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Trying To Work Out Screen Resolutions


awrieger

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I'm wondering how to do a picture so the fish appears actual size on other people's screens, but this 'pixels per inch' thing varies widely apparently. So this is a sort of unscientific survey because I'm having great difficulty understanding 'screen resolution' in relation to 'pixels per inch'.

The default web size for pictures in 'pixels per inch' is 72. I don't know why. Originally Apple Macs had 72ppi screens so if you did a picture at 72 pixels wide, it was literally 1 inch wide measured on the screen in real life. But now Mac screens are 100ppi, so a 72 pixel image is 72% on an inch. Or is it? Windows PCs are 96ppi or 120ppi, I think. So why this 72ppi 'standard' for the web?

So here are four squares. Each one is 1 inch high and 1 inch wide, but they've been saved at different pixels per inches, 72, 96, 100 and 120.

I'm asking you for a favour to participate in this survey and get your ruler out and measure what you see on your screen and let me know which one is closest to 1 inch in real life. See if it's actually possible to do an 'actual size' pic that everyone can see, or if everyone's screens are different so it's impossible! :)

1inch72.jpg

1inch96.jpg

1inch100.jpg

1inch120.jpg

NB. On my Mac I have two screens connected which are supposed to be the default Mac 100ppi each, but after a lot of experimenting it seems it's up to the actual manufacturer of the screen itself. Which are different, so 1 inch on one works out at 102.6ppi, while the other is 94.95ppi. On the same computer I can't even get the pictures the same size because the monitors are made by different companies!

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Thanks Lucy. After a bit of rough calculating, your screen seems to be about 86 pixels per inch.

I can see just from your reply alone that any hope of achieving an 'actual size' standard picture size for everyone is going to be very difficult if not impossible.

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the second one is closest to 1 inch for me. 1 1/16 inches.

the pic size all depends on your resolution and your screen size.

Most pc monitiors today come in 1024 by 768 pixels

but there are cheaper monitiors that are only 800 by 600 pixels and other more expensive ones that are 1600 by 1200 pixels.

also, on like a 15 inch 1024 by 768 screen, 1 inch may only be about 80 pixels, where on a 11 inch screen with the same resolution, may be about 110 pixels per inch.

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the second one is closest to 1 inch for me. 1 1/16 inches.

the pic size all depends on your resolution and your screen size.

Most pc monitiors today come in 1024 by 768 pixels

but there are cheaper monitiors that are only 800 by 600 pixels and other more expensive ones that are 1600 by 1200 pixels.

also, on like a 15 inch 1024 by 768 screen, 1 inch may only be about 80 pixels, where on a 11 inch screen with the same resolution, may be about 110 pixels per inch.

:bingo:

Fuzzy Peaches got it right on the nose. Though pixels per inch matter when it comes to printing an image, the display size is entirely dependent upon your screen resolution. I have a 21 inch monitor in the living room and it is set at 800x600 screen resolution, so even small images are HUGE.

Though your monitor alone does not determine your screen resolution, if you have a high end monitor and a low end video card, you will still have to use a low screen resolution, even though your monitor is capable of more.

My PC is capable of a screen resolution that is twice what my monitor is capable of... but my iBook has an integrated monitor, so they are equally matched.

Another thing to take into consideration is that some people are using wide screen resolutions on non wide screen monitors, so an image which is 100x100 pixels for example, would *not* appear square to them. They would have more pixels per screen inch width wise than they would height wise.

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Ok, this is coming from a guy who used to be an Internet Applications Project Manager, Web Developer, and Graphic Artist. I'm not usually a know-it-all. :)

Sorry to have to tell you this, but there is no standard worth using for pixels per inch on a screen. There's just too many different kinds of screens, and too many different screen resolutions.

The best thing to do is to look at the average screen resolution used by Internet users. You can get that number here:

http://www.w3schools.com/browsers/browsers_stats.asp

Currently most people on the Internet are running at screen resolutions of 1024x768 pixels or higher, and many are still using 800x600 pixels.

So the best thing to do is decide what percentage of an average user's screen do you want to fill with your picture. You'll have no clue what the actual dimension of the user's screen will be after all. Also, the mind adjusts perception of size to compensate for different resolutions and screen sizes. So trying to target an average pixel to inch ratio is pretty much a waste of time. :blink:

It's best, if correct perception of actual size is your objective, to put something in the picture that people can use as a reference for size. For example golf balls are sometimes used in photos of goldfish. Golf balls are the same size everywhere, where coins can be different sizes and rulers can be inches or metric.

So your objective is a good one, but your tactic is probably the wrong way to go.

BTW: For what it's worth (which is very little) on my 21 inch high resolution LCD flat panel running at 1600x1200 the 120px square is closest for me.

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AW- I expect daniels explanantion has it covered but for more variations from people heres's my screen analysis, only the last square measures an inch for me- the others are all quite a bit smaller. My screen is 14" :)

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Thanks everyone. Okay, I give up! lol

Daniel's obviously right. There doesn't seem to be any standard scale whatsoever between different screens. Perhaps this is an opportunity for some eneterprising web application developer (named Daniel ;) ) to write a browser plug-in called 'TrueScale'. Something that takes into account the individual user's screen resolution and so displays the picture accordingly at actual-size.

I can't believe in this day and age of high tech that the only way we can give an indication of scale to another person on their screen is by using a golf ball in the photo!

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I can't believe in this day and age of high tech that the only way we can give an indication of scale to another person on their screen is by using a golf ball in the photo!

I actually think this is a very good thing. Anything that gives the user control over their computer and web experience rather than the web site designer/programmer/artist or the like is a good thing in my opinion. And to borrow from Daniel, this is coming from a web designer/programmer who is constantly driven up the wall by having to design sites that function on out of date, non compliant browsers with obscenely low or high screen resolutions.

When users are allowed to set their own screen resolutions, ppi and other settings, they are able to take into account a million things that it is impossible for the original artist to even imagine.

If you have programs that force users to view something the way the artist intended it, you're taking away their choice to use their computer the way they are most comfortable with . . . and it *really* sucks to be someone who is forced to do something you don't want to do.

However, developing a program that allowed the user to display things life size or in the standard mode, would be *very* interesting. Giving them an additional choice as to how they wanted to interpret the world around them.

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I think it would work well as an optional plugin the user can choose to use or not. it would work really well with online e-stores where you could click the product's 'view actual size' button or something if you have the plugin installed (like flash or quicktime plugins). If the thing is bigger than your screen, you can scroll around.

I'd install and use it just to see how big the goldfish being sold online actually are for example. :)

Edit: PS: I still don't understand why the 'web standard' is 72 pixels per inch. While researching it, I was looking at a photography forum where one guy saves his images at 1 pixel per inch so if anyone tries to print them out, they're 300 feet wide in real life just to make it difficult for people as they have to resize it in photoshop. On screen of course it looks exactly the same size as a 72ppi picture.

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Edit: PS: I still don't understand why the 'web standard' is 72 pixels per inch. While researching it, I was looking at a photography forum where one guy saves his images at 1 pixel per inch so if anyone tries to print them out, they're 300 feet wide in real life just to make it difficult for people as they have to resize it in photoshop. On screen of course it looks exactly the same size as a 72ppi picture.

I like the way that guy's brain works.

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