8 Meters x 2.5 Meters wall at 100 DPI

In way of explanation, the limit is 300,000 pixels in any direction. So the example shown by digital dog of 7620cm x 100ppi equates to 7620/2.54 x100 = 300,000 pixels.

When you tried to enter 8000cm at 100ppi then you were asking for a pixel dimension of 314,960 pixels which is over the maximum limit. So if you did need an 80 metre wide document then you would need to reduce the ppi.

Dave

What Dave said. You can enter an accepted value by 100dpi, but 8000cm isn't allowed as seen below.

Just change this to the value you want; 800cm@100dpi.

' .....PS does not allow me to input 8000cm in the width slot (it turns red).... '

8 metres is 800cm not 8000cm

Dave

Just do the math, or let Image Size do it for you.

800 cm at 100 ppi is 31496 pixels. Photoshop doesn't care about physical size, just pixel size.

So this is a big file, but no problem for Photoshop as long as it has the resources to handle it. That means, most importantly, scratch disk space. This is a huge amount of data to move around, and all that data has to go somewhere.

I'd recommend 1 TB free disk space for this. If you can put that on a fast NVMe drive, this should be perfectly workable. Without enough scratch disk space, this will not work.

InDesign is a vector application that works on different principles. InDesign does have a physical size limit (off the top of my head I think it's somewhere around 6 m).