need a few advices on resolution needed for large format printing

hello,
first, sorry if this is posted in wrong section, but i really don't know much about printing.

anyway, i want to make a photo wallpaper for my wall (dimensions 360x240cm).

what is the minimum resolution of photo i could use?
what about dpi?
how can i be sure how the image will look regarding color balance and saturation, cause it seems that these parameters are different when i open the same image with two programs, e.g. photoshop and irfanview?

any additional info/advice would be appreciated.

thanks in advance

 

Depends on the output device...I guess you're outputting to an wide body inkjet printer so you'd need minimum 350ppi resolution in your image. Most inkjets will mask any deficiencies in the file on output since they aren't as demanding as imagesetters or platesetters for litho print.

As for being sure of the quality of output ... why not have a proof of a section of your job in A4 size? That should be cheap enough and will allow you to make colour judgements and if necessary amend hue/saturation etc.

 

thanks for your reply.

as for the bolded part, i don't really know how to do it.

i guess i should first set the printing output of image to desired dimensions (360x240cm), then divide it into sections of A4 size, but i have no clue how since i never had a printer at home.

 

What have you created your artwork in?

If it's Photoshop then use the crop tool to select and crop an area, then Save As 'new file name'. This leaves your original untouched but leaves with a new A4 section of your job ready for proof.

You can even set the crop tool to A4 prior to selecting the crop if you have CS2/3/ or 4.

 

i haven't created anything, i'd like to print a photography but i don't have one yet, i was gonna look for it on the internet. that's why i asked which size of photography should be decent enough for this.

 

OK copyright issues aside. Perhaps your best bet would be to try istockphotos.com (or similar stock images sites), it's cheap and legal to acquire the use of a high resolution creative image for the purpose you mention. Everything else on the net tends to be fairly lo res.

 

i've briefly looked on istockphoto, and found one that is pretty nice, it's resolution is 3456 x 1734.
should that be enough for the print of the size i want, or i have to look for a larger one?

 

At 350ppi that'll give you a 5.5mb file when expanded.

Which gives 25cm x 12cm - on inkjet you could go up about twice that size...depending of the output software and inkjet device.

If that's the largest size they have then you have to resize in photoshop - this uses interpolation to increase the file dimensions. Since its going to be output on inkjet and the viewing distance is likely to be from several feet away you should be OK...but test a section first.