there could be no resolution attached and your machine defaults to 300 (or 299.99) and his defaults to 72. ppi not dpi.
interesting…but wouldn’t a png by default have a resolution?
It probably has something to do with the way PS is reading the header information in the files. The file may not have a value stored for the ppi of the image. So PS6 defaults to one size and PSCS3 to another. That’s just a guess.
but wouldn’t a png by default have a resolution?
nope. for example if you use save for web that strips out resolution info which is after all, just meta-data. what’s important are the pixel dimensions. resolution doesn’t become important until you got to either 1) use vector objects, or 2) print it.
gotcha. However, we are unable to process them because of company standards regarding images. (that metadata counts for something)
Guess I will just have to resave them "with" resolution. Thanks!!!
Guess I will just have to resave them "with" resolution. Thanks!!!
that’s the ticket.
OK, I have the same problem, I create files in 300 dpi, and for example 12×12 inches. I save as png, and when I open them there are at 72 dpi and something like 50 inches. But everything is OK with jpeg images.
My preferences are 300 dpi for print resolution, image 150 lines/inches… So where could I change something more to open my png file into 300 dpi ??? I feel lost now….
if you used save 4 web to save the png’s that strips out any resolution info you set. use "file> save" or "file> save as" if you want to retain resolution info in the image.
if you used save 4 web to save the png’s that strips out any resolution info you set.
To clarify: there is no "resolution" on the web, so there is on need for resolution data when saving for web. Resolution only applies to printing. On the web, only the pixel dimensions matter, and they do not change when resolution changes (normally).
I always save by file> Save as and my images are not for the web. I need them in 300 dpi. I don’t know why the problem appear since several days only and not in my french version of Photoshop, only in the english one.
I try to see what is the difference in Preferences between the both, but nothing "jump in my viw", nothing special….
I bacome "green" with this problem as I need my english version for some actions I usually use (I am lazy to transate them)…
Olease help me !! I will crack myself !!!
OOOOhh !! Dave, you are my hero !!!
It works, I feel very ….."redevable" !!!
I always feel like something weird that I can’t understand with this starnge thing, but, do I have to search why it change ?? … wasting of time ?? may be I will search.. But now, I know how correct this strange comportement and I thank thank you so much !!!
I will share this "tip" with my friends I warn to know if some of them know what happen… Know I will be their HERO too !!! LOL !!
Thanks so much !! <where could I send you the Champagne ?? (LOL!!)
lol! you’re welcome caro. 🙂
Here’s a problem that I haven’t been able to find an answer to…
I converted 180ppi images to 300ppi using a program called ImageMagick.
When I open the image up on my machine the image size states that it is 7.454ppi, which is not what I want it to be. I want 300ppi.
However, when I open up that same exact image on a co-workers machine the image size is 300ppi like I wanted.
Both machines are running CS3.
Any suggestions or feedback greatly appreciated as this has been driving me crazy for weeks.
Thanks,
Pete
Dave:
Do you know that PS strips the resolution (ppi) bit (or two) from the JFIF headers when SFW? Given that the web preset can be changed to any resolution in PS, but re-imported SFW JPGs all come in at 72, I deduce that it does not, and leaves 72 ppi as the JFIF resolution bit. But that’s faulty logic at best. Any documentation?
J
The ppi metadata setting in an image file means nothing except what a user may want to print the file at. It has no effect on the image data at all. At the time of printing this setting can be over ridden with no problem, so it is merely a guide or suggestion, not a given!!
A camera may put a default ppi in the image file to start with, or it may not. Some editing programs read the ppi setting in the image file, and others do not. Some programs will default to a ppi setting if the image file has none in it.
Once you begin to edit your image you can place any ppi setting you want in the image file, but again it has no effect on the image data. The image data is h x w in pixels, and the ppi is only a suggested printer setting, but can be over ridden when you go to print.
So forget your ppi and concentrate on the actual h x w pixels in the image….
Ed
The ppi metadata setting in an image file means nothing except what a user may want to print the file at.
All files I work on are for the web AND for print. In this day and age I’m not sure how anyone could feel otherwise about their work. But hey, if people want to strip those bits to save space or pay homage to something they learned at school, they can be my guest.
I’m interested in the JFIF headers (not the EXIF metadata) to settle an old score. If you’d like to partake I’ll abide.
so it is merely a guide or suggestion, not a given
Kind of like those yellow lines on the road. Or even sRGB.
I can’t find any resolution (ppi) values using hex editors in images created with SFW. I can find that data in images created through save as, and the values appear (IIRC) in the JFIF "subset" area of the file. Why PS doesn’t assign your web preset to these images (instead defaulting to 72) I don’t understand.
(instead defaulting to 72)
it doesn’t default to 72 when saving. it strips all resolution data out when saving (for web). it defaults to 72 when opening a file where it finds no resolution data.
Thanks Dave.
I was confusing in post 18; I did mean "assign" only when opening. Why is this value (72 ppi) preferred over the user web setting, I wonder?
J
Dave:
I poked around further and think that the ppi value is stored in the JFIF markers in SFW files. 100 ppi for Mac and 72 ppi for PC.
J
I was totally ignoring the density unit bit in my posts above. SFW JPGs are without ppi, and have an aspect ratio of 100:100 (which may be to suggest 100% viewing?).
NOT 100 ppi.
J
nothing matters on the web besides pixel dimensions.
100:100 == 1:1
nothing matters on the web besides pixel dimensions.
That and the ppi of your display. 😉
J
You mean the PPI of a few million displays!
(Assuming that many people want to see your web site. 😉
That and the ppi of your display.
yes and no. ALL images will default to that resolution so you can effectively cancel it out. pixel dimensions are all that count. (and save a couple of bytes worth of file size.)
sure you could save all your images at 72ppi or 92ppi or whatever, but that number is STILL going to be ignored and the image displayed at the monitor resolution.
