Help with dpi (dotty per inch - that's me this afternoon!!!!)


New Member
Here's a challenge...

When I look on Google about increasing dpi/ppi of an image, the advice seems to be just over type 72 (in this case) to 300 and there you have it - the resolution is increased. Surely this can't be so :icon_crying:

Firstly how do you alter the dpi of an image in Photoshop (I can only find an option to increase ppi).

Also, when I increase the ppi it enlarges the picture on the screen , ie when I want to increase the number of dots per inch, it seems to make the inch bigger on the screen. Surely the inch should look the same on the screen but the number of pixels in that inch should increase.

Am I being blonde? Should I just be looking forward to :icon_cheers: tomorrow to toast Will and Kate?

dpi is ppi (dots per inch vs pixels per inch) Image size is what you want in the Image menu.
Yes it appears bigger on the screen because you are looking at the pixels.
Increasing dpi from 72 to 300dpi does not give you a 300dpi image, the quality will not be the same.
Yup, in a nutshell, you can go from 72 to 300, but only with a loss in image quality (quite a lot), but you will never be able to increase the size of an image and retain quality unless said image is a vector and you're using vector based software such as illustrator.
You can increase the DPI in Photoshop BUT you will significantly reduce the size of your image.

Go to Image>Size and make sure Resample image is UNCHECKED then reduce the width or height number (lower than original) until the DPI gets to 300dpi.

It's not perfect but the best you can do without a larger, high res image
Basically you can only increase dpi and retain image quality by reducing the dimensions: for example, if you need to use an image for print where the optimum is 300dpi but your source image is, say, 150dpi, reduce the dimensions by 50% and you have a usable 300dpi image. That's really all you need to know.