# Solved: Changing DPI



## Dingus (Apr 21, 2002)

Hi folks. Can anyone tell me how to change an images DPI using Paintshop Pro.


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## Dunko9 (Apr 21, 2003)

Dingus said:


> Hi folks. Can anyone tell me how to change an images DPI using Paintshop Pro.


what do you mean? your images DPI need change for Paintshop Pro? change to what?

Explain..


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## Dingus (Apr 21, 2002)

I need to change it to 300. At the moment it's too large


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## erick295 (Mar 27, 2005)

What are you trying to do here? If this doesn't involve printing then DPI is not what you're looking for.

I don't know about Paint Shop Pro, but in Photoshop it's in the Image Size dialog.


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## Noyb (May 25, 2005)

DPI or PPI is meaningless &#8230; basically stated.
What&#8217;s the overall size of the &#8220;Too Large&#8221; image, in Pixels .. And why do you think it's too large ??


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## Dingus (Apr 21, 2002)

I was looking to get some prints of a photo I had. The printer said he needed the image no more than 300 dpi.
The problem is solved now, as he said he would do it himself.
Thanks for helping tho.


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## Jones (Jul 28, 2005)

Noyb said:


> DPI or PPI is meaningless  basically stated.
> Whats the overall size of the Too Large image, in Pixels .. And why do you think it's too large ??


That's horribly wrong.

DPI has everything to do with image quality. The lower the resolution, the worse the quality of the image. If you're going to print, you need at least 300dpi to get a nice print out of it. If the images are only destined to be used on a computer, then 72dpi is usually the lowest you can go.


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## Noyb (May 25, 2005)

Really ???
Print a 600 dpi picture that is only 300 pixels wide at 12 inches wide and see what you get.


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## Dingus (Apr 21, 2002)

NoyB, hello again. Please check my post. My problem was with DPI (Dots per inch). Not pixels.
Perhaps I was too vague in my original post.


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## Jones (Jul 28, 2005)

Noyb said:


> Really ???
> Print a 600 dpi picture that is only 300 pixels wide at 12 inches wide and see what you get.


Totally missing the point. Of course that is going to turn out bad. It's no secret that enlarging any image made of pixels degrades the larger you go. It's a fact though that if you printed a 100dpi picture under the same conditions, the 600dpi pic would be much better than the 100dpi.

Anyone who has done any kind of real photo editing should know that there are three factors that affect the quality of the picture. Resolution, Dimensions, File type.

The point is DPI matters to image quality, and you said it didn't. All other things equal, a higher resolution image will be of better quality than a lower resolution image of the same dimensions.


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## erick295 (Mar 27, 2005)

Jones said:


> If the images are only destined to be used on a computer, then 72dpi is usually the lowest you can go.


You were right about everything up until this point. DPI doesn't matter unless the image is being printed. The myth (because that's what it is) that images on screen should be 72dpi started because Macs use 72dpi as a guide to display fonts. Windows uses 96dpi. This is just an estimate the OS uses to display an approximately correct font size on a monitor. Niether of these have anything to do with graphics. On a monitor, a pixel is a pixel is a pixel, and nothing else matters. It can be 1dpi or 1000dpi and it will look exactly the same (but print very differently).


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## Noyb (May 25, 2005)

Dingus said:


> NoyB, My problem was with DPI (Dots per inch). Not pixels.
> Perhaps I was too vague in my original post.


Not really ... Some image editors call it DPI ... others call it PPI.
Just don't do anything that changes the Total Image size in pixels ... such as resample.

The Total Image size in Pixels (or Dots) divided by the Physical size (usually in inches) ...
equals the DPI or PPI ... of the final display or print.
P/I = PPI or dots.

The computer only thinks in pixels.
The rest happens in the software that tries to communicate the Image to us Humans.

You should be able to tell the print routine what physical size you want.
Then the DPI will be determined from the total pixels.


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## thecoalman (Mar 6, 2006)

Jones said:


> All other things equal, a higher resolution image will be of better quality than a lower resolution image of the same dimensions.


That would only pertain to images where the dimensions are in *printed lengths*, it has nothing to do with pixel dimensions. Unless the printer requested images in a specific inch dimension with resolution of 300DPI they would be wrong too. The only time 300 DPI is relative is for scanned images where setting the DPI at 300 would make a difference. Besides that as Noyb stated it's irrelevant and in fact can lower the quality in the OP's case if done improperly. Here's some examples.

96DPI:









600DPI:









Photo Properties:









The 600DPI image is 2 Bytes more, probably due to the extra character in the resolution.  Otherwise pixel for pixel they are absolutely identical.

The DPI only scales the image, you can see how this works by opening Word or another application where the canvas size is represented in inches. If you import both images the *printed size* of the 600 DPI image will be about 1/6th the size of the 96DPI. The other place this can come into play is when setting the resolution/DPI you are scanning at. Basically DPI is a translation between the digital world which measures images in pixels and the physical world that measures in inches/cm.



Dingus said:


> hello again. Please check my post. My problem was with DPI (Dots per inch). Not pixels.
> Perhaps I was too vague in my original post.


I don't have Paintshop but there will be selection somewhere for changing *just the DPI*. You won't actually be changing anything except the default printing size and the printing company should just do this for you. BTW your question does pertain to pixels and in fact could greatly affect the image quality in your case since you have a image that is scaled higher. If for example you open up Paintshop and your image resize settings are in inches and you go from 600DPI to 300DPI and leave the size in inches the same you will be reducing the pixel size which is the most relevant size as far as quality goes. If this is a really large image in pixel size it won't matter much but if for example it was scanned from a wallet size image at 600DPI you could get a very decent printed image at twice the original size in inches. This will no longer be the case if you reduce it in pixels. Following me?????

What you should do is reduce the image to some ridiculously low pixel size then switch it to 300DPI and see what they tell you.   This is one of my pet peeves because without specifying a size in inches the 300DPI requirement is irrelevant.

Possible scenario: For example you scan a 2x3 image at 600DPI which is a 1200x1800 image. The printer requests a 300DPI. Not being aware of the affects of changing an images DPI and leaving the scale in inches the same you now have a 600x900 image but it's at 300DPI. You send it to the printer but the printed image is going to be at 4x6 so the printer scales it to that size.... That gives you the same size you started with in pixels but since it was scaled down in pixel size by you it's now a much lower quality image.... Do you hear me people in the printing industry?

There's a very simple and easy solution, they should request that *scanned *images to be printed at or below the original physical size be scanned at 300DPI. Scanned images to be be printed larger than the original physical size should be scanned at 600DPI. Digital images from cameras should just be sent as is. That would insure they get the best possible image to work with. They can set the DPI themselves, it's not as if it requires them to go out of there way to do it.


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