Howdy all,
Hope I'm not missing something obvious with this - trying to save a PSD file (10X10 inches, 2000 pixels, at 200 dpi) as a PNG file. On doing so, and checkin image size properties, drops back to 72 dpi (which I know is not the end of the world) remains at 2000 pixels but JUMPS to 27.778 X 27.778 inches.
Any ideas or am i looking at a software error??
Many thanks folks..

Yup - it is normal and not a problem.
"Since your pixels get translated into dots of ink your goal is to make sure you have enough pixels for the product. Don't worry if your image editor shows a low resolution - as long as you have enough pixels. If you create an image at say 200 pixels/inch or 200 dpi and later you open the image and is shows 72 pixels/inch or 72 dpi is this a problem? No. It doesn't matter what it shows for pixels/inch or dpi as long as the number of pixels is correct."

http://www.tutortanith.com/imagesizing.htm

Really depends on how you're saving. If you "save as" it should be precisely those dimensions & resolution. If you "save for web" PS will resize it.
Not really a problem if you are using it for CP since their max print size is 10x10. But if you are trying to use it somewhere else where max print size is bigger... seems to me it could be a problem if you have it set to print at max size which is generally the default.

What do you mean by the phrase "resize it". When I "Save for Web" in CS2 the file is exactly the same dimensions in pixels as the original PSD.

Max print size is only 10 x 10 on some apparel. On plus size apparel it is 12 x 12. Throw pillows are 11 x 11, poster are considerably larger.

Well, in CS4 (also with CS3) I've found that if you make say a 2k x2k x 300dpi psd image, it's 6.667" x 6.667"

Fill it with all kinds of wildly colorful gradients like the rainbow and/or spectrum going in all kinds of directions to make it easier to see. (If your eyes start to bleed, stop. It's perfect!)

One copy save as png (No interlace) and it remains at precisely the same dimensions. And as crisp and clean as the original. (albeit smaller file size)

Now save (another copy of the same original psd) for web as png (I usually use bicubic) and it's extrapolated to 2k x 2k x 72dpi x 27.778" x 27.778". And again, even smaller file size then the png that was "saved as png". But since it's now 72dpi and nearly 30"s square, it will have a lot of banding and pixelation.

But NOTE here... Bridge shows them as the *same* size... but they aren't!!! By a longshot! Open them both and compare side by side. You'll be able to print the png or psd on a standard printer but there's no way you'll print the save for web png.

(NOTE #2... Have I mentioned lately that I always thought Bridge sucked?)

(Just in case... Bridge Sucks!!!)

Now for here (CP), generally not a "major" problem since this particular file will automatically be reduced by more than half for print. (Provided the template is what it calls for) The pixelation will still be there but not that noticeable. For other uses it may not be reduced as much so it can become a problem.

On the other hand, depends on the pic itself too. The test file above is really taking it to the extreme. If there are a lot of gradients, it can be a real mess even reduced for print. But none to very slight gradients or even just text... not much of a problem at all. Even "most" photos work well. Really depends on how you design. Plain and simple = ok. Wildly kaleidoscopic = a problem.

On the other other hand... could be I'm doing something wrong as well. But my designs can be quite intricate and I've always had this problem when trying to save for web.

Well ... I don't have any experience with your designs. I can only speak of my experience with my designs. Which is to say that the two methods are functionally identical in the CafePress environment with no difference in quality. Pretty much my experience with the actual images is consistent with my research on pixels and resolution as I describe in my "image size" information. That doesn't mean there aren't any ... there is always more to learn.

Since there is a file size difference between the two methods I can see that there is a possibility of functional differences that haven't been explained or described in the research resources I've found.

In general the explanation for viewing differences has to do with not printing quality differences but how an image is extrapolated for the screen. That is, a display monitor cannot possibly display any image at actually 300 ppi or 300 dpi because display screens aren't made with pixels that small. Most are 72 ppi or 96 ppi. *shrug*

I suppose that people who may be using png images in a print environment other than any POD might want to use the "Save As" method rather then "Save for Web" method. There are some articles out there describing this difference as avoiding the need to reset the resolution before printing, but none of the ones I read described this resolution reset as resulting in image quality differences.

Hay, don't get me wrong, Diane. Yer a card carrying guru! I've seen your tutes web pages and yer positively brilliant! You've opened my eyes in a myriad of areas.

