Sidwalkastronomy Loc: New Jersey Shore

I tried to go to far with a crop enlargement and printer company emailed me and said no go. MerridanPro did that and I use them all the time. That's good customer service.
I get 16x20 on metallic paper, outstanding

tgreenhaw

Many good answers here. 300 dpi is a good rule of thumb for those looking closely, however it depends upon the subject matter. If the resolution is too low, you will see obvious jagged edges on high contrast boundaries (e.g. text) and a loss of sharpness. More is better but you get to a point of diminishing returns if the image resolution is higher than that of the printing device. If the subject matter doesn't have high contrast zones 200 dpi might be plenty. Modern upscalers like Gigapixel AI can help a lot if you need a big print or need to crop. Very large prints viewed at a distance can be acceptable with as little as 100 dpi and billboards with as little as 12 dpi.

Longshadow Loc: Audubon, PA, United States

I just get prints the size I want them with whatever picture file I like.
No math, no calculating, no worries, just print.
(I will use the appropriate size crop mask though.)

cahale Loc: San Angelo, TX

I print up to 24" X 36" from digital images. Most are jpgs generated from a Sony a7Riii delivering a 12600 X 8600 box when upsized from the approximately 23" X 15" @ 350 resolution native size. I have no problem at all with clarity from as close as 1.5 feet away. I use an Epson P6000, which has a 24" limit on the short side. As always, the quality of the print depends, for the most part, on the quality of the file from which it is printed. Contrast, clarity, and sharpness/low noise level are the keys. Hope this helps.

MJPerini

Here is a simple trick to test. Edit, sharpen and size your image to 40x60, then take an 8x10 crop of an appropriate section and print it 8x10, Take a look
I believe Canon Print heads have 300 nozzles, Epson 360 That is why you will see 360 & 720 as options --720 for super resolution. You can also try "half resolution' settings of 150 or 180.
Depending on the image, you may find that it looks good at 180 ppi....or not. Viewing distance is also important.
There are several ways to 'up rez' the file in Photoshop or other dedicated software
High end printers are sometimes controlled by RIP software (Raster image processors) Like 'image print' by Colorbyte software
I use an epson 5000 and Image print and have had considerable success with Panos (The 5000 is an 11 ink 10 channel printer 17" wide by nearly any length --I have do as large as 17x60 with very good results.
You should discuss it with whoever is printing the image for you. Many services still use chromogenic processes, but many also use large inkjet like epson. File preparation is important, and some may offer uprezzing as a service. For maximum quality and largest gamut look for one that will use 16 bit TIFFS. Some only want JPEGS.
Depending on your image and file prep 40 x60 may well work. The better your file, the better the result.
Good luck.

Dennis833 Loc: Australia

300 PPI is an old standard that was recommended for printing in books ect. Back in the day graphic designers wanted room to move and crop images if needed. For large high quality photographic prints I usually set only the print dimensions and leave the resolution at maximin. I've also had a lot of images printed between 200-240 PPI and they have been great.

frankraney Loc: Clovis, Ca.

Yes you can print larger. Out depends on the viewing distance. Bill boards are printed at 1 dpi and they look good from a distance. Get close and picture diapers to garbage.

The 300 rule is to multiply the size of print by 300 per side to get a good print to be viewed about arms length.

Here is a site that explains thing in a way you might understand.

https://resources.printhandbook.com/pages/viewing-distance-dpi.php

imagemeister Loc: mid east Florida

300 PPI is way overkill ! Most 4-color magazines are printed with 133 line screens ......Fine Art America will accept files down to 135 PPI for printing and guarantee customers satisfaction. Personally, I like to see at least 165 PPI for MY printing on Fine Art America.

Longshadow Loc: Audubon, PA, United States

So glad I just send "large" (data) files and say "Here, print this.".

Paradise Pirate Loc: Cape Coral, FL

I take multiple pictures of subject split into panels that overlap a little then stitch them together in photoshop, pixels are no longer a problem.

Longshadow Loc: Audubon, PA, United States

300 PPI or 300 DPI?

burkphoto Loc: High Point, NC

Here we go again...

Pixels are numbers without dimension. The same file of pixels can be reproduced to any size output. You might not LIKE that output if you don't have enough pixels, but you can still reproduce them!

Dots are physical points on a flatbed scanner bed, or ink spots sprayed onto paper, or exposed points of light projected onto light-sensitive paper.

PPI refers to how many pixels of original image file data are spread over each inch of output. Original means un-interpolated, as in not artificially re-sized. PPI is usually used to determine whether an image will enlarge well to the desired print or display size.

dpi refers to how many "cells" exist in each inch of a scanner bed. A 300dpi scan divides the flatbed scanner glass into 300 square cells per linear inch, both horizontally and vertically, in a grid pattern. Typically, this is converted to a file by the scanner driver software containing the same number of pixels, assuming a 1:1 or 100% of original size file definition.

> If you tell the scanner driver, "Scan this 8x10" print at 300dpi at 100%," you get 2400x3000 pixels in the output file.

> If you tell the scanner driver, "Scan this 8x10" print at 300dpi at 200%," you get 4800x6000 pixels in the output file.

> If you tell the scanner driver, "Scan this 8x10" print at 600dpi at 100%," you get the same 4800x6000 pixels in the output file.

Once the image is digital/virtual/just pixels, "dpi" is meaningless until the image is printed on a SPECIFIC device. Some will argue that it is still meaningless. However, there are some graphic arts applications where dpi information in a file is used to size an image for page layout when it is imported onto/into a page layout.

[b]Besides scanner INPUT resolution, dpi also refers to printer OUTPUT resolution.[/] How many dots per inch does your printer use to reproduce the input pixels you send into its driver? You can send a file for reproduction at 8x10 inches at 300 PPI, but the printer driver converts that to some number of dots native to its design and technology. A desktop printer might spray 5760x2880 dots per inch to reproduce a 300 PPI photo. It might be able to print the same 300 PPI photo at 2880x1440 dots per inch in 1/4 the time, without too much reduction in image quality.

Except for Sigma Foveon-equipped cameras, digital cameras typically use an array of monochrome sensor elements (sensels or sub-pixel sensors), covered with color filters, to convert photons to electrons. The output signal from each sensel is digitized, then processed in camera or externally to convert sub-arrays of adjacent sensel data into discrete "bit maps" of pixel values. From that point forward, the file is just like a file from a scanner. Any "dpi" setting in the file is just arbitrary to many software applications.

If you hang around the graphic arts and photographic industries long enough, you will shake your head and laugh at the confusion over these concepts.

Dots are not pixels. Pixels are not dots. Pixels are digital. Dots are analog. It's bits vs. atoms, folks!

bonjac Loc: Santa Ynez, CA 93460

I read some years ago that if you multiply the diagonal of an image by 1.5, you will get the approximate viewing distance and I believe there are tables available that can guide you to the number of DPI for given viewing distances. I know this isn't a direct answer to your question but it may help to find the correct answer. As others have pointed out, DPI is largely a function of viewing distance. I've attached an example.

Good luck, Jack

Longshadow Loc: Audubon, PA, United States

What "Here we go again."???
I was simply asking him to confirm the units. That is all.......
Most printers reference 300 DPI.

burkphoto Loc: High Point, NC

I don't know of any printers (devices, not printing companies) that print at 300dpi. They may work best with 300PPI input because they convert that to a 300dpi grid, internally, then reproduce that grid with some native technology that generates dots.

I do know a number of printers (lithographic printing companies, and the agencies that use them) who ask for "300dpi files." In ALL cases, they will tell you that they mean 300dpi at intended reproduction size. The file itself is measured in pixel dimensions. The EXIF and TIFF headers in the file are then expected to specify enough information to calculate full, nominal dimensions. For instance:

DPI Height: 240
DPI Width: 240
Pixel Height: 3,072
Pixel Width: 4,608

This information indicates that the NOMINAL size of this file would be 19.2 by 12.8 inches. If you imported it into a layout without using a bounding box, it would flow onto the page at that size. Resizing it in inches in that application would adjust the DPI values. At 9 inches wide by 6 inches high, it would be 512PPI, as input to the printer driver or raster image processor (RIP) used to reproduce the image.

(NONE of the paragraph above applies in the photo industry.)

Years ago, standard practice would have been to RESIZE the image in Photoshop (etc.) before sending it to a printing company. This is because they don't want to clutter up their networks, storage drives, and processors with excess, un-needed information. Today, though, with ultra fast networks, SSD drives, and fast processors, few savvy printing industry folks care. They accept full size (but cropped) originals and let their RIPs do the resizing on the fly. Fewer resizes equals better reproduction quality.

By "Here we go again," I simply meant that this is the gagillionth time this subject has come up and been cluttered with confusion. I merely want folks to understand why the confusion over dpi vs PPI exists, and decode it for them.