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Nov. 14th, 2007 08:20 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
which_chickI've gone over this before, somewhere, but it was a while ago and I've lost where I put it.
With any digital image, the image is defined by two things: the file size (measured in bytes, kilobytes, or megabytes) and the pixels (how many dots the picture is wide and tall). File Size is important for emailing things to people (bigger stuff takes more time, especially for folks still on dialup) and the pixels tell you how big you can make a 'real' print image without having it look craptastic. Right now, for our family, the pixels are important because of the Grandma Picture Frame Project. Because Dad HAS NOT yet emailed me with the specs on the Picture Frame, I don't have that information at hand for real world examples. I *think* but DO NOT KNOW FOR SURE that the Picture Frame is a 5x7 size with something like 700 px in the bigger direction. It'd be really great if Dad could get on the ball with this. Dad? You listening?
Anyway. Kb is important for emailing to people without broadband. Px is important for printing pictures and for Grandma's Digital Picture Frame.
Great! Where can I find this information (the kb and the px) about my images?
On your computer, you can find out the critical image information in Windows XP by opening the picture folder, highlighting the image thumbnail, and looking for the details at the bottom on the left-hand-side menu bar. You can also just mouse-over the picture (name, thumbnail, doesn't matter) and get the same information in a popup.
If you are having trouble with that method of determining image size, open the image file in your web browser. Right click the image and then, on the drop-down menu, click Properties. The file size and pixels should appear in a popup for you.
If you use Flickr, it TELLS you the px of the image size at the top, where it lists "square, thumbnail, small, medium..." Those are the "75 x 75" or whatever numbers right under the word descriptions.
Let's look at an example, here.
The above is a picture of apples. Now, right click on that image, get the dropdown, and left-click Properties.
The image is 1024 x 685. Because I wasn't all that certain, myself, about how big I could blow up images of a given size, I googled for some information about what image sizes (px) could be blown up for what size prints. Here is what I found...
"Most people accept 300 dots/pixels per inch as the "Gold Standard" for high quality. 250 is "recommended" by professional labs. 200 is quite acceptable. Flickr and other on-line services will give you a warning if you request a print lower than 150. Mpix will go down to 100 dpi for large prints."
"Gold Standard 300 dpi
Very good quality 250 dpi
Quite acceptable 200 dpi
Minimum 150 dpi
Really pushing it 125 dpi
Maximum possible 100 dpi
(source)
What? Confused? Let's do some math (Math Is Hard) on the apple picture.
The apple picture shown is 1024 x 685 pixels. Each pixel is, for the purposes of this discuss, a dot. Let's divide by 200 dpi (dots-per-inch), which is probably good enough for our purposes, and see what that does.
(scribble, scribble)
5.12" x 3.42" -- probably this would wind up OK as a 4 x 6 image. It wouldn't be pro photographer quality, but I am not a pro photographer. Probably I should not be making it much bigger than that, though.
The "real" apple picture, the original, is 3872 x 2592, which would print up to the 12 x 18 size.
Okay, so not everybody has a whoppingly huge and expensive camera like I do. How about other, more normal-people-sized pictures. How big can they be printed? Well, my older digital camera (about five years old, now) produced pictures that printed out very nicely on 4x6 paper at 2272 x 1704 pixels. They looked great.
Now, let us consider an image that is 320 x 240 px. Can this image be blown up to a 5x7 print? Well, yes, of course it *can*. Should it be? Well, a 5x7 print would require pixels of 1000 x 1400 and I happen to have handy here a tool that lets me resize an image to pixel specs of my own choosing. Via the magic of computers, I can show you what a 320 x 240 px picture would look like printed out at 5x7 print size, more or less. It'd look like this...
If you like that, go ahead and get the print done. If you don't like that, then save your money and don't go for the print.
My current Best Guess for pictures for the Grandma Picture Frame Project is that they should be at least 300 px in the big direction. That'll stretch ok to 700(ish) px for display purposes. Cameraphones are kind of pushing it, but most any $100.00 beginner-level point-n-shoot digital camera will be able to generate acceptable images for this frame.
