Say No to 72 dpi

[Ken Cox]

SEE

Say No to 72 dpi

http://www.scantips.com/no72dpi.html

http://www.ibateman.co.uk/wcc/av-group/av-resolution.htm

AND ANOTHER FORUM MEMBER

http://gdesroches.free.fr/formation/fnumerbase_en.htm

http://gdesroches.free.fr/formation/fnumerbase_en.htm#72

http://www.gdesroches.com/panoramik.htm

ken

[Lin Evans]

SEE

Say No to 72 dpi

http://www.scantips.com/no72dpi.html

http://www.wantage.freeserve.co.uk/frameset-avgroup.htm

Audio Visual Group

What is Audio Visual? RIGHT SIDE COLUMN The Myth of 72 DPI

AND ANOTHER FORUM MEMBER

http://gdesroches.free.fr/formation/fnumerbase_en.htm

http://gdesroches.free.fr/formation/fnumerbase_en.htm#72

http://www.gdesroches.com/panoramik.htm

ken

Much of the confusion comes about because when Photoshop was invented, the MacIntosh B&W displays and Mac's ruled desktop publishing. Adobe adapted the then pixel pitch of 72 pixels per inch used on the old monitors and made the error of calling it 72dpi which is a printer's term. Commonly newer color monitors display something in the order of 96 pixels per inch and above and the confusion has been rampant ever since. They also make the mistake of referring to it as "resolution" which is another misnomer.

When we deal with scanning, we want an image which has a decent pixel count. The pixel count is determined by the scanning resolution and typically, for screen display we want something equal or larger than our highest screen resolution so we can resample to suit whichever display we use. For printing we want to match the input resolution of the printer engine which for commercial purposes is usually 300dpi, but we want 300 at the SIZE we intend to print unless we want interpolation.

But since the majority of users today have digital capture devices, we start with whatever the capture provides in terms of pixel count. Many, if not all the older digital cameras simply adopted 72 (dpi) as a standard EXIF tag. Canon decided to make it 180 (dpi) and does so on many of their newer cameras.

As the article points out - (but keep in mind that this stems from a scanning perspective) the dpi number simply describes the size of a print at a given pixel density. If you make the print smaller, then the same number of pixels are placed in a smaller geographical area making the (dpi) print density greater. If you print larger then those same pixels are spread out.

The display on any monitor has a pre-set density into which these files must be displayed to they are either upsampled or downsampled if you elect to fill the screen (assuming aspect ratio compatibility). Other wise you must use a program like Photoshop to pan about to see the entire image.

A projector doesn't give a hoot about pixel density information in the EXIF file. It doesn't matter one iota whether the density is 72 dpi or 1000 dpi to the projector, it only cares how many pixels make up the matrix. You get the best results when the projector doesn't need to resample so do it in Photoshop, etc., to match the projector output before feeding it the file and everything will be a good as it can be assuming compatibility with colorspace, etc.

Best regards,

Lin

[Ken Cox]

SEE

http://www.picturestoexe.com/forums/index....t=0entry31792

http://www.picturestoexe.com/forums/index....t=0entry31804

http://www.ekdahl.org/test_dpi/test2dpi.htm

KEN

[Ronniebootwest]

This post seems to be linked to my previous post called 'What width and height is best' or am I seeing things

Ron

[alrobin]

This topic is like "quack-grass" in your lawn - you can't kill it! (see also post #1 in this thread.

[Ken Cox]

WELL MR "BRIAN" thought it would be a good idea to have one spot for 72 dpi for newbies so i created one

then Brian started another thread,

http://www.picturestoexe.com/forums/index.php?showtopic=4762

so i am just trying to keep them all in one place

and

keep things half a__ed organized but i seem to be losing

if you want this thread removed it shall be done -- just say the word

if people would practice "RAT's" we would minimize these problems

what you ask is "RAT's" ?

read all threads not only in certain sections but in all sections

ken

[ronwil]

I agree with you Ken to read all threads not only in certain sections but in all sections. However some threads are rather verbose and when they are preceded by a full quote of an equally verbose earlier thread it becomes rather taxing. I wish members would give due consideration to usung the ADD REPLY button rather than the "REPLY one before making their responses. The use of the latter when making an immediate reply is particularly irritating when you have just read this previous message and you get it all quoted at you again and ending with "Thanks X".

The long threads which I like are those which are clearly laid out and easy to follow.

Ron [uK]