What size required for A4 printing?

Hi all,
I want to send off to have some photos printed at A4 size to an online printer.
I did some editing.(Took ages!). Uploaded, and quite a few were rejected at the size as I had sent, as they said that the quality will not be good enough for A4.
What Pixels or mm do I have to save my files in Photoshop so that I will not have the files rejected?
My photos are taken with a 5DMK2 and 40D
Thanks for pointing me in the right direction
Ben

Ben Daniels wrote in post #10254495
Hi all,
I want to send off to have some photos printed at A4 size to an online printer.
I did some editing.(Took ages!). Uploaded, and quite a few were rejected at the size as I had sent, as they said that the quality will not be good enough for A4.
What Pixels or mm do I have to save my files in Photoshop so that I will not have the files rejected?
My photos are taken with a 5DMK2 and 40D
Thanks for pointing me in the right direction
Ben

You must have sent downscaled files because the 5D Mark II is more than capable at printing A4 natively.

Right click on the file you sent and click on properties. What is the resolution of the picture? It will be under the summary tab labeled as width and height.

Thanks for the reply.
I have looked at the properties -
All are .jpgs at 300dpi
Three are at 800 x 533
One at 1000 x 605
One at 1000 x 606
Is this the problem?
Thanks
Ben

What dpi were they saved at? I use an online printer ( pro-am imaging in Bradford ) and they require 402 dpi not the usual 300.
An A4( ish) image off my 40D is 4824 pixels*3216 pixels to give a 12*8 image printed at 402 dpi.
Off a 5D you should have more than enough pixels for A4

Ben Daniels wrote in post #10254607
Thanks for the reply.
I have looked at the properties -
All are .jpgs at 300dpi
Three are at 800 x 533
One at 1000 x 605
One at 1000 x 606
Is this the problem?
Thanks
Ben

Yes, it looks like whatever program you are using to edit is limiting the horizontal resolution to 1000 or 800 pixels

You have yourself a .6MP image there. The 5D MII is a 21MP camera. Check your export settings in whatever program you use to edit.

I am using a Trial of Photoshop CS5. It is me making the size too small I guess. D'oh!
If I know what the minimum is for a good A4 print, that is what I need to find out
Thanks

Ben Daniels wrote in post #10254607
Thanks for the reply.
I have looked at the properties -
All are .jpgs at 300dpi
Three are at 800 x 533
One at 1000 x 605
One at 1000 x 606
Is this the problem?
Thanks
Ben

1000pixels at 300dpi = 1000/300 = 3.3 inches = 8.5 cm much less than an A4 sheet on the long side.

An A4 sheet is ~30cm long, so at:
..300dpi you need ~3500 pixels on the long side
..200dpi, 2350 pixels
..150dpi ,1750 pixels

Many thanks. I will have to re do all the photos, but I will know for the future!
Hi to Melbourne . Time for bed?

Ben Daniels wrote in post #10254670
Many thanks. I will have to re do all the photos, but I will know for the future!
Hi to Melbourne . Time for bed?

10:10 PM ... not yet

Ben Daniels wrote in post #10254670
Many thanks. I will have to re do all the photos, but I will know for the future!
Hi to Melbourne . Time for bed?

Don't reduce the size of your images. Leave them their native resolution. More resolution never hurt anyone.

Even if I have cropped the photo?

Ben Daniels wrote in post #10256092
Even if I have cropped the photo?

The 5D2 has plenty enough pixels for a highest quality A3, twice the size of an A4. If you are cropping away more than half your pixels you either need to get closer or to get a longer lens.

What are you shooting that 280 mm. isn't long enough? How about 448 mm. (equivalent) on the 40D?

Ben Daniels wrote in post #10256092
Even if I have cropped the photo?

You should pretty much NEVER have to rescale an image. If you crop off pixels, call it a loss. You don't have to go and change the resolution afterwards.

Then you save with whatever you are left with, worst case scenario this should be at least half a quarter of your original resolution(cropping off half the image in each axis).

Printing FAQ

Thanks Tim for the info.
I still dont understand, but you could probably tell that by my haircut