Photoshop Resolution PPI and DPI

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Understanding Photoshop Resolution PPI and DPI

For those of you who are uploading images to Picture Photos on Canvas or ZaZa Gallery to have them printed on canvas for 16 x 20 and 20 x 30 gallery wrapped canvas prints we like to see that your image has a minimum resolution of 300 at 4 x 6” inches. If you have any concerns or questions about the images that you are uploading to be printed so free to give us a call at any time at 707 – 364 – 0770.
We can work with images that have a lower resolution than this however before we
print these and all prints for that matter we make sure that the image quality meets a high standard and if we feel that it is not sharp in that you would otherwise not be happy with the final output in these cases it is our policy to contact our clients to talk about possible solutions before any prints are made. It is noteworthy that over 90% of the images that are sent to us by our customers have the image quality to make gallery wrapped canvas prints that they are satisfied with. The following information goes into a general explanation of image resolution as it pertains to printing.

You right-click on your image in Photoshop and you select image size then you see a dialog box that looks like this.

Click on Image to view larger

because it’s practical and because it is highly relative to the capacity of your image to look good when printed on media I have circled resolution in red. What is meant by resolution? Resolution in this instance might just as well have been replaced with PPI or pixels per inch. Really that is what this instance of resolution is referring to. That’s right, how many pixels there are in an inch. We can see the truthfulness of this statement if we look to the right where we see pixel/inch. A resolution of 300 pixels per inch is the standard for quality image output. If there are not enough pixels per inch in your image when you have a print made, your image will appear pixilated and you will be able to see individual pixels in your print. If you are going to be uploading your image to the web 72 PPI is all that is needed, as this is all that monitors can display.

The following is a comparison of a image with 300 resolution versus an image with a resolution of 72.If you have an image that has a resolution of 300 and is 3 inches wide by 3 inches high in pixel terms you would have an image that is 900 pixels wide by 900 pixels high. Your image would have a total of 810,000 pixels. If you have an image that was 3 inches wide by 3 inches high with a resolution of 72 pixels per inch. You would have an image to have a width of 216 pixels in height of 216 pixels. This image would have a total of 46,656 pixels.

The expression dpi refers to dots per inch. This expression relates strictly to print. DPI as it relates to PPI should be understood in this way. It often takes many more dots per inch and eight print to accurately reproduce the colors of pixels per inch. there is an excellent explanation of this on Wikipedia at the following link http://en.wikipedia.org/wiki/Dots_per_inch

Tags: dpi, photoshop, ppi, resolution, Resolution PPI and DPI

2 Comments to Photoshop Resolution PPI and DPI

1. 

   not only does that offer benefit to people uploading images for print, that was a very well written post that allows people to better understand how dpi effects the quality of the print
Nick Nieto on November 6th, 2008
2. 

   Fantastic explanation. People get so frustrated with the results of prints if they do not understand the basics of ppi and dpi.
Jena Ardell on November 7th, 2008