Question about 'print size' and sharpening in PS

When sharpening and editing photos, I'm not sure if this is correct, but I've heard it's best to sharpen images in "print size".

I usually set my images to 12x8in at 300 resolution, but when I hit the zoom tool then 'print size' up at the top, the image displayed is much smaller than a 12x8.

I feel like I'm just not getting something. If the image represented is smaller than an actual 12x8 image, how can I be sure that I'm sharpening correctly to fit that size of a print.

If someone could point me in the right direction, I would appreciate it.

How big in inches does it actually display at?

And, what is the resolution and dimensions in pixels it shows?

If I put a ruler up to my screen, its 7.75x5.25in.

The pixel dimensions of my images are 3600x2400.

Well, not sure what's going on, unless Photoshop is using a crazy figure for its screen resolution to use when displaying a document (my preferences use an approximate value of 100 ppi to juggle between two screens).

I open an image and check Image/Image size and one opened at the default ppi of 240 and showed the dimensions in inches to be around 10x15 or so (I had to run upstairs and interrupt someone to do this and run back down here so it's an approximation) and when I clicked the zoom tool and chose Print size it opened a window, the image was enlarged to the proper approximat size in inches, although it over-filled the window so you have to scroll to see it!

Hmm... This is frustrating me.

That's the key point. Are you seeing all the image or only a 7.75 x 5.25 section?
At any rate, that print sized zoom is not much used since the quality of the display is not as good when the resize calculations are complicated by needing a 29% or a 37% zoom. The easy ones, 50% (1/2) or 25% (1/4) are better, use them to get an approximation of print sharpening and/or noise - monitor pixels don't behave like ink drops on paper.

tzalman wrote in post #11877356
That's the key point. Are you seeing all the image or only a 7.75 x 5.25 section?
At any rate, that print sized zoom is not much used since the quality of the display is not as good when the resize calculations are complicated by needing a 29% or a 37% zoom. The easy ones, 50% (1/2) or 25% (1/4) are better, use them to get an approximation of print sharpening and/or noise - monitor pixels don't behave like ink drops on paper.

I did some more lurking around, and this is exactly what I found. Thanks for reaffirming this!

pxchoi wrote in post #11877388
I did some more lurking around, and this is exactly what I found. Thanks for reaffirming this!

Are you saying you saw only the portion of the image that fit into the "normal" window and that you could scroll to see the whole image? If so, that's normal, since the image is too big to view all in the same window!

What is your screen size and resolution and what setting do you have in

Edit/Preferences/Units and Rulers

Screen Resolution

It should be

Measure the width of your screen and divide it by your horizontal resolution setting.

I believe Photoshop defaults to 80 or something around there which is not high enough for your typical LCD panel.

tonylong wrote in post #11877573
Are you saying you saw only the portion of the image that fit into the "normal" window and that you could scroll to see the whole image? If so, that's normal, since the image is too big to view all in the same window!

No, people were saying that I should look at the screen at 25, 50, and 100% to get a better representation of sharpening.

bohdank wrote in post #11878403
What is your screen size and resolution and what setting do you have in

Edit/Preferences/Units and Rulers

Screen Resolution

It should be

Measure the width of your screen and divide it by your horizontal resolution setting.

I believe Photoshop defaults to 80 or something around there which is not high enough for your typical LCD panel.

My 'Print Resolution' = 300, 'Screen Resolution' = 72, and 'PostScript' = 72 points/inch.

I changed the screen resolution to 110.77 (1440/13) and now when I hit print size it comes out in the correct size. Thanks!

pxchoi wrote in post #11878739
No, people were saying that I should look at the screen at 25, 50, and 100% to get a better representation of sharpening.

100% only; that is pixel-for-pixel on your monitor.

All other views are interpolated, so you cannot be sure what you have.

To know what you'll have in print, you have to print it.