Maximum image size to be printed on both A4 and Letter paper sizes

Question

I want my documents to be able to be printed on A4 (210×297 mm) as well on Letter (8.5×11 inches) paper. (The "documents" are TIFF files with raster text on them. This is important to me. Being in Europe, I can send such a file to my friend in US, and he would be able to print it on Letter instead of A4, without any troubles.) Does it mean that the safe size of the image is 558×756 points (7.75×10.5 inches, 2325×3150 px at 300 dots/pixels per inch), or there is an error somewhere?

Math:

A4: 210 x 297 mm => a little less than 595 x 841 pt
I like to reduce 595 to 594,
because 594 is exactly 8.25 inches

Letter: 8.5 x 11 inches => 612 x 792 pt

So,
A4 x Letter = 594 x 792 pt

And then we need to subtract about 0.25 inches, that is,
18 points on each side for non-printable margins,
which gives 558 x 756 pt (7.75 x 10.5 inches),
which is 2325 x 3150 px at 300 dots/pixels per inch.

Answer 1

IMHO There are some misconceptions in appreciation of the problem. Let me throw some randomly.

PPI

• 300PPI This is a round number where it is double the literature capable of the printing systems, generally used for offset print. If your project is not to be printed in those systems, you do not need 300PPI.

• Even if you actually are going to use those systems, you can use a smaller number. 212PPI

• For an error diffusion print, for example, an Inkjet you can use 200PPI

• To really have a grasp on the proper PPI, you could make some tests and get some feedback from your partner.

• If the image is 1 bit, you could go as high as the DPI of the printer. 600-1200PPI so each pixel matches a Dot. Depending, again of the printer.

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Physical size

I would not use 3 different dimensional units! Stick to 1. I'll use cm. And after all operations, you can then transform them into whatever you need.

• A4 > 21.0 x 29.7 cm
• Letter > 21.6 x 27.9 cm

The first answer is. Use the smaller number on each axis. 21.0 x 27.9 cm.

The second answer is if you really know the margins of the printer. A simple number can be, just reduce by .5cm on each side. 1cm on each axis. It is just a wild guess.

The third answer depends if you are allowed to stretch the file (deforming it a bit) You probably can use the bigger number 21.6x29.7cm and just stretch to fit.

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Another option

But if you want a proper print, to somehow maintain the real scale as much as possible, prepare two documents and do not send a TIFF file, but a PDF with the TIFF file inside.

PDF software normally is "less lose" when interpreting how to print a file, so there you will have a "Do not fit page" "Do not scale" or "use Real size"