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DPI for A1 paper size?


Senior Member

I'm going to be printing a few A1 sheets with black and white content ( building plans )... I was wondering how many dots per inch I should save it as ( I use ArchiCAD and you export as a PDF and can choose the DPI ) I normally go with 300DPI but that's when I print A3 and since I've never used A1 I'm not sure what settings would work better. The printer I will be using is a HP inkjet ( don't know the model number )

Also, does a colour document need the same as a black and white document, in terms of DPI ?

Thank You


Well-Known Member
It depends on how sharp you want the image and how much detail needs to be visible.

A 300dpi image saved at A1 size is just as sharp as a 300dpi image saved at A3 size. It's dots per inch, not dots per page.


Senior Member
What HP printer can handle a1?

If it is being handled by a printer ask them. I have noticed that you can get away with a lower dpi at larger sizes, but it does depend entirely on how close who ever is looking at the print out is going to be.

Can you make it vector?


Senior Member
Oh yes of course, it's not related to paper size it's inches !

I don't really need to make it a vector because a PDF holds enough detail...

Thank You

Oh and it may be a HP Laster printer ? I'm not sure, it's at University.. they have 3 all equipped with colour toner/ink and paper rolls... oh and a cutter of course :) and they charge a fraction of what somewhere like Staples do ( plus they print larger, you just have to wait for the print queue before you can get your work.


it'll probably be an HP Laser Plotter as they had them in University when I went (all the way back in 1999 :eek: ) :)


Senior Member
Yes it's a Plotter... Not from the 1990's though, the University has only being there 10 years and it doesn't look that old.


Staff member
plotters don't usually use dpi, they normally use nibs to 'draw' lines.

They should be able to work natively with autocad or similar file formats and scale accordingly.

If it's a large format printer my experience with plans says 150-300 dpi minimum to get crisp lines, colour and greyscale should be treated the same in most cases.


Senior Member
Ok, I'm going to Uni tonight so it should be quieter...

Do larger files in general take longer to print that a file that is much smaller ? I'm not sure if it is to do with the file been sent to the plotter which is dependant on the network speed...

Thank You


Senior Member
great ! Still, I'm going at 7am tomorrow to print... the building is open 24hrs !

Also, when I open a 1200DPI PDF in Illustrator, the lines are still slightly jagged, how can I convert it to a vector ?

P.S Do you know where I can find VECTORS ( human figures ) for Illustrator that I can use with the brush tool if that makes sense... I've downloaded some but Illustrator says the file in not a know format.

Thank You