How large files for magazine prints?

[Anders Östberg]

I wonder how large files are really needed for good quality prints? The pics I sent in to "reader's photos" they wanted "at least 1600x1200 and at least 300kb", which doesn't sound very large. They looked good in the paper though, at about A5 size at least. I've seen people offer scans up to 45 MB. When would this be necessary?

I'm asking because I had this idea of trying to upload some pictures to freelance image banks, and wonder how large they really have to be. At 1600x1200 and a few MBs it's relatively easy to produce great looking shots and I would guess they are big enough to be used in newspaper and magazine articles at least.

[MatsP]

I wonder how large files are really needed for good quality prints? The pics I sent in to "reader's photos" they wanted "at least 1600x1200 and at least 300kb", which doesn't sound very large. They looked good in the paper though, at about A5 size at least. I've seen people offer scans up to 45 MB. When would this be necessary?

I'm asking because I had this idea of trying to upload some pictures to freelance image banks, and wonder how large they really have to be. At 1600x1200 and a few MBs it's relatively easy to produce great looking shots and I would guess they are big enough to be used in newspaper and magazine articles at least.
It all depends on a large number of things. I used to work for a dinky-dodgy company called "Computer Pre-Press", and we'd sell equipment for the production of newspapers and magazines. In calculating the needed resolution, you'd use the "Lines per inch" (or lines per mm) that the product would be printed at. LPI is essentially the same as DPI, it's just a different background to the measurement (I beleive they used "lines" to separate "pixels" when reproducing photos in the original photoreprography/lithography).

So, anyways, good quality (glossy) magazines (i.e. your photgraphic ones) are printed at about 220 LPI, cheap magazines (Vänt i Häcken om den finns kvar) are about 150 LPI, and news papers around 100 LPI.

So now you know how many DPI you need. But generally, you want more than 1:1 DPI from the original, so ideally you want 1.5-2x DPI to the final printing resolution. So, in the end, you need about 350-450 DPI for high quality shots. 1600 x 1200 is sufficient for about A6 at this point. If you stretch it to 1:1, you will probably get about A5. For a two-page/centerfold spread:
16 x 13 inches, 220 LPI: 16 * 300 -> 4800, 13 * 300 -> 3900.
If we skimp on the "extra pixels": 16 * 220 -> 3500, 13 * 220 -> 2800.

So about the resolution of the EOS 1Ds MK2 for maximum resolution needed for a two-page spread. Or at least a 1D MK2 + some photoshop work!

I'd ask the image banks for advice on these things. I'm sure that they have guidelines...

--
Mats

[Anders Östberg]

Thanks Mats, great info!!

[gparr]

For the magazine I edit we can use about any quality jpeg if the image is going to be no more than a column (approx. 13 picas) wide. If it's going to be used on the cover or in a feature we require a print size of at least 5x7 inches, but prefer a print size in the area of 8x10 inches. Resolution has to be at least a 300 dpi jpeg in all cases. For features and covers, we prefer an 8x10 tif or eps. With a file of that size we can usually do whatever we want in terms of enlargement without image deterioration. I usually have people transfer those files to our ftp server because they typically are in the 20+ MB size range.
Gary

[Anders Östberg]

Thanks Gary!

[Queen Josephine]

Great info Gary and Matt!