What's the point in worrying about dots?
20 Dec 2017
20 Dec 2017
Dots per inch isn't a measure of the resolution of a digital image, so why do people treat it as though it is, writing it into job specifications for digital images?
You can set the dpi resolution of a photograph using most photo-editing software, for example, Photoshop but also GIMP and others, but doing this has no effect on the digital image. The pixel dimensions remain the same, the image itself remains unchanged. The only place this has an effect is when you print it out, although even then, usually when you go to print a photo you have the option to set the print size yourself, overriding the dpi that you set. Basically, the dpi you can set in photo-editing software is only a suggestion that doesn't come into effect until you go to print.
If you're using the image in some kind of page layout software such as Illustrator or InDesign then most likely, when you import the image, it will be sized on the page according to the dpi that was set. However again, the dpi is only about the image's size on the page, and until you print it out you can still change that, making use of the full resolution of the original image. If you then start to resize the image to fit your layout then you're overriding that dpi and usually there will be a way to see what the actual dpi is.
In short, unless you're trying to streamline your workflow by having all your images automatically sized for a certain dpi, there is no benefit to setting the dpi within your photo-editing software. The dpi settings wherever you see them are just 'soft' settings that change the way something prints, not the underlying data.
The relevance of all this is that dpi is of course still important when you come to print the photograph, but I do sometimes get photographs sent back to me asking if I can change the dpi and it really isn't necessary for me to open the photo up in Photoshop, change the dpi, save it again and then send it back, and if you're working on a jpeg then all that will achieve is degrading the quality of the photograph because each time you re-save it you're also degrading it.
Articles about photography, tips and tricks, insights into the world of commercial photography and the marketing industry from a photographer's perspective, and the occasional humorous rant. Brought to you by Will McAllister, a commercial photographer based in God's own county of Cumbria.
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