient precision, these measurements should be taken on a fairly large image.

  • the height or width of the scale indicator in the image is measured in cm on the image (not to be confused with the length the control should have);
  • the image height or width is measured in cm across the image, from one edge to the opposite edge.

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(but not PDF).

A large image produces a large PDF. To obtain a lighter PDF, if you accept a lower image quality, resize the image.

 

, measured on the screen image or on paper :

(height of scale indicator in image) / (image height)

or

(width of scale indicator in image) / (image width)

The measurements were made

To avoid printing flush with the edges,

 cm

During treatment: a little patience.

Save the document to download in PDF format,
e.g. actualsize-a3-01.pdf

Print margin

Margin 0 can be entered if you don't mind missing parts of the image near the edges of the sheets. This will facilitate assembly, as entire sheets can be juxtaposed.

Print

In your printing software, select A3 paper size, automatic orientation and “Actual size” or “100%” dimension.

Adjustment

Due to inaccuracies in the height or width ratio measurements, the actual measured value m may differ slightly from the prescribed value c1. To correct the data, leave the height or width ratio unchanged and enter the corrected cm dimension c2 calculated as follows:

c2 = (c1)2 / m

Cutting

To cut out the photo, use a cutter, a cutting board and a ruler. To juxtapose two photos, cut on the 0.2 mm white line between the partial photo and the black frame.

Variants

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