How much Mb for a large print?

How many Mb should a photo have as a minimum to make a high quality

print of 40 x 50 centimeters? How many pixels per cm2?

Please advise me on this as I am planning a photo exhibition. Thanks!

This is highly subjective. 360 ppi should be enough in a large print, so that would mean approximately 20000 pixels per cm^2. That's 40 megapixels for a print of 40x50 cm. Beyond that, it becomes difficult to see the differences on casual viewing especially because you need a pretty sharp medium format lens to get to that region.

 

You can print from 6 MP DSLR or 20 MP 35 mm scan but obviously the detail level will be less. But they might still look great depending on what your subject matter is.

I am not even sure if you need that much. I normaly send a 240 ppi at 40x40 to be print, and

the quality is stunning. As for the meg size, ask your printer at what PPI i need the final size

and check it in Photoshop you will have your answer.

240 ppi seems to be standard for large prints at labs but at least on high-end inkjets you can see differences when you go up in res. I agree that 240 ppi should be good, but it's not optimal if you have a really high-res camera.

MB, Mega Bytes, are not relevent to printing. Instead, pixels is what you care about. In this case, pixels per centimeter (ppc). Since 300 ppi will yield lots of detail, you get roughly 118 ppc for a nice print. Multiply this by your output size and you get 4720 x 5900 pixels. Albeit, you should do this based on the resolution of your output device. Some printers do 290 ppi, some do 400 ppi, injets move from ppi (pixels per inch) to dpi (dots per inch) and require you to use a much lower ppi than the dpi to allow enough dots to give you an ability of being able to print millions of colors for each pixel.

 

MB are not a useful measure here, it is pixels that matter.

 

Also, Mb, Mega bits, are a very different value than MB, Mega Bytes, as they differ in quanitity by 3 orders of magnitude (base 2). Hence 8 Mb are merely 1 MB.

 

enjoy,

 

Sean

Lab I sometimes use recommends 200 for large prints or even down to 180 with no really

observable effects on large format inkjets. For my own printing on an Epson 2200, I use 360

ppi setting.

Lambda prints are at 200 ppi. Just a benchmark for you.

Thanks for your comments! I apreciate it. Let me know if you need information on (photo-paradise) Ecuador; the place where I have been living for the last 15 years!.

 

chao,

 

Rik

Nope, at least Dialab prints on a Lambda at 400 ppi. But I don't like the results of that printer at all.

Since you're planning a photo exhibition, the bottom line is what will look good to you. Make your images as many megabytes as you are able to glean from the originals. It's better to have too much image information than too little, and downsizing for printing is not necessary.<p>

Do some test prints or have some test prints made at whatever different options are available to you, compare, put it on a wall, see what you feel. If you're happy with the result, go for that printing option.<p>

Hakon Soreide<br>

Bergen, Norway<br>

<a href="http://www.hakonsoreide.com">www.hakonsoreide.com</a>