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Visualization
About built-in and 3rd party, classic and real-time rendering solutions, settings, workflows, etc.

Resolution and dpi explanation please.

Anonymous
Not applicable
Hi. I was wondering what does the meaning of dpi resolution next to image size (resolution). the dpi has to do with printing detail of an image no mater the resolution. So if you have a 600*400 with 75 dpi or 300 dpi image and you print it you with get the same result right?
4 REPLIES 4
TomWaltz
Participant
600x400 at 75 dpi would print out larger than 600x400 at 300 dpi.

600 / 75 = 8 inches across
600 / 300 = 2 inches across
Tom Waltz
Anonymous
Not applicable
TomWaltz wrote:
600x400 at 75 dpi would print out larger than 600x400 at 300 dpi.

600 / 75 = 8 inches across
600 / 300 = 2 inches across
Yes ok but this happens if you print from some image processing program or even directly from AC? I tried one 600*400 at 75dpi and one at 300 and when I opened the image from windows image viewer I didn't notice any difference.
The whole point of this question is to answer the question about large printing. So when we make a render to know if we need to set high dpi resolution or let it as it is and then use some image processing program to optimize the image.
Eduardo Rolon
Moderator
If i remember correctly the size in pixels is equal to the final size of the image multiplied by the the dpi.

If you need a 10"x10" image at 300dpi then you need a 3000dpi x 3000dpi.
Eduardo Rolón AIA NCARB
AC27 US/INT -> AC08

Macbook Pro M1 Max 64GB ram, OS X 10.XX latest
another Moderator

Dwight
Newcomer
syber wrote:
Hi. I was wondering what does the meaning of dpi resolution next to image size (resolution). the dpi has to do with printing detail of an image no mater the resolution. So if you have a 600*400 with 75 dpi or 300 dpi image and you print it you with get the same result right?
Yaggi daggi doogi!

This resolution thing is only important when viewing on paper since even small images fill normal display screens completely. When you evaluate something in Windows Image Viewer it is not telling you what you need to know about the information actually contained in the image.

When you have a 400x600 image at whatever size or resolution, most simple viewers will show you the image at that size on screen and disregard the excess information. Display screens have been increasing in resolution over the years. Old days was 72dpi but displays are increasing to the 100 and 200 dpi range. Such tiny dots!

A factor that contributes to the confusion is that few users know the optimum scale of their file that their printer needs. If you are printing full color to an offset device - like professionally printing a book, those guys need 300dpi to achieve the density of information their equipment can transfer to the printed page. Inkjet printers max out under 200.

So the math is simple as my colleagues have previously said.

Another factor when you are printing very large is that when viewers stand back to see the entire splendor of your artwork, lower resolution is okay. This does not apply to Professional Design Panels like we have in Vancouver where they look at things with a magnifying glass. For example, billboards like you would see in the street are made as coarse as 25 dpi.

Making large renderings has another, less understood problem. The resolution of your textures fails. In large renderings you often seen the surface detail of fabric or wood looking blurry while edges are razor sharp. The guy hasn't used a texture with enough pixels.
Dwight Atkinson
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