Quick printing guide

Quick Printing guide

Updated on 25 July 2021

The purpose of this guide is three-fold:

Show you how to find the appropriate image resolution (in DPI/PPI, cf. below) for a minimum quality print
Show you how to calculate the maximum print size for a given image size in pixels (small, medium, high-resolution, etc)
Show you how to find the required image size in pixels for printing at a specific size (15x10cm or 6x4”, 18x13cm or 7x5”, etc)

If you are not interested in calculations or explanations, please refer to the Reference table at the end of this guide for a quick lookup.

Pixels: fundamental units of digital images

All digital images are measured in pixels, the smallest building block to create an image on screen, which stands for “picture element”.

The offered pixel dimensions are indicated in the Personal Use Download Pricing dialog before the currency in CHF, starting with the longest edge of the image. For example:

1024x681 pixels

1920x1278 pixels

2560x1703 pixels

4256x2832 pixels

What is DPI/PPI and what it means for printing

To prepare digital images for printing, we need to determine the resolution of an image which is measured in DPI/PPI.

The terms DPI (dots per inch ) and PPI (pixels per inch) are used interchangeably by error.

DPI stands for dots per inch and refers to the resolution of a printer. It describes the density of ink dots placed on a sheet of paper (or another photographic medium) by a printer to create a physical print. DPI has nothing to do with anything displayed digitally!

PPI refers to the number of image pixels from the digital file that will be used to create one inch on the printed medium. PPI is the more straightforward of the two terms. It describes just that: how many pixels an image contains per inch of distance (horizontally or vertically). PPI is also universal because it describes resolution in a way that doesn't vary from device to device.

Whenever you encounter the terms DPI/PPI together in the context of digital printing, they will refer to the number of image pixels that will be used to create one inch on the printed medium.

Generally, the higher the DPI/PPI, the higher resolution the image and the more detail will be in the final print.

If you want a more detailed explanation of the confusion around DPI / PPI, please refer to the Useful links at the bottom of the page.

Do I always need to print at 300 DPI/PPI?

Most printing labs will print images with the 300 DPI setting, but this is not a requirement.

For historical reasons, the setting of 300 DPI has been chosen to produce the best image resolution for hand-held prints, namely prints that are viewed at a distance of 60cm or less.

When assessing your DPI/PPI requirement, the main thing to take into account is the viewing distance.

Viewing distance affects your required resolution simply because if you stand further away from an image then the pixels get smaller. A billboard is rarely viewed closely so a resolution of 20-50 DPI will probably be fine. But the key point is to take into account how far away the viewer will be.

Here's a handy little chart to help you decide on a suitable resolution. It is based on someone with good eyesight.

Viewing Distance	Min Resolution
0.6m / 2ft	300 dpi
1m / 3.3ft	180 dpi
1.5m / 5ft	120 dpi
2m / 6.5ft	90 dpi
3m / 10ft	60 dpi
5m / 16ft	35 dpi
10m / 33ft	18 dpi
15m / 50ft	12 dpi
50m / 160ft	4 dpi
60m / 200ft	3 dpi
200m / 650ft	1 dpi

The recommended resolution range for best results on inkjet printers, depending on viewing distance and print sizes runs from 300 DPI to 140 DPI.

How do I calculate the maximum print size for a given pixel dimension (image size)?

Let’s say you purchased the medium image size with a pixel dimension of 1920x1278 pixels and your DPI setting is set at 300, based on your viewing distance (hand held print)

Apply the following calculation :

1920 pixels / 300 DPI x 2.54 cm (to convert to metric) = 16.25 cm maximum width

1278 pixels / 300 DPI x 2.54 cm (to convert to metric) = 10.82 cm maximum height

If you are allergic to maths, use either one of the following 3 online calculators:

Go to this page: https://prinfab.com/blog/viewing-distance-and-dpi/#image-sizing-calculator

In the Image Size Calculator, delete the default DPI to clear all values

1. Entre the pixel dimensions (image width = 1920 and image height = 1278)

2. Enter the viewing distance in cm, for example, 60 cm and press Enter

3. The calculator will display the maximum print size in cm and in inches

When you know exactly what DPI value you are expected to use for the print, you can use this pixel converter:

https://www.blitzresults.com/en/pixel/

Click on Pixels <--> Centimeters, enter the pixel values (width then height) and select 300 DPI. Click the Calculate button for results to obtain the maximum print size at 300 DPI.

