View Full Version : Help with setting DPI

11-21-2009, 06:08 AM
I am a little confused about DPI/PPI. I did read the other post and even followed some of the links but I still had a few questions.

I want to design a continent or multi-continent map that I would eventually have professionally printed. The print media has a maximum size of height 48" and width 96". I don't think I will be designing a map that is twice as wide as is long so essentially, I will likely finalize the map as a 48" square. I understand that I want 300 DPI for printing a quality reproduction. By my calculations, I would need a document 300 X 48 = 14,400 x 14,400 pixels. Creating such a file in Photoshop 7 is memory intensive and working with a file half as big is slow. Does this sound right? If so, how do designers and artists work with such huge files?

Thanks in advance for any insight, comments, etc...

11-21-2009, 10:25 AM
Most of the time, an image that size is a banner or poster, and it's typically a vector image, done in Illustrator or Inkscape. I've only designed one poster-sized map, and it was done in Illustrator.

You don't necessarily need 300 dpi in a print that size. Consider the estimated viewing distance when setting up your document. If the map isn't intended to be viewed at arm's distance or less, then you can reduce the resolution accordingly.

By the way, 48" square is huge. You may want to give yourself a reality check by actually laying that out and seeing if you need it to be that big. My poster print was, I think, 36" x 24", and that was about the right size for a good poster map. It could be unrolled on the table without going off the edges or hung on the wall and viewed from several feet away fairly easily. And since it was intended to be viewed from a fair distance, I exported it at, I think, 200 dpi, making the rasterized file 7200 x 4800, which most reasonably modern computers can handle.

11-21-2009, 10:55 AM
Are you sure you want 4' x 8' sized map, that really hugh! I digitally print maps at my print studio, Gamer Printshop, but even my printer is limited to 42" wide, so I can do a 42" x 96". Still that's gargantuan. That $83.72 for just the print. Unfortunately I can only laminate 36" wide, so I couldn't do one the size you're looking for.

While its true I've created maps this large before for a client, I've only done it once. That's crazy big. DPI wise, you would only 200 ppi, depending on how small your text size is, that's where resolution matters the most.


11-21-2009, 07:14 PM
The DPI you need depends on how far away you want to view it. If your spreading it out on a table and look at it like you would look at any other page or book then 200+ is what you need. As a poster tho you can go less.

From a tech point of view images much bigger than 14K start to get unwieldy. Some image file formats can start to have issues at 16K but you would most likely see it slow down a lot. BMP and PNG seem ok at 14K but past 20K its iffy.

I deal with images up to about 14K. I would probably have tiled it before then tho. Maybe at 4K squares or 8K squares. So you could do a map as 4 squares of 8K x 8K. You just have to ensure that the overlap is seamless.

I have the main MeDem map at 20K square which is 10x10 of 2K tiles. This map is not entirely manually made tho.

11-22-2009, 12:31 PM
Thanks for the info. I for sure will have to scale it down. Maybe half the size to 24" x 24". My main goal is to have a player useable map with a lot of detail up close. An alternate size would be 30" x 36". I also plan on the printing on vinyl or some non-standard paper media.