Making Larger Prints

I've been looking around trying to find the answer to this and it appears to either be;
There are too many variables or you get any number you care to think of.

If I wanted to print at A2 from a full frame sensor what realistically is the minimum file size at capture required for a good quality print - assuming exposure is as desired at capture and proper technique has been employed e.g. tripod, correct focus etc. with subsequent PP sharpening

I understand that conventional wisdom is using the print rule of thumb of 300dpi leads to about a 34MP sensor. However does this get reduced with viewing distance e.g.as with bill board size or is A2 too small for this to have much impact.

I also have a couple of further questions:

1. Does using interpolation to increase file size assist or is it better to stick with the native image on the basis that interpolation is making up pixels albeit in a calculated way?

2. What is the most effective way of testing what an A2 image will look like printed, without having the expense of actually getting the entire image printed

Any advice or input from those printing at A2 appreciated

I have successfully printed at A2 size from an 8 megapixel file. I have successfully printed much larger from a 24 megapixel file. As you mention, larger pictures have a greater viewing distance and pixel density is much less important.

taxboy said:

2. What is the most effective way of testing what an A2 image will look like printed, without having the expense of actually getting the entire image printed

Any advice or input from those printing at A2 appreciated

Click to expand...

to test, crop the picture to 1/4 - ie, crop out all but the top left quarter - and print that quarter at A4.

As long as it is properly sharp - as little as 10-12MP will do for A2, hung from regular viewing distances.

I don’t think I’ve ever printed A2 or larger at 300 DPI. I’ve currently got some 30x20” prints from a 36MP Nikon hanging in an exhibition and they look great, although a cropped one does look soft as although it looked fine on screen, I didn’t think to enlarge it - more fool me. To date, no one has commented.

For my last exhibition, I enlarged a 12MP micro 4/3 image using AI Gigapixel and had that printed at 30x20” and that looked great.

It comes down to who your audience is and whether you expect them to be ultra critical in their technical judgement (and be examining the print a nose length away from it with a loupe). If it’s for your wall at home, especially if it’s going to be hung over a piece of furniture, don’t sweat about it. If you’re hanging it in a gallery at a high profile exhibition (and I’m not talking about the local camera club annual exhibition in the library) or selling it, then maybe consider enlarging it - I’d recommend AI Gigapixel, but I believe some of the Photoshop tools are as good these days.

NOTHING to add here - the above have said it all

Dave

EDIT - not sure why I bothered then

If it looks good at A4 when held in the hands, chances are that it'll be fine at "normal" viewing distances whatever size you go up to.

With film the size you could print was limited by the size of the negative, the quality of the negative (detail/grain), and the viewing conditions (distance/requirement)...
Nothing has really changed; with digital it is the size of the negative (sensor), the quality of the image (detail/noise), and the viewing conditions. "Pixels"/PPI only matters if you enlarge it to the point where the square pixel shape starts to become visible, and at that point you need to interpolate/upscale.

Just enlarge it to an equivalent physical size on your monitor (i.e. 50% of the image occupies 300mm on your screen)... if it looks fine from the appropriate viewing distance then it will look fine printed (some additional sharpening may be required for ink/dye prints).

The 300dpi/ppi "requirement" is a carryover from digitizing film (scanning)...

Thanks to everyone. It's always good to get real world input to answer a question