Or this pixel calculator : https://www.pixelcalculator.com/index.php?lang=en

1. Click “Clear all” button in red to delete all values

2. In the center column, enter the length (width) and the height in pixels

3. Enter the required resolution, namely 300

4. Click the calculate button to obtain the maximum print size

The results indicate the maximum print size for your 300 DPI is 15 x 10 cm (6x4”).

If you wish to print at a slightly bigger size, let’s 18x13 cm (7x5”), you will need to decrease your DPI to 240.

1920 pixels / 240 DPI x 2.54 cm (to convert to metric) = 20.32 cm maximum width

1278 pixels / 240 DPI x 2.54 cm (to convert to metric) = 13.52 cm maximum width

Note that 240 DPI for small and medium-sized prints is quite acceptable.

How do I find the required pixel dimensions for a specific print size and DPI?

Use this pixel converter at https://www.blitzresults.com/en/pixel/ and choose the option:

Centimeters to Pixels

1. Enter the width of the print in cm (eg. 15)

2. Enter the height of the print in cm (10)

3. Specify the DPI setting, namely 300

4. Click the calculate button to find the required pixel dimensions for the image.

The required pixel dimensions are 1772x1181 pixels

Or, using this online pixel calculator: https://www.pixelcalculator.com/index.php?lang=en

1. Click “Clear all” button in red to delete all values

2. In the first column (left), enter the length in mm (width), namely 150mm

3. In the second row of first column, enter the heigh in mm , namely 100mm

4. Enter the desired DPI = 300

5. Click calculate

The required pixel dimensions are 1772x1181 pixels

You can also use this calculator “Desired Image Size Goal” if you want to work with inches:

https://www.scantips.com/calc.html

If you are avert to calculations and are unsure about the final viewing distance, please use this table as a target reference to help you choose the required DPI/PPI:

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Reference table

The table shows, for common print formats, the minimum recommended resolution in DPI/PPI and the minimum required sizes of the corresponding digital images in pixels:

Print Format			Common Usage	Minimum recommended	Image Size
Name	Size (width x height)	inches		DPI/PPI	pixels
A6 (ISO-216)	105 mm x 148 mm	4.13” x 5.83”	books, postcards	300	1487 x 2099
A5 (ISO-216)	148 mm x 210 mm	5.83” x 8.27”	books	300	1749 x 2481
A4 (ISO-216)	210 mm x 297 mm	8.27” x 11.70”	letters, magazines, catalogues	240	1985 x 2808
A3 (ISO-216)	297 mm x 420 mm	11.70” x 16.54”	posters, newspapers	200	2340 x 3308
A2 (ISO-216)	420 mm x 594 mm	16.54” x 23.40”	posters	180	2977 x 4212
A1 (ISO-216)	594 mm x 841 mm	23.40” x 33.11”	posters	160	3744 x 5298
A0 (ISO-216)	841 mm x 1189 mm	33.11” x 46.81”	posters	140	4635 x 6553
4R	102 mm x 152 mm	4” x 6”	photographs	300	1440 x 2160
5R	127 mm x 178 mm	5” x 7"	photographs	300	1500 x 2100
8R	203 mm x 254 mm	8” x 10"	photographs	240	1920 x 2400
	203 mm x 305 mm	8” x 12”	photographs	240	1920 x 2880
ANSI – A ( ≈ A4 ) Letter	216 mm x 279 mm	8½” x 11”	posters	240	2040 x 2640
Legal	216 mm x 356 mm	8½” x 14”		240	2040 x 3360
14R		11” x 14"	photographs	200	2200 x 2800
ANSI – B ( ≈ A3 ) Tabloid	279 mm x 432 mm	11” x 17”	posters	200	2200 x 3400
	305 mm x 457 mm	12 x 18”		200	2400 x 3600
	330 mm x 483 mm	13” x 19”		200	2600 x 3800
	406 mm x 508 mm	16” x 20"		180	2880 x 3600
	406 mm x 619 mm	16” x 24”		180	2880 x 4320
ANSI – C ( ≈ A2 )	432 mm x 559 mm	17” x 22”	posters	180	3060 x 3960
Broadsheet	457 mm x 610 mm	18” x 24”	posters	160	2880 x 3840
	508 mm x 610 mm	20” x 24"		140	2800 x 3360
	508 mm x 762 mm	20” x 30”		140	2800 x 4200
ANSI – D ( ≈ A1 )	559 mm x 864 mm	22” x 34”	posters	140	3080 x 4760
	610 mm x 914 mm	24” x 36”	posters	140	3360 x 5040
	689 mm x 991 mm	27” x 39”	posters	140	3780 x 5460
ANSI – E ( ≈ A0 )	864 mm x 1118 mm	34” x 44”	posters	140	4760 x 6160