help need with cropping

[markyb]

im not new to digital photography but never bothered much with editing.
question is .
when ive cropped pictures ive noticed that the pixel size is reduced by almost half depending on how much the photo is blown up.
what ive then been doing is going to resize and putting the original number of pixels back in. is this correct???
also was told to change all photos from 72dpi to 300 dpi so that print out would be better.

any advice for a novice will be welcome

[SamPhilly]

For me, I've never added back pixels. I crop frequently and so far have had no problems printing 4x6 photos.

[gstafleu]

what ive then been doing is going to resize and putting the original number of pixels back in. is this correct???


To state it simply: no. Cropping means throwing a bunch of pixels, and hence information away. Increasing the number of pixels afterwards does not put any lost information back into the picture, and is hence generally not useful. The only exception is if you have to make a large print, in which case you can upsample in a number of +10% steps (a trick I've read about, haven't tried it myself).


also was told to change all photos from 72dpi to 300 dpi so that print out would be better.

That only has effect if you then print the pic with a dpi-aware program, and don't resize it while printing. For inkjet printing, 200dpi is generally more than enough.