need help with a photoshop project.

[Arizon]

So i'm going to make this photoshop project for my parents which is later going to be sent over to some other guys to get it printed and so on..

Well, i need some help with this, i know how the design is going to be, but the guys that are going to print it, says this:

It has to be 800 mm in width and 2100 mm in length (no idea why they use mm, but oh well.)
There has to be a white edge at the top which is going to be 40 mm and a white edge at the bottom which need to be 100mm

They also mentioned something about the pictures needing to be atleast 300dpi.. (These pictures are taken by professionals, so i'm sure the pictures are good enough :P)

Of course i know how to make the project and stuff, but i need some help on finding those edges at the bottom and the top and making them accurate.
if you could please just quick explain what they mean by 300 dpi, that would be just great!

This is going to be printed as a roll up... i believe its called.. btw.. :P

thanks in advance

[shadowlich]

When you make a new project it lets you select the quality, it it has to be at a minimum of 300dpi I guess.

[Deleted]

with 300 DPI, they mean Dots Per Inch. basically, it concerns the relationship between the dimensions of your picture in pixels, and the poster that it's printed on in metric or imperial system

in this case: you got 800mm (an inch is 2.54cm), or 31.50 inch, by 2100 mm, or 82.68 inch. 31.50 inch with 300 dots is 9,450 pixels wide, and 82.68 inch is 24804 pixels tall. so basically, your image needs to be 9,450X24804px. any more or less, and you're going to lose quality.

edit: that, and the person above me, but it basically comes down to similar prospects.

[Symphonic]

File -> New

it will ask you what dimensions your project will be. You can adjust it to be mm instead of pixels or inches if you'd like.

(800mm is 3023.6 pixels, 2100 mm is 7937 pixels)

Then you adjust the resolution to be 300 DPI. then you click on okay. and it makes a new blank image. If you chose to have a background and you made it white, then there ya go.

40mm is 151.2 pixels. 100 pixels is 378 pixels.

I think you'll be able to figure out how to get those edges.

(Once you change the resolution to 300 DPI it adjusts the size to reflect that you're not working on 72 dpi, which the above poster is correct, it's 9450 x 24805 pixels