Cannot understand how to make images bigger

[gordon77]

i have read a few threads on this topic and i cant quite grasp the technicality's of it all. i have a 400d and have taken and edited an image for a friend in photoshop cs, i would like to get it printed. the printing lab said they print at 300 dpi, thats dots per inch? im not even sure how big the image is that i want printed in the first place, how do i find out? im looking to resize to 10x15 inch. i need a very basic, easy to understand method of doing it, sometimes too much tech info confuses me lol so yeah, if someone could explain how to do it in photoshop cs thatd be awesome

 

[astrostu]

To change the image size in PhotoShop, go to the Image menu and select the "Image Size ..." option. In there, there is a "Pixel Dimensions" section and below that a "Document Size" section. In "Document Size" there are boxes for "Width," "Height," and "Resolution."

Type 300 into the Resolution box. Then type 15 into the Width and 10 should be automatically entered into the Height, assuming that your image is a 2:3::hight:width proportion.

However, your camera does not have this many pixels (13.5 Mpx, the 400D is a 10.2 Mpx camera). Consequently, you can set it to this, but you won't really increase the resolution of your image, it just "makes up" the missing information when it increases the size (generally uses a bicubic spline).

So you can do a 15x10" image, and you should be able to set the resolution to something lower such that you're not making up new pixels. If the printing lab has any technical knowledge, they shouldn't have any issues printing at less than 300 ppi (pixels per inch). But you want to not go below about 150 ppi, otherwise you will see artifacts.

The actual printer resolution should be more like a few thousand dpi (dots per inch). There was a discussion about this (dpi vs. ppi) awhile back: http://www.thephotoforum.com/forum/showthread.php?t=85554

 

[Mary]

Hey ya (",)

i read the last post and thats pretty much d easiest way, sometimes myself when i want a size say 20 x 16, i use the crop tool from the tool bar and just type in the size i want at the top,

 

[gordon77]

oh mate thats just what i needed to hear - thanks :hail: