72 DPI or 300 DPI - Which Is Better For Web And Print Both? [duplicate]

Question

Firstly, this may seem like a repetitive post. But please help me clear my doubt. It's based on my particular use case.

I am making a website where images will be available on web, but they can also be saved by users and printed. So I was wondering how much DPI should I choose.

I decided to google it out. But I am super confused right now, because I am getting completely different answers to this question.

Use Case:

• Adobe photoshop file (.psd)
• High resolution photograph
• 1000 px by 1000 px
• Saved as .jpg
• Upload to website as well (file size not an issue)
• Photo can be saved via website and printed

There are 2 different websites I found giving me different answers.

Website 1: 300 DPI

Print - 72 DPI < 300 DPI

Source: http://www.vsellis.com/understanding-dpi-resolution-and-print-vs-web-images/

"Print: 300dpi is standard, sometimes 150 is acceptable but never lower, you may go higher for some situations."

With examples of 300dpi and 72dpi.

Website 2: 72 DPI

Web - 72 DPI = 300 DPI Print - 72 DPI > 300 DPI

Source: https://daraskolnick.com/image-dpi-web/

This author shows an example of how 72 DPI and 300 DPI look when printed. And guess what, the 72 DPI image looks bigger. How???

Please search for: "Remember the three images I showed you above with different DPI values that look exactly the same on the web? Here’s what they’d look like printed:"

Sorry, but I don't understand what is going on here. Someone please care to explain?? Thanks in advance!

PS. Researching about this confused me even more. Haha. 😱😁

Answer 1

I will answer to clarify specific issues on the question.

I am going to be picky because I want you to analyze your process, so it becomes more clear to you.

• 1-Adobe photoshop file (.psd)
• 2-High resolution photograph
• 3-1000 px by 1000 px
• 4-Saved as .jpg
• 5-Upload to website as well (file size not an issue)
• 6-Photo can be saved via website and printed

• The moment you save an image as JPG (4) does not matter anymore how you worked your photo, Photoshop, PhotoPaint, Photoanything.

• 2 & 3 are somehow contradictory. A 1000x1000 image is one Megapixel, it is hardly the size to be considered as a wallpaper for old monitors; a simple wallpaper for an HD monitor is around 2 Mpx. Of course, depends on what was the camera producing that image, for example thermal cameras normally has lower resolution and in that case 1Mpx image could be a High res.

• Upload to the website as well... This is, are you uploading your 1Mpx image to the website? Therefore this 1Mpx image is going to be printed? You are going to print a low-resolution image.

"Print: 300dpi is standard, sometimes 150 is acceptable but never lower, you may go higher for some situations."

That statement is nonsense, because Print resolution, (expressed as ppi) depends on the viewing distance, original resolution, intended usage, etc. A billboard can be viewed at 100 mts, and can be printed for example at 1 ppi. A banner for a store could be fine at 25ppi, etc.

Website 2: 72 DPI

Well the link you consulted has this right... For a website the 72 ppi is TOTALLY IRRELEVANT. What matters there is that you have 1000 x 1000px period. So forget a 72 ppi version.

The question is:

Do you want to control what the physical size of the print on the anonymous user's home is going to be?

Then you care about the ppi (but in this case providing a JPG is not a good idea, you should use a PDF file)

Do you want the user to print a 1000px photo at 300ppi? Fine. The image will be 3 inches tall.

And guess what, the 72 DPI image looks bigger. How???

No and no. In your second reference, it clearly shows on the webpage 3 identical kitty photos.

The PPI info embedded on a jpg file is just a SMALL recommendation to the user's printer, that can be overrun, overwrite, forgotten into oblivion if the user turn on the fit to page checkbox for example.

If the user leaves some mysterious checkbox on his printer's window "use the ppi info on the photo" then, less ppi will be used every inch.

Kids eating candies

"Kids, how many candies each one will eat? I only have 1000 candies"

a) "We will eat 300 candies each one" So only 3 kids will eat candies. A small table will do.

b) "We will eat 100 candies each" So 10 kids can now eat candies and you need a bigger table for them to be.

3) "Kids will eat some amount of candies, depending on how many kids come to the party" Then the operation depends on how many kids actually you invited. If you invited 20, or 50 then the amount of candies will be different, and the size of the table to accommodate them will change.

Answer 2

It's really easy.

You print a certain number of Dots Per Inch of paper.

If you fit 300 dots of a 1000px photo into a single inch, the print will be 3.33 inches wide. (Let's assume here for simplicity dots=pixels, which isn't necessarily true)

If you print with 72 DPI, of course your 1000px image will spread out over 13.89 inches.

So DPI matter for the printer.

Monitors have a certain number of physical dots per inch, easily calculateable by measuring the width of your monitor and dividing the resolution (eg. 1920) by it. You can still view an image at any size you want, but "100% zoom" will be where 1px=1dot on screen.

The value stored in the image, on the other hand, is just a recommendation for the printing process, or a documentation of the scanning resolution. You are generally free to print at any other resolution you desire (and your hardware supports, of course).

So the question "which is better" doesn't even make any sense, since DPI is a property of the output device and process only.

Answer 3

What is being overlooked in many of the responses concerning 300dpi is that ink jet printer heads are designed to have optimal droplet size for a given application rate. Most use 300 ppi, while some use both 300 and 600ppi. This has nothing whatsoever to do with screen resolution and has everything to do with how the ink (whether dye, or pigment) behaves when applied to the print surface. Now if you try and print a 100 dpi image at 300PPI...you get a coarser picture.

My best advice is to contact both your printer mfr, AND especially the paper mfr. I personally do 80% of my prints on Red River Paper Co, stock. They have great support service and an excellent reference/learning library.