Help needed! Minimum resolution for HQ A4 print

[Jerry van Dijk]

I'm about to enter a competition to get one of my photos published on the front page of a scientific journal. One of the criteria that the photo will be judged on is IQ. What would you consider as a minimum size for a photo that will be printed on about A4 size to still look good and sharp? The image that I have that best fits the theme of the competition is 2027x1351. A 100% crop of the image on my screen looks good, but could be a little sharper.
Any help is greatly appreciated!

[Diane Miller]

The issue isn't so much the starting size for an image but how well it will up-res and sharpen to the printed size. Most printers will do an excellent job with a file that is between 240-360 ppi. A4 is 8.3 x 11.7 inches (to translate to measurements I'm more comfortable with). At 240 ppi that would require a file of 1992 x 2808, and less if you want borders.

You're in that ballpark so your only issue would be sharpening. Test prints are the best way to determine how good you can make it.

But the dimensions you have are a different aspect ratio. That would be something to find out, what they want.

Best of luck with it -- sounds exciting!

[Jerry van Dijk]

Thanks Diane, it is quite exciting! My guess is that the pre printing work (sharpening, resizing, cropping) will be done by done by the journal itself, so my worry now is if the image in digital form is convincing them that it will hold up in that process. I may have to try some sample prints as you suggest. With the prints I've made (and that were made at a professional printing lab), I found that most of my images look better in print than I would have expected based on a 100% crop sample on my monitor. I think modern computer monitors are rather unforgiving in that they show every imperfection in good detail. It also helps that the prints I made so far were smaller than the size of a 100% crop that I'd use to check IQ.
I'll keep my fingers crossed anyway! I'll let you know when I was succesful in the competition.