Explore related tutorials & articles
14
Replies
The above is entirely right. You do not need 300 ppi for large format printing. The bigger it is, the farther away it will be seen from, so the optical resolution stays the same. The eye wants to take in the whole image. You won't stick your nose into it.
Just for demonstration, look at a traditional monitor at 95-120 ppi. How close do you need to go before you see pixels? That's right, very close. For a wall-sized banner, as low as 15 - 20 ppi may be good enough.
300 ppi is for books and magazines to be seen at arm's length or less. Even so, there's nothing magical about the 300 number. It's not even a sharpness limit - it's a smoothness limit. With a standard halftone screen at 150 lines per inch, 300 pixels per inch is the theoretical upper limit beyond which no individual pixels can be detected. But it can still be eminently sharp at lower ppi.
All that said. 2250 x 1650 pixels is a small file to begin with. That sets limits to reproduction size under any circumstances. At 30", you will end at 75 ppi. While not disastrously low, it's still not very good.
Generally, all resampling disrupts the pixel structure and degrades the image. This is especially true for jpegs, which will never look good upsampled. In most normal circumstances, the image will look best as-is, without any upsampling. But sometimes you have to, to avoid visible pixels.
Putting that formula into a basic script:
/*
Print Resolution Calculator Viewing Distance - Feet.jsx
Formula from @davescm
v1.0 - 13th February 2024, Stephen Marsh
v1.1 - 14th February 2024, Added canvas size to the alert
https://community.adobe.com/t5/photoshop-ecosystem-discussions/photo-blow-up-question/td-p/14416674
https://community.adobe.com/t5/photoshop-ecosystem-discussions/quick-question-how-to-you-tackle-image-size-regarding-printing-projects-distance-dpi/m-p/13273751
NOTE: This script assumes that the correct print size is set in the Image Size window
*/
#target photoshop
if (app.documents.length) {
var theViewingDistance = prompt("Enter the viewing distance in feet:", "1");
if (theViewingDistance < 1) {
theViewingDistance = 1;
}
var feetToInch = (theViewingDistance * 12);
var theResult = Math.round(6878 / feetToInch);
alert("Poster Size Print Resolution Calculator: " + "\r" + "Viewing Distance : " + theViewingDistance + " Feet" + "\r" + "Calculated PPI Value: " + theResult + " PPI" + "\r" + "Document Resolution: " + Math.round(app.activeDocument.resolution) + " PPI" + "\r" + "Canvas Size: " + activeDocument.width.as('in') + " x " + activeDocument.height.as('in') + " Inches" + "\r\r" + "(Based on the viewing distance, the ability to resolve 60 line pairs per degree and current document print dimensions)");
} else {
alert("A document must be open!");
}
Or for those of us who use the metric system:
/*
Print Resolution Calculator Viewing Distance - Metres.jsx
Formula from @davescm
v1.0 - 13th February 2024, Stephen Marsh
v1.1 - 14th February 2024, Added canvas size to the alert
https://community.adobe.com/t5/photoshop-ecosystem-discussions/photo-blow-up-question/td-p/14416674
https://community.adobe.com/t5/photoshop-ecosystem-discussions/quick-question-how-to-you-tackle-image-size-regarding-printing-projects-distance-dpi/m-p/13273751
NOTE: This script assumes that the correct print size is set in the Image Size window
*/
#target photoshop
if (app.documents.length) {
var theViewingDistance = prompt("Enter the viewing distance in metres:", "1");
// Metres to feet
theViewingDistance = (theViewingDistance * 3.281);
if (theViewingDistance < 3.281) {
theViewingDistance = 3.281;
}
var feetToInch = (theViewingDistance * 12);
var theResult = Math.round(6878 / feetToInch);
alert("Poster Size Print Resolution Calculator: " + "\r" + "Viewing Distance : " + (theViewingDistance / 3.281) + " Metres" + "\r" + "Calculated PPI Value: " + theResult + " PPI" + "\r" + "Document Resolution: " + Math.round(app.activeDocument.resolution) + " PPI" + "\r" + "Canvas Size: " + (Math.round(activeDocument.width.as('cm') * 100) / 100 + ' x ' + Math.round(activeDocument.height.as('cm') * 100) / 100 + ' CM') + "\r\r" + "(Based on the viewing distance, the ability to resolve 60 line pairs per degree and current document print dimensions)");
} else {
alert("A document must be open!");
}
https://prepression.blogspot.com/2017/11/downloading-and-installing-adobe-scripts.html
AdChoices
