Hey!
I want to print some images for a portfolio but some of the photographers do not have the originals. They need to be A4 so what is a suitable size res thingy in order to make this print look professional and hi quality? Thanks guys!

Frankie

http://www.photobox.ie/static/resolution_guide.html

According to photobox, for A4, you'll need about 1,600pixels+.  Photoshop or Lightroom will do it for you.

For printing, you're better off at 250 DPI (dots per inch or above). The more you go above this number, the better your print. The more you drop below it, the more evident things like pixelation, gradients etc appear.

A4 on it's longest side is 29.7cm - lets call it 30 cm, which is 12inches. At 250 DPI, that means the longest side on your shot should be at least 3000 pixels. Anything smaller than that and you're dropping the DPI.

People can cheat and simply upsize shots, but doing so incorrectly or badly will/can degrade your print. So if you're looking for high resolution images that are to be printed on A4, ideally they should be 3000 pixels on the longest side, or greater.

If Photobox is quoting 1600.. those prints will be a disgracefully low 133 DPI

Thanks guys that really helps but I am a little thick! I have an image that says this - Dimensions 3504 x 2336, size 1.56mb
Does this info tell me whether the image will be good quality so I can print it myself? It doesnt say anything about pixels!! LOL
If this info is enough to tell me whether I can print a good image from it then would one of you mind if I just emailed you about 8 dimensions and size of certain pictures and you can tell me if it is suitable or if I need to speak to the photographer! Sorry about this x

Smugmug says similar things to photobox...

http://www.smugmug.com/help/print-quality

"Recommended settings

Suppose your photo is 2000x3000 pixels and you expect your admirers to order anywhere from 6" prints to 40" prints. What should you do?

Our recommendation is to leave it alone. EZ Prints will upsample/downsample as needed and they can do it better than all but the most serious experts.

We can feel your worry and doubt:  "But...a 30-inch print is only 100 dots per inch..."  We routinely show the following print at 80 dpi, 24x30 inches to passionate and fussy photographers. Their only comment about quality is "stunning":"

It sounds like you'd get away with it.  But if you want to spend the money, there's several places around Dublin that will process it for you.

Divide each number by 300 to get the print size in inches (giving 11.7 x 7.8 inches).

P

brilliant thanks for all your help x

it does thanks ross. So as I am printing A4 with a white border as long as my images are about 3000x2400 or a bit less  I will be fine. So then....how do  you find out how many pixels are in an image?!?!?! LOL Shoot me now

Isn't that the whole purpose of this site?

:-)  P

If it was you would be taking me up on the offer :oP