Changing DPI

[Willypill]

My dpi is at 96 right now, and when I go to my display settings and try to change it, it won't let me.  The menu is a different color (which means I can't click it).  It won't let me select another dpi setting.  I'm running a Geforce2 Ultra.  Is there any way I can change this?

[RayB]

Where are you seeing this option? I've never heard of screen resolution referred to as DPI. Only print document resolution.

[Willypill]

It's dots per inch.  Its in the display settings, in advanced.

[RayB]

It's dots per inch.

[wpcmame]

Oh I see it now. I've never touched that option to be honest. It's mostly to affect how text gets displayed if you find text too small.

The real use of the DPI setting is to ensure that text on the screen becomes the same size as on printout (when using 100% zoom level ofcourse).

If you want larger/smaller text, use a larger/smaller font.

(For some strange reason doesn't the DPI setting follow the screen resolution. If the monitor got 96DPI at 1280x960 it should ofcourse only have 48DPI at 640x480.)

[Harry Potter]

DPI is most commonly used to describe the pixel density in printing. Your screens 'DPI' remains constant. Maybe you mean dot pitch.

[wpcmame]

DPI is most commonly used to describe the pixel density in printing.

DPI has the same meaning on a monitor as on a printer. i.e. number of "dots" per inch. Technically the term should actually be PPI (pixels per inch) on a monitor but DPI is such well known term that it is used for monitors as well.

Your screens 'DPI' remains constant.

No, lets take an example. The physical horizontal size on a 17" monitor is approx 14". If you use a resolution of 1280x960 the DPI becomes 1280/14=91 but if you use a resolution of 640x480 the DPI becomes 640/14=46.

Windows uses DPI setting to ensure that fonts will have the same size on the screen as they have on paper.

Example: a 72 point(*) font is 1" high when printed. When rendering the same font on the screen it should be built up from 91 pixels (at 1280x960) and by 46 pixels at 640x480. (And will be built up  by 300 "pixels" on a 300DPI printer)

(*) Note that font size is expressed in "points" but these "points" have nothing to do with pixels. A point is a typographical term used long before computers with is the same as 1/72 inch.

It is true that LCD screens has a fixed DPI but that only applies if you don't scale the image to fit the screen, i.e. if 640x480 is displayed as a centered "window" with black borders.

Also have a look at the DPI settings in windows.
(Display properties/Settings/Advanced/General/DPI Settings/Custom Settings..)
You will see a ruler. The idea is that you lay a normal (physical) ruler on the screen and adjust the displayed ruler so that the inch markers on the screen matches the inch markers on the physical ruler.

Unfortunatly the DPI settings doesn't work properly in windows. E.g my laptop got a display of 1024x768 at 88 DPI but my desktop LCD got 1280x1024 at 96 DPI. Windows automaticly change the resolution when I connect the desktop LCD but the DPI setting is unaffected.

[Harry Potter]

Fair enough. I was generalising. Anyway, isn't it more common to refer to the physical resolution rather than terminology used mainly in the print industry?

If I change the res from 640 x 480 to 800 x 600, I don't say i went from 64dpi to 72 dpi. Because that brings up the question of monitor size also.

Anyway, i'm going back to Everything Else.