steve40 Loc: Asheville/Canton, NC, USA

Back when, I made several good 8x10 prints, from images out of a 1mp Fuji snappy. If you figured out the dpi, it was under 150, which is considered minimum.

The trick is most printers will re-optimise, any images sent to them to print. The out come, a contradiction of terms. :)

heltonjkv96 Loc: southwest Virginia

I ordered mine from shutterfly.com, Hope it turns out good it should be here tue. next week! Wish me luck..

robert-photos Loc: Chicago

I recently provided a chart and URL re: resolution required for print sizes in another thread on this Forum:

http://www.uglyhedgehog.com/t-18682-1.html

BOB Loc: Texas

all this dpi and pixels is just bunch jargon! to confuse people ...

flshutterbug Loc: FloriDUH

The myth still persists that you need high resolution for prints that are viewed from a "proper" distance. Unless you are pixel-peeping (which some photographers and gallery goers can't resist) the proper viewing distance for a print is 1 1/2 times the hypotenuse of the triangles that compose the print.

A 20 x 24 print creates a 32" hypotenuse (approx.) which means the viewing distance is about 48", or 4 feet. At that distance you couldn't see the difference between 150 ppi or 300 ppi.

bobrock111565 Loc: Leesburg, VA (near D.C.)

As someone else pointed out to you, the resolution you decide on depends greatly on the viewing distance. The further away you will be viewing the image, the lower the resolution you can still get away with.
But that said, if you want the optimal printing quality, you need to let us know the brand of printer you will be using. Optimally the ppi (pixels per inch) resolution of the image/print should be compatible with the printers' native resolution, so that no interpolation will occur. And this varies with manufacturer.
For example, my Epson (and all Epson's if I'm not mistaken) has a native resolution of 2880 x 1440 ppi. The resolution of your print should be evenly divided into these numbers. So for the Epson, it would be 180ppi, 240ppi, 360ppi, 720ppi, etc...I personally always use 360ppi for my prints. But HP for example uses 1200 x 2400ppi as its' native resolution, so in this case you should print at 300ppi. Get it?

If you don't base the image size on the native resolution of the printer, then the pixels will be interpolated (stretched or shrunken, so to speak) to match the printer. No always, but often this results in inferior prints.

But these are very fine points and most people will not notice a difference. But I'm a perfectionist and geeky about this stuff. So my advice, 360ppi if an Epson, 300ppi if another brand. But check the manual for the printers' native resolution.
Good luck.
Bob

nikonshooter Loc: Spartanburg, South Carolina

Right on with the math. You have to rez up the image in PS or use a RIP software program like IMAGE PRINT by Color Byte. You are back to 300 dpi.

So to answer your question....yes your image can be printed at that size and larger if processed correctly.

Send me the RAW File and I will rez the file for printing and return via Drop Box.....I imagine the file size to be 60mb.

George H Loc: Brooklyn, New York

Heltonjkv,
DPI should be no less than 300, that will allow you to blow up that big.

George

Jfwalkr Loc: Columbus, Indiana

I would shoot for 200 dpi or more. Using photo editing software, eg. Photoshop Elements, Photoshop, etc. Increase the size of your photo by 10% until you reach 18X24 at 200 dpi. Some say that 300 dpi is better, however, I had a professional tell me one time you needed at least 150 dpi. Increasing in 10% increments will give you better results than increasing the picture to your desired size all at once. When you are done with this process, you might want to sharpen it slightly too.

Jfwalkr Loc: Columbus, Indiana

Believe I indicated 18X24, I meant to say 20X24. You can't really go by the mb size of the picture, only the dpi at the desired print size.

Roger Hicks Loc: Aquitaine

Dear Mike,

The trouble is, most people aren't interested in a 'proper' distance, even if they accept your figures, which they may not: I have to confess I had never encountered this formula in my previous 45 years in photography. This ain't just 'pixel peeping': just about anyone will tend to look closer at something that interests them. It's all very well to say they shouldn't, but they will anyway.

Cheers,

R.

terrysmay

You should have something like 150 to 300 pixels per inch to make a print. If your camera doesn't produce enough pixels to reach this level of resolution, your image can be "upsized" using one of a number of interpolation algorithms to produce the appropriate number of pixels. The penalty is that the image will be somewhat softer because the new pixels are calculated by the interpolation algorithm and aren't in the original image. I use Qimage to print, and it does the interpolation for me after I specify the print size in inches. My first two cameras had resolutions of 2.5 megapixels and 2.0 megapixels and produced very good 13x19 enlargements, at least to my eye.

There is confusion as to the difference between pixels per inch and dots per inch (dpi). Each pixel is printed using a process called dithering that places very tiny dots of colored ink (often red, green, and blue, but sometimes other colors, depending on the printer) into a pattern that produces the correct color when viewed from an appropriate distance. The dot density can be very high. On my printer (an epson 1800) it is a choice between 720 dots per inch and 1440 dots per inch. Sometimes the dot density is different in the horizontal and vertical directions.

bobrock111565 Loc: Leesburg, VA (near D.C.)

No, it is NOT just a bunch of jargon intended to confuse people. For those of us that take our photography and print-making very seriously, it is very important. As "flshutterbug" pointed out, resolution becomes less important if you are merely displaying your images at a distance, such as a gallery. But if you are selling your images as high quality Giclee prints or to clients as family heirloom portraits, then you want the absolute optimal resolution and quality. I stand by that, as do most serious photographers. It's like telling a serious auto racer or collector that engine specs and aerodynamics of a car are just nonsensical jargon. All professions and hobbys offer varying levels of ability and technical sophistication. It's just jargon to you, but may be very important to others. (giclee

nikonshooter Loc: Spartanburg, South Carolina

I am not confused at all!

senad55verizon.net Loc: Milford, NJ

You guys are really confused.

DPI (dots per inch) is a printer resolution, and it's a matter for the person who's actually doing the printing. For good print quality, the dpi is somewhere north of 1000.

Deciding what kind of print resolution you need has nothing to do with dpi, it's all about ppi, pixels per inch.

Imagine making a print at 5 pixels per inch. 5 blocks of color in each inch, 0.2 inches per block side. Not a good photograph, very jaggy or "pixilated".

So, how many pixels in each inch do you need for a good photographic print? You can get by with a few less, but think of 200 ppi as a reasonable minimum. That means that you will need, for a 20 x 28 inch print: 20 x 200 x 28 x 200 = 22.4 total megapixels. Thats the same as 4000 x 5600 megapixels (another way to describe print resolution).

I usually try for 250 ppi, but you may be able to get by with 150. The latter would require a 12.6 megapixel image (3000 x 4200 pixels).

You can increase your image pixel count in Photoshop by resampling the image. Don't forget to pay attention to the choice of processing models at the bottom of the panel. To get there in PS, Image -> Image size. Caution: don't overdo it. Doubling the pixel count is usually much too much.

Cheers, and good luck.