DPI Dots Per Inch For Printing

The question how to choose a size for printing comes up regularly on sitepoint. For printing you should choose a document that has a resolution of 300 dpi (dots per inch). That will give a good result. For artworks you will need a higher resolution, but for that you would talk with the printer who will print for you.

For all documents that you want to print, you must multiply the inches x 300 in order to arrive at the right size. Take into consideration the margins that the printer requires for your layout. Margins are the edges of the paper where the printer can not print.

Most printers will need:
Top and Sides: 0.25 inches or 75 pixels margin
Bottom: 0.56 inches or 168 pixels margin

Here are the most common sheets of papers in use, their dimensions in inches and in pixels. For the layout on each of the different sizes of paper you must deduct the margin when you work your design.

US Letter: 8.50 inches x 11.00 inches or 2550 pixels x 3300 pixels
US Legal: 8.50 inches x 14.00 inches or 2550 pixels x 4200 pixels
A4: 8.26 inches x 11.69 inches or 2478 pixels x 3507 pixels
A5: 5.83 inches x 8.26 inches or 1749 pixels x 2478 pixels

If you want to print at a different dpi, then you must multiply the number of this dpi with the inches. For the printing of T-shirts as an example, you would prepare the image at 144 dpi. The ink will bleed on the fabric, finer printing is really not necessary.

To convert centimeters into inches, you have to multiply cm x 0.3937008.

Some really good info there.

Can we sticky this pleeaasseeeee

Ok i’m having real problems with a document. The document has to be 190mm x 130mm and have a resolution of 300dpi. What measurements and ppi do I need? I have done what I thought was right but when I look at the print size it’s not 190mm x 130mm… Please help! :confused:

• First, convert your mm into cm:
19 cm x 13 cm

• Convert those cm into inches:
19 cm x 0.3937008 = 7.4803152 in
13 cm x 0.3937008 = 5.1181104 in

• Convert those into pixels:
7.4803152 x 300 = 2244 px
5.1181104 x 300 = 1535 px

Your image size is: 2244 px x 1535 px

Make sure when you set the size not to forget to set the Resolution at 300.

If you work in Photoshop, you can just go into File > New. Set the document size to cm, put in your required size, also fill in Resolution: 300. Your Document should have the correct size for the image.

And do not forget to consider the margin that the printer needs, as explained in post #1 :slight_smile:

Thanks for this helpful thread Ulrike :tup: :smiley:

Just wanted to point out that 300 DPI (and higher) resolutions are not always best. For example, if you are printing on porous paper, such as newsprint that absorbs ink faster than a coated paper, 180-200 DPI is the maximum you would use.

Paper is a huge factor in choosing a resolution, and while generally speaking 300 DPI is a good rule of thumb, be aware that you also need to take into consideration what the image will be printed on.

Yes, that is very true, the more porous the paper, the lower the DPI should be, that is why I mentioned the T-shirt, very absorbent.

Your post is a good addition to this thread, since I probably should have included that. Thanks.

and, unless requested otherwise by your service beaureau, print house or broker, it’s not uncommon to supply greater dpi than is typical. They can scale it back as needed.

That is very true. But I would think that people who work in this field of printing will know about those requirements. Often in fine art printing even the scanners the print houses work with do not go above 300 DPi. Some go higher obviously :slight_smile:

Hello to all contributers to this thread.

I know the thread is about a month old, and I have just joined the forums, and should probably repost this information in a separate thread.

I would like to add to all of this good information and include Stochastic screening.

I have used this type of screening of dots for printing quite often with some very good results, especially for very fine work, like lace on wedding dresses etc. It avoids moire and clash of angles if the nature of the printed image has fine patterns in it. Digital photographic images can sometimes also be riddled with little patterns that need to be blurred if you are setting up a high quality print.

Before you decide to go to Stochastic or FM screening, speak to your printer to get the specs required for their particular plate setter, or your film house for their specs on the film screening. Well worth it for that extra high quality result.

Good work.

@Kai Gusto – thank you! Your knowledge is a great addition to this thread. It is a tut, and they stay open for comments for a long time.

Ulrike

To add to that information I have a recent experience to share.

We did a photo shoot for a flyscreen doors and window company. The fly screens of the products were a major problem with a Canon D60 8mp. We solved the problem. REMOVE THE SCREENS in the doors and the windows samples before the photo shoot.

We ended up masking the products and added a transparent grey where the screens used to be. Printed beautifully at 300 dpi on glossy stock.

Life long learning, yeah.

That was an excellent solution. Thanks for sharing.

Sometimes you would like to calculate how many MBs a file will have.

To calculate the Image Size in MB (megabytes),
multiply the width (in inches) x the height (in inches) x the resolution (dpi) squared.
Then divide the total by 344,000.

Example of a file that is 8 1/2 x 11 inches, 300 dpi.:

8 1/2 x 11 x 300 x 300 / 344,000 = 24.46 MB

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NOOOw I know

cool! very useful info here guys! thanks! :slight_smile:

I was searching for DPI info and found this. Awesome info Datura.