Sorry, I'm still not getting the resolution/ppi thing

j-bo

Try as I might by reading, I still am confused.

I used to do most of my editing in picasa, where it didn't ask for a ppi setting and I don't know what the default was.

Using Adobe CS2, on image size, you choose ppi and mine is defaulted at 72 ppi. I've just been saving them at this and 12 (max) and uploading. Reading, it looks like a 10 would be just fine.

I read this http://www.smugmug.com/help/print-quality over and over and am still lost.

When using CS2 and saving my images, do I need to change the defaulted 72 (web viewing) even though the pixel size is 2304x3456, to 150ppi or ??

I keep reading where they will uprez or downrez accordingly, but don't know if that is from the 150ppi or any ppi.

Should I be uploading all mine at 150ppi or what is the ultimate resolution?

I know its been gone over and I've read some of the searched threads and I'm still confused.

jfriend

Ignore the ppi

j-bo wrote:

Try as I might by reading, I still am confused.

I used to do most of my editing in picasa, where it didn't ask for a ppi setting and I don't know what the default was.

Using Adobe CS2, on image size, you choose ppi and mine is defaulted at 72 ppi. I've just been saving them at this and 12 (max) and uploading. Reading, it looks like a 10 would be just fine.

I read this http://www.smugmug.com/help/print-quality over and over and am still lost.

When using CS2 and saving my images, do I need to change the defaulted 72 (web viewing) even though the pixel size is 2304x3456, to 150ppi or ??

I keep reading where they will uprez or downrez accordingly, but don't know if that is from the 150ppi or any ppi.

Should I be uploading all mine at 150ppi or what is the ultimate resolution?

I know its been gone over and I've read some of the searched threads and I'm still confused.

More than 99% of the time, you can completely ignore the ppi setting (just like Picassa did). This is truly one of the most confusing aspects of Photoshop for photograhers just looking to make an 8x10 print. The ppi value is just a piece of metadata on your image and as long as you tell your printing software what output size you want the image to be scaled to (e.g. 5x7 or 8x10), that ppi setting is completely ignored.

Except for the caveats below, I ignore this value in Photoshop.

There are a few caveats in Photoshop related to the ppi setting and the related image size (e.g. 8" x 10").

• If you are going to use fonts in your image (captions, labels, etc...), you do need to pay attention to the labeled size of your image because Photoshop uses that value to know how large to display a given size font (e.g. a 12 point font).
• If you are using the crop tool and you do not want to resample your image (e.g. you just want to crop without changing the remaining pixels), then you must clear the ppi value from the crop tool before cropping. If you don't clear it, then Photoshop will assume you want to crop AND maintain a given ppi so it will resample your image to keep the same number of pixels (even though you cropped some away)
• If you want to know whether you have enough pixels for a given print size, you can sometimes look at these values and let Photoshop do the math for you. Even here, you don't need to use this value. You can always just take your print dimension divided by your pixel dimension (e.g. 2008 pixels / 10" = 200 ppi) to do your own calculation for whether you have enough pixel resolution for a given print size.
• If you want to resample your image, you can do so with the crop tool by manipulating the ppi value. I'd rather avoid the confusion and just use the Image Size command to resample my images. That command also gives you more control over things like the resampling algorithm.
• If you ever use a printing service or a printing application that doesn't let you specify the output print size and requires that it be labelled on the image. In that case, what you need to make sure is right is not the ppi, but the labeled size of the image. No web printing service that I know of works this way and nearly all PC software has been updated to let you specify the desired output size so this almost never comes up.

j-bo

Nice and detailed and ... too techy for me. Let me see if I get it. I want all my photo's to be able to be printed up to 20x30 as that's usually the max size. No, I don't want to turn on proof delay.

No cropping method:
Open Image "1234"
Do my editing (no cropping)
Save as "1234 new"
Save at "10" or maximum of "12" ? It's a question as I've been doing all at 12, but would like the smaller file size if prints are just as good at 10.

Cropping:

Open Image "1234"
Do my editing with cropping
Go to image size and change ppi to ______(252?) or clear the ppi space before I crop?
Save as "1234 new"
Save at "10" or "12" ?

So, I guess to simplify. Don't worry about the ppi when using CS2 except if I crop a photo?

The other scenario's you list don't apply to what I do.

Thanks for helping!

ivar

Hi

You are not the only one who finds the PPI confusing. Not too long ago I was totally confused by it myself. I've learned simply to ignore it for uploading and printing with SmugMug, and it works wonders

I open my files in PS, do whatever I want to do with them, do not resize them, and save them with Quality 10, which is lab-quality. Very few people can see the difference between 10 and 11, and even fewer if any can see the difference between 11 and 12.

I hope this helps.

j-bo

ivar wrote:

I hope this helps.

More than you know!! As I noted, in Picassa I didn't worry about it at all, and now so it seems, I won't worry about it in CS2 either! Thanks for insights and help.

colourbox

THere was a good article on this today:
The Truth About Resolution

It isn't the last word on the subject, but it's good on the basic relationships.