Pixels/inch when cropping? help?

[Rich Brown Photography]

I have photoshop CS2 and am curious when i crop an image i set it to front image and i believe the default setting for when i crop is 72 pixels per inch. Should I change this or leave it be? Am i still getting the same resolution or losing it? I shoot with the canon eos 20d and just want to make sure im not royally screwing up my images when i crop them. The pixel dimensions i get for an uncropped image are 3504 wide by 2336 high when i shoot a landscape style shot. Please help me out. Thanks :)

[tim]

I think the default when you crop is not to specify a ppi value, which is what i'd recomend unless you have a very good reason to use a ppi value.

[Bodog]

Agree with Tim.

[Rich Brown Photography]

im not sure if i get it... when i open an image and hit the crop button it gives me in the tool bar my image width which is always 48.667 inch wide x 32.444 inch high then it lists the resolution as 72 pixels per inch. Are you saying that when i crop i should not change it to anything higher for more resolution? if so why not, what is the disadvantage?

What confuses me is in the tool bar on the top of the screen with the crop symbol, i can click on it and it gives me presets such as 4x6 at 300 ppi or 8x10 at 300ppi...is that what i should be using or stick with the 72 ppi? Thanks you guys and gals

[tim]

Agree with Tim.

Soon I will take over the world, muhahahahahaha! :D

[Rich Brown Photography]

tim...hmm...nice that you are going to take over the world but that isnt helping me much... but thanks anyways. maybe if you could clarify what you were saying before that would help me out.

[jfrancho]

Highlight the text in the Resolution box, hit Delete, and crop away without any resampling.

[subtle_spectre]

Crop tool, maybe?

[dbump]

Richard,
Have you checked Scottes' crop tutorial on this forum?
http://photography-on-the.net/forum/showthread.php?t=34567

For reference, that's under the 'sticky' thread, "Important Links" at the top of this forum, and again, under the Post Processing FAQ's in that post. Some great info in the other FAQ's there as well.

[tim]

Highlight the text in the Resolution box, hit Delete, and crop away without any resampling.

That's what I meant :) My evil plan started to slip out again, I must watch that ;)

[Rich Brown Photography]

so i should leave the picture dimensions alone such as 48 wide x 32 inch high alone and simply delete the resolution value (72ppi)? or should i clear all those settings? when i crop leaving the pic dimensions alone and hit front image to view the number of pixels ect...i end up with something like 50 ppi depending on how much i crop. Am i losing resolution or is that where is should be? thanks a lot for everyones help in advance

[Bodog]

Richard, the PPI is of really no consequence. It is the pixel dimensions that will determine the resolution quality. The more original pixels you have the better. PPI is only the RENDERED (printed) size at a given moment. It can be changed at anytime with no change to the image. You don't even have to bother with it really. Just tell your printer the size print you want and it will change the ppi on the fly. I'll repeat, it is the pixel dimensions that count. PPI is just an indication of a possible print size. As an example, if your image is 3000 X 1200 pixels, you can make a print 10' X 4" at 300 ppi, (divide dimensions by 300), a print 15" X 6" at 200 ppi(divide by 200), or a print 30" X 12 " at 100 PPI(divide by 100). Or any size in between. Large PPI = smaller, higher quality print, smaller ppi =larger, lower quality print. Your image does not change in either scenario; only the printed size. I'll also add, all image do not necessarily need to be printed at 300 ppi, anything above 250 will look good. For larger prints, you can even go below 200.

[Rich Brown Photography]

thanks for all the help. i think i get it now, no more fretting but one final question. Do most labs print at 300ppi at all print sizes or does it vary between large prints and small prints? thanks.... ive just been leaving my origional ppi at 72 and then cropping so i always have 72 ppi and according to this, since my lab changes ppi automatically depending on print size this should not matter...correct?

[tim]

The ppi doesn't matter, and some labs print at other resolutions. Elco, for example, recommends 254DPI and specifically says no higher.