Pixel Size and Memory

[kayoy]

Hi All,

Finally getting started with Digital. We're planning to create Large Posters.

Does anyone know how much memory a certain number of pixels consume?

We'd like to print 36 x 48 inch Posters at 300 dpi.
I think that's 10,800 X 14,400, so how many Megabytes would that be

If anyone knows how to compute, we'd feel less scared of crashing our computers.

Thanks,
Carol

[Franglais]

Hi All,

Finally getting started with Digital. We're planning to create Large Posters.

Does anyone know how much memory a certain number of pixels consume?

We'd like to print 36 x 48 inch Posters at 300 dpi.
I think that's 10,800 X 14,400, so how many Megabytes would that be

If anyone knows how to compute, we'd feel less scared of crashing our computers.

Thanks,
Carol

One pixel (from a normal 8-bit JPG) is 24 bits = 3 bytes.

So you're looking for 10,800x14,400x3 = 466,560,000 bytes

Divide by 1024 to give KBytes and again by 1024 to give MBytes = 445MB

If you use Photoshop to print the image then this commonly needs 3x the size of the image in RAM. Plus you've got the spooler and the system.. It looks like you need a system with 2GB of RAM memory at least.

Are you sure you need to print at 300dpi? Where did you get a 445MB image from?

Charles

[another view]

At a given pixel dimension, the file size will vary a lot depending on whether the file is a TIFF, RAW (but what camera makes a file like this?!) or a jpeg - and in that case what the jpeg compression is set at.

I remember your previous posts - have you tried printing at less than 300dpi? If these posters are of a single image and you're not using a 155 megapixel camera, then you're interpolating up to that size anyway.

[kayoy]

Thanks for your replies guys.

Now it's time for me to actually do test runs, so here goes.

I'll post my actual "findings"