Photoshop 6.0 changes resolution from 72 dpi to 96 dpi

2003-12-22 23:37:16

Photoshop 6.0 changes resolution from 72 dpi to 96 dpi when I use the save for web optimize feature to reduce file size. Is there any way to optimize an image in jpg format and keep 72 dpi? Thanks.

@Gary_Hummell

2003-12-23 01:35:39

There is no concern about dpi or ppi for web use because the image size is simply determined by dimensions in pixels. Inches have no relevance.

Gary

@Mac_McDougald

2003-12-23 07:41:14

Actually, SFW does not tag an image for ANY ppi.
You must be seeing the default setting for whatever is opening the file afterwards.
Of course, as Gary sez, ppi is meaningless for onscreen images anyway.

Mac

@JasonSmith

2003-12-23 20:16:03

Are you sure it's not showing PPC - Pixels Per Centimeter?

@reta_bohn

2003-12-23 22:10:47

Thanks for your replies. I am the Internet Manager at a Chevy Dealership. GM supplies a dealership website template and I upload the content. They told me to upload images that were 72 dpi because they load faster and won't frustrate viewers. I right click on the image, go to properties and then to summary and it displays dpi..not ppc or ppi. I want to reduce file size as much as possible and keep 72 dpi. I know I can use the save as feature but it does give me a preview like when I use the save for web optimize feature. Does it really make a diffence in loading time--72dpi v.s. 96 dpi? Or, is total file size more of a factor in quick loading? Thanks.

@dave_milbut

2003-12-23 22:24:02

dpi doesn't make a difference on the web. only pixel dimentions.

see:

<http://aikodude.tripod.com/difResTest.html>

top one is 72ppi (you're/they're confusing terms... dpi is for printing only). bottom one is 300ppi. same file size. same dimentions 800x600. exactly the same on the web. BUT printed, the bottom one is smaller because the 800x600 pixels are compressed down to 300 dots per inch where the 72ppi image will print at 72 dots per inch.

use save for web. it strips all ppi/dpi info. if you're seeing any in an application after saving, it's just that application supplying the empty field with it's own internal defaults.

@JasonSmith

2003-12-23 22:33:32

DPI - refers to analog dots. Printers print dots. The image wont have dots until it is printed/output.

PPI - refers to digital pixels. It is what any raster image is comprised of - the atom of the image if you will.

The DPI/PPI confusion is common - Adobe even makes that mistake with some of it's applications.

@reta_bohn

2003-12-23 23:01:37

Thanks guys! You answered my questions. I appreciate the help.

@dave_milbut

2003-12-23 23:43:12

¡de nada! ¡feliz navidad! :)