Resolution Expert WANTED!!

Here is a very quick review of what we did two classes ago.
Resolution is the number of pixels in a screen. As we know, each pixel is made up of three colours. Red, green blue. Each one has 256 including 0.
If you put all the colours together, you get white.

Here are some new information we are learning about this class.
For finding the size of an image, you go to File, Image size. Once you click on that, a page will come up telling you the picture image. If you zoom up very closely, you can see the different pixel colours. Pixelation is when you can see all the pixels. By moving the picture back and forth, your not changing the resolution, you are just zooming in. 300 DPI (dots per inch) is the resolution we use for printing the pictures.
4 by 6 is the most common size for pictures.
72 DPI is the most common size we use for computers because you can't see 300DPI in a computer screen, so use 72 DPI for a computer screen.
Lest say you have 300DPI in your picture, and lets say you take half of the resolution away from the picture, so you only use 150DPI, you will half your pixels, meaning you will make your picture a quarter of the original. As much as you half the DPI, the resolution will be a quarter of the one before it. If you were to double your resolution on a picture, you will get four times the picture. The only time you would use 1200DPI is when you want to expand your picture once you have printed it.
If you want to print something, you would usually want a high resolution so that your picture will turn out better.
Rule: When you are working with an image, you always want to use the best quality and highest resolution. Once you want to put it onto the Internet, you can change the resolution.
But keep in mind that if you ever take information out of a picture, in other words make the resolution lower, you can never get the information back.
The pixels are the DPI. SO if you have a DPI of ten, it means that there are 10 pixels in one inch.
The last thing we are going to talk about is file format.
JPEG is a file format. It is that way you can save a file. JPEG takes some information out of a picture that is not needed. TIFF (tagged image file format)
PSD is loss less. No information is taken away. Always save your files as a PSD because it never takes information away from a picture. But if you save it as a JPEG, each time you open the file, not change anything, and save it again, it will automatically take some information away, even if you have not changed or touched anything of the picture.
But the disadvantage of a PSD picture is that they are big, therefore some people might not be able to open the picture.
I think I've learned enough today,
Bye. =]

-Peggy .