[EMAIL PROTECTED] (2002-10-11 at 0037.23 +0200):
> At 300 dpi, it seems I have to create an image 9933 pixels wide by
> 14043 pixels deep (A0 being 33.11 x 46.81 inches), forgetting the
> margins for the moment. That's 140 megapixels, or about 3 gigabytes
> in 24bit colour. I fear my machine would be swapping until Doomsday.

Uh? What kind of maths do you use? Seems you have a problem with
megapixels and mega/gigabytes. 9933 (pixels) * 14043 (pixels) * 3
(bytes/pixel) = 418 467 357, around 400MB, never 3GB. You do not
multiply by 24, but by 3, the number of pixels you have. 3 bytes,
being each one composed of 8 bits, gives 24 bits. Computer RAM and
disks use that same unit currently, bytes made of 8 bits, not the
plain bits.

> Dropping it to 75 dpi works out at about 9 megapixels or about 200
> megabytes - much more manageable, but will it look any good?

At 75DPI you have 2484 * 3511 * 3 = 26 163 972 bytes, around 26MB. Of
course, as soon as you add the app, the layers, the data for things
shown in screen, the rest of the OS and apps, you require more, but
that is when you are already working, not just to start.

At 150DPI, a computer with 512MB is going acceptably, the image is
108MB. If you go for 200DPI (or better, ask which is the range the
printshop machines handle without giving bad results, and make sure
you get the number of pixels per inch of the image, not the dots per
inch of the printer) for a poster, you require around 185MB for the
image. A computer with a GB or more should be fine to work in it.

And after doing all the maths, I realized Gimp can be used as a
calculator for this with the new image dialog. Set the inches (or
whatever unit you have, A0 is more mm friendly), set the DPI (read it
as pixels per inch, or "image file dots") and it tells you the size of
the base layer.

> What do other people do for poster-size work?

Start with original images at the required size or use vector
graphics, for example.

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