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
Or
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:
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 |