Measuring your screen resolution

show more Measuring your screen resolution provides you with in-depth training on Photography. Taught by Deke McClelland as part of the Photoshop CS3 Sharpening Images show less
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Measuring your screen resolution

Over the course of next few exercises we are going to be discussing how to gauge the sharpness of an image on a computer monitor, which can be a tricky thing. For example, consider this. Imagine that you are going to be printing an image, which is not an uncommon scenario, so you are going to printing the image through an inkjet printer or a laser printer or sending it to a commercial print house for offset reproduction. Presumably, you are going to be printing the image at a high resolution, something like 267 or 300 or 360 pixels per inch, those just being a few common print resolutions.

All of them are heck of a lot higher than the resolution of your monitor. Now the reason that makes a difference is because you are going to be effectively shrinking your image when you print it and that means you are going to be reducing the thickness of your halos and so the halos are going to possibly disappear and the image is not going to look to sharp when you print it, at all. For example lets consider this guy right here, which is this by now familiar Sharp Shapes.pst files found inside the O1HowitWorks folder and I am currently looking at the Standard version of image.

Well compare to the Sharpened version of the image by selecting this layer comp, inside the Layer Comps palette. I am seeing the image at the 200% zoom ratio, the sharpness is altogether visible on screen. Too much sharpness going on. However, if I zoom out a little bit to the 100% zoom ratio, the image doesn't look quite so over sharpened. It's still over sharpened over on this screen; in the video it may look actually pretty darn right because our videos get resampled down a little bit. But for what it's worth, here's the difference between the sharpened version and the standard version of the image, so a more subtle change, not altogether subtle, but more subtle.

Now lets zoom out to the 50% zoom ratio right here and compare the standard version of the image to the sharpened version. Now on my screen I can see the difference. In the video possibly you'll see just the slightest difference on earth, and then if I zoom out to the 25% zoom ratio, this is the difference between Sharpened and Standard. I dare say in the video you are not going to see any difference whatsoever, and that's what happens, an image that looks sharp on the computer monitor at the 100% view size, does not end up looking sharp when it's shrunken down for print.

So what you have to do, before you can actually gauge the sharpness of the image, you need to be able to compare the resolution of your output to the resolution of your monitor and I am going to show you how to do that right now. And of course that depends on knowing what the resolution of your monitor is. So I want to show how to measure your screen resolution. Now contrary to the popular belief, it is not 72 pixel per inch. That's an absolute myth, as it turns to be based on very, very old information. Lets go ahead and switch to this slide right here. The name of this image if you care to open it up, it is available to you.

Its called Screen Resolution.tiff found inside that same O1HowitWorks folder. I am going to go and Shift+Tab away my palettes and notice that its telling us the screen resolution measures anywhere from a quarter to one-half the print resolution. Now this is assuming that you are printing somewhere between 267 - 360 pixels per inch. So here's the deal, the days of the 72 pixels per inch, PPI Screens are long gone, they are so long gone, people, they are dead, gone dead. That's back in the days of 1984, that's based on old Macintosh computers.

The original Macs, your Mac 128k, your Plus, your Classic, your SE, those guys, those little box computers that we kNow love and hate, they used to be 72 pixels per inch, but that was the end of that. They never were 72 pixels per inch again. However a lot of applications out there still presume that's a screen resolution iTunes. For example, if you are dragging and dropping an album cover from Photoshop into iTunes it has to be 72 pixels per inch in order to look right, and that is based on that old screen resolution.

So its a little bit of a convenience, but its a total myth. So its what I would call a convenient myth, is basically what it comes down to. But it has no bearing on today's monitors. Assuming default settings, modern monitors have resolutions of approximately 96 - 120 pixels per inch, now that is approximately. They can be lower res or higher res than that and certainly you can change the resolution of your monitor if you want to. But let us take an example here. This is a diagram of MacBook Pro Screen, a 17-inch MacBook Pro.

It has a native resolution of 1680X1050 pixels. So even though, its a 17-inch screen that's a diagonal measurement, that's how all monitor vendors and computer vendors, that's how they measure the screens. Presumably it's because the vendor would what are we supposed to measure, are we supposed to measure the width or the height. You kNow we spilt the difference when we pick the diagonal measurement. In fact that makes the monitor sound bigger because that's the biggest distance you can possibly measure on the screen. What I want you to do is take a measuring tape or ruler out and actually measure your screen. And in the case of this screen, it is 14.4 inches wide and it is 9 inches tall.

Now you want to measure the image-able area, that is the portion of the monitor that can actually display an image on screen. There is always a little bit of blackness at on the outer edges of monitor, don't measure that. So this has a resolution of 1680, which is the width in pixels, divided by the width of the screen, 14.4 inches. So 1680 pixels divided by 14.4 inches gets you 116.7 actually, but I am rounding it up to 117 pixels per inch. I want you to also to do the same measurement for your height.

So you would take 9 inches divided by 1050 pixels in this case and you get the exact same value 116.7. Now when you're measuring an LCD screen, you are probably going to get the same measurement in both directions. When you are measuring a CRT screen, which is a tube, a big monitor with a tube, then its very possible that your height and width measurements are going to be different. So the resolutions, that is to say, are going to be different for the height and width. If that's the case, I want you to select the smallest of the two resolutions and write it down.

So I actually want you to do that right now. I will tell you what to do with that information in a couple of exercises. Do the measurement, write the information down, then join me in the next exercise when we will look at the wacky world of zoom ratios inside Photoshop.

Measuring your screen resolution
Video duration: 6m 19s 10h 36m Intermediate


Measuring your screen resolution provides you with in-depth training on Photography. Taught by Deke McClelland as part of the Photoshop CS3 Sharpening Images

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