Another Technology Question

Heidi Kickhouse

Heidi Kickhouse

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Sorry to bother you guys with yet another question, but I'm old and technology stupid...

I am making a book with pictures that I've stolen from the Internet. How many KBs should a picture have to print out a good looking 4 x 5, or maybe even a 5 x 7?

Thanks if you know.


HK
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this is a toughy but i will try to explain

first, a pixel is a dot of light on a monitor or a dot of ink on piece of paper

standard number of pixels per square inch on a monitor is 72 ppi (aka 72 dpi) ppi=pixels per inch = dpi=dots per inch (you can see the individual dots (pixels) on your monitor. it is hard to see the individual dots of an image printed on a magazine, because the dots are smaller and densely packed together. this is called resolution), ie, density of the dots in an image

by convention, for print to a magazine or book, it is recommended, to have the image at 300 dpi, but i think 200 dpi would be the bare minimum before you start noticing jaggy edges in a image printed on paper

the problem is: the image(s) you have; is it formatted at 72 dpi or 300 dpi or somewhere in between? most images you get off the internet are set at 72 dpi, because thats all thats required, because browsing the internet is done on a computer monitor and a monitor can only show 72 dpi on the screen. keeping these images at the bare minimum resolution of 72 dpi keeps the images small in size (in terms of kb and mb) and makes the web page load faster. but you cannot use a 72 dpi image to print on paper. you will see jagged edges (just as you can see the pixels on your monitor). if your original digital image is large and it is set at 72 dpi , you can change it to 300 dpi with a photo editor application such as photoshop, but the photo will shrink because you are packing the dots together, ie, increasing the density of the digital image's dots. 72 dpi --> 300 dpi.

for calculating the resulting size when you convert 72 dpi to 300 dpi, take the original pixel size of your image (a point-and-shoot camera, may, eg, shoot like 1500x2100 pixels and cameras are usually set at 72 dpi (with the exception of high end digital nikon cameras that shoot with the arbitrary setup of 300 dpi). Set to 300 dpi, this would become a 5" x 7" printed photo. To calculate this:

1500 pixels ÷ 300 dpi = 5"

2100 pixels ÷ 300 dpi = 7"

of course you can change 300 to 200 dpi, if you are willing to go the bare minimum before seeing jaggys on paper.

if you are uploading to a site such as snapfish, shutterbug, or kodak easyshare that may automatically set your images to a printable resolution, ie, from 72 dpi to 200 to 300 dpi, you will not need to mess with changing resolution. but what you will need to know, which is what your question was originally *sigh*, is, what is the minimum amount of pixels i can deliver to shutterbug? you cannot tell what the resolution of the digital image is by looking at the size of it (kb or mb) because images are compressed in various ways which drastically vary the sizes.

so you have to look at the pixel dimensions of the image to know for sure. here are some calculations:

4" x 200 dpi = 800 pixels

6" x 200 dpi = 1200 pixels

5" x 200 dpi = 1000 pixels

7" x 200 dpi = 1400 pixles

(i'm using 200 dpi because it would be the minimally acceptable resolution before going to print)

so, to get a nicely printed image that is 4" x 5" on paper, you need a digital image of at least 800 x 1000 pixels, and for a nicely printed image of 5" x 7", you need at minimum of 1000 x 1400 pixels.

some websites that you upload to may reject your photo because the resolution is too low.
 
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This is so GREAT !!!

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Thanks so much! I totally get it, and I only had to read it over four or five times, which is not bad for me.. I am going to print out the walmart and microsoft sites too, but I think the explanation below may be what sticks in my teeny tiny brain.


I only have two quick follow-up questions (okay three, but the 3rd is about something else).

1. Is there a way to tell how many dpi's there are from the number of KBs? Like, is 100 KBs equal to so many dpis? (I just could not get subject-verb agreement to work in that sentence!)

2. If not, how can I see what the dpi number total is? It doesn't show up on Windows Explorer, and I checked all the column possibilities (details) for description, if that makes sense.


3. This last question is maybe is a little paranoid, but here goes:

If I link to a picture in a post here, through the C drive path on my computer, can others drive a reverse path back into my computer by following that link backwards?

Thanks so much to you both for this information; it is incredibly helpful!

...
 
1. Nope, can't tell how many dpi's there are based on number of kb's, because with automatic image compression, which is done in the background by the computer, an image that was 2 mb could have been compressed to 100 kb. But, in general, if an image is like 1 to 2 mb already, it is probably a good resolution for printing (unless its a TIFF file, but dont worry about this, I doubt you are working with TIFF, nevermind).

2. You have to use a photo or paint editor application to see the attributes of the digital image, unless there is something in windows that I'm not aware of (Spaz, you may know better). If you have Windows XP, right click on your image file, and scroll down to Open With..., and select Paint (which is the application known as Microsoft Paint). In the Paint application, click on Image, and select Attributes.... It will tell you dpi of this digital image and the number of pixels in width and height of your image. You cannot really change the attributes of the image with this application program, well at least not that I'm aware of.

If you bought a digital camera, they usually give you a photo editor application that should be able to change image attributes.

3. No, they can't go directly into your computer hard drive, there is no link to your computer. The image you place as an attachment on Spoofee are uploaded onto the Spoofee website host hard drives. But the acts of uploading, downloading, messaging, emailing, etc, there will be digital traces of the originator, ie, IP addresses are recorded in the background that can be traced if something urgent ever comes up that requires it to be traced. An IP address is the digital form of a street address but it takes the form of 4 numbers separated by dots, like, 70.128.192.210 Your homes connection to the internet will have an IP address. You can find out what your IP address is by going to www.ipchicken.com. On more thing, if you have any identifiers on your digital camera or the photo editor application, they are usually imprinted into the image. For example, if you registered your photo editor application, your name may show up in the attributes of the digital image you edited by the photo editor application.

4. What exactly are you doing with your photos?
 
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