With any digital image, the image is defined by two things: the file size (measured in bytes, kilobytes, or megabytes) and the pixels (how many dots the picture is wide and tall). File Size is important for emailing things to people (bigger stuff takes more time, especially for folks still on dialup) and the pixels tell you how big you can make a 'real' print image without having it look craptastic. Right now, for our family, the pixels are important because of the Grandma Picture Frame Project. Because Dad HAS NOT yet emailed me with the specs on the Picture Frame, I don't have that information at hand for real world examples. I *think* but DO NOT KNOW FOR SURE that the Picture Frame is a 5x7 size with something like 700 px in the bigger direction. It'd be really great if Dad could get on the ball with this. Dad? You listening?
Anyway. Kb is important for emailing to people without broadband. Px is important for printing pictures and for Grandma's Digital Picture Frame.
Great! Where can I find this information (the kb and the px) about my images?
On your computer, you can find out the critical image information in Windows XP by opening the picture folder, highlighting the image thumbnail, and looking for the details at the bottom on the left-hand-side menu bar. You can also just mouse-over the picture (name, thumbnail, doesn't matter) and get the same information in a popup.
If you are having trouble with that method of determining image size, open the image file in your web browser. Right click the image and then, on the drop-down menu, click Properties. The file size and pixels should appear in a popup for you.
If you use Flickr, it TELLS you the px of the image size at the top, where it lists "square, thumbnail, small, medium..." Those are the "75 x 75" or whatever numbers right under the word descriptions.
Let's look at an example, here.
The above is a picture of apples. Now, right click on that image, get the dropdown, and left-click Properties.
The image is 1024 x 685. Because I wasn't all that certain, myself, about how big I could blow up images of a given size, I googled for some information about what image sizes (px) could be blown up for what size prints. Here is what I found...
"Most people accept 300 dots/pixels per inch as the "Gold Standard" for high quality. 250 is "recommended" by professional labs. 200 is quite acceptable. Flickr and other on-line services will give you a warning if you request a print lower than 150. Mpix will go down to 100 dpi for large prints."
"Gold Standard 300 dpi
Very good quality 250 dpi
Quite acceptable 200 dpi
Minimum 150 dpi
Really pushing it 125 dpi
Maximum possible 100 dpi
(source)
What? Confused? Let's do some math (Math Is Hard) on the apple picture.
The apple picture shown is 1024 x 685 pixels. Each pixel is, for the purposes of this discuss, a dot. Let's divide by 200 dpi (dots-per-inch), which is probably good enough for our purposes, and see what that does.
(scribble, scribble)
5.12" x 3.42" -- probably this would wind up OK as a 4 x 6 image. It wouldn't be pro photographer quality, but I am not a pro photographer. Probably I should not be making it much bigger than that, though.
The "real" apple picture, the original, is 3872 x 2592, which would print up to the 12 x 18 size.
Okay, so not everybody has a whoppingly huge and expensive camera like I do. How about other, more normal-people-sized pictures. How big can they be printed? Well, my older digital camera (about five years old, now) produced pictures that printed out very nicely on 4x6 paper at 2272 x 1704 pixels. They looked great.
Now, let us consider an image that is 320 x 240 px. Can this image be blown up to a 5x7 print? Well, yes, of course it *can*. Should it be? Well, a 5x7 print would require pixels of 1000 x 1400 and I happen to have handy here a tool that lets me resize an image to pixel specs of my own choosing. Via the magic of computers, I can show you what a 320 x 240 px picture would look like printed out at 5x7 print size, more or less. It'd look like this...
If you like that, go ahead and get the print done. If you don't like that, then save your money and don't go for the print.
My current Best Guess for pictures for the Grandma Picture Frame Project is that they should be at least 300 px in the big direction. That'll stretch ok to 700(ish) px for display purposes. Cameraphones are kind of pushing it, but most any $100.00 beginner-level point-n-shoot digital camera will be able to generate acceptable images for this frame.
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Date: 2007-11-15 12:00 pm (UTC)Duh
Date: 2007-11-15 07:26 pm (UTC)