But I've always had a little bit of a bone of contention for the save for web. Since one of it's "jobs" is to drop it to 72 dpi for a monitor it always made me wonder. After all, these files are actually for print, not for the web.

But, as you say, (and I agree) it prolly doesn't make much difference here since CP would have to "shrink" it anyway (maybe as much as 65%) since the dimensions are so huge. And it makes for a quicker upload since the files are quite a bit smaller to boot.

The only problem I see is that if CP ever decides to up their print area sizes it may create a problem. That is, say they introduce maybe... a blanket that has a 25" print area. Well, that save for web test file is over 27". So it would only have to be slightly reduced to fit and the quality would be pretty rough. But since the test file would "fit" we'd prolly start using older files on them not realizing the difference in quality. (Remember, the master psd test file was under 7") We end up with returns, CP ends up with returns. Nobody's happy.

Well, I'm not usually happy anyway, but I digress...

PNG is loseless, which means it does not dispose of any of its color information. CP could change its print area and as between the two methods of saving to PNG it would make no difference whatever. Both would behave identically. Seriously. That is what I try to go over in my tutorial.

An electronic file has no size, no dimensions at all, until it is applied. It is just a bag of color information and that information is fixed. In the electronic world we define it in terms of how that information is displayed. One dot of color=one pixel.

Try this. Take your psd (200 or 300 dpi) and save it each way. Open both files in Photoshop. The "Save for Web" will either be 72 dpi or 96 depending upon your system. The other should be the higher dpi as originally created. Now go to "view" and click on "Actual pizels" for each of the two files. In my tests doing that shows me identical images. I can't look at one or the other and guess which is set to 72 dpi and which is 300 dpi. There isn't, in my files, any difference at all. Is there in yours when each is viewed at "actual pixels"?

The image size information 72 ppi vs 300 dpi only matters to some applications. Some applications rely on the label on the bag to determine how big to make the print area. CP always does it the other way. It determines the print area and pours the contents of the bag to fill it. The choice of save methods won't make any difference because their color information is identical. You either have enough in the bag, or you don't. Regardless of whether CP makes increased image areas every image that is 2000 x 2000 pixels will have the same benefits or problems. The label on the bag just will never matter.

Well, yeah. That's what I'm saying with the test file, Di.

The 72 dpi file is a mess because of the extreme gradients. It is lossless but it's display size is being enlarged 5 times it's original size by the web conversion process. PS does do an amazing job in that respect "unless" it has to play with a lot of gradients, drop shadows, bevels etc. That's where it drops the ball and starts to break down.

But again... that test file was going to the extreme with the wild gradients allowing one to see the difference. (I can send you a link to compare what I did with the test file if you'd like) If the file isn't wildly intricate it probably won't be really noticeable at all, especially if it's reduced back down by 5 times its size for print. And even less noticeable if it's going on fabric.

Even most photos work pretty well. But there will be a difference. Each design will render differently. In fact if you take that wild test design and insert some kind of photo in the center and save for web, the photo will still look just about perfect. (maybe just a tad softer) But the gradients, bevels and any wider drop shadows you may use will still pixelate and you'll see some banding in them. In my experience, some designs (maybe most) will work, some won't. Solid colors generally work fine. Gradients, shadows and bevels can be really problematic. Really depends on one's design and design style.

Personally, I imagine most of my stuff would work with save for web. But every once in a while there's that odd ball that comes up. So do I think about how to save each file? Nah, not enuff gray matter and I get headaches easy. So even tho they are larger file sizes, I automatically just save as with everything. But... that's me.

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And a FWIW... (a bit off topic) dunno why there isn't a warning (outside of the size warning) when saving png to web. Outside of being a larger file than gif or jpg (Smaller is always better. Think page load time.) there's a good reason you never see them on big sites like amazon, walmart or even CP. Even tho we upload png's to CP, they're all converted to jpg for the web pages.

While they "sometimes" look better, png is a recent format. Older browsers will not render them. Obviously every one's clientel is different but my stats show as many as 25% of my visitors have older browsers. Anyone using a browser from around the time of the IE6 era will see... absolutely nothing. The png format didn't exist then so those browsers don't know how to render it. So they skip them. For a personal web page... no big deal. For a business site... it's like shooting yourself in the foot. They're looking at a page with no pics whatsoever.

So if someone is using png's exclusively on their site they could be throwing a pretty sizeable amount of sales away. IMHO, PS should also give a "Warning, png files will not display in older browsers".