Picture resolution/Photoshop question

Started Apr 28, 2017 | Discussions thread
richardplondon
richardplondon Forum Pro • Posts: 10,694
Re: Picture resolution/Photoshop question
1

Toermalijn wrote:

Jestertheclown wrote:

Toermalijn wrote:

Jestertheclown wrote:

Toermalijn wrote:

sabrina81 wrote:

guiri wrote:

She had someone take a few pics of her product and send them to me. I checked the exif info and they are 300 dpi. They look great when I zoom in and yes, I know they need to be 72 dpi on the web.

Resolution (ppi, not dip) is completely irrelevant to sizing photos for the web. The only thing that matters is pixel dimensions.

These "two" images will look exactly the same on the web or when viewed in any image viewer:

Right. But OP was speaking about 300 vs 72 dpi. If you print the image it's a total different matter. At the same size, a 300 dpi image has way more detail in the print then a 72 dpi image.

That's "ppi, not "dpi".

I think it has more to do with scaling in Photoshop vs ACDsee.

Anything over the actual pixel size(100%) will yield jagged edges in the zoomed image in Photoshop.

Also read:

https://www.dpreview.com/forums/thread/179047

About the jagged edges.

Excerpt of the OP:

She had someone take a few pics of her product and send them to me. I checked the exif info and they are 300 dpi. They look great when I zoom in and yes, I know they need to be 72 dpi on the web.

He is clearly speaking of dpi!

Yes, you can set dpi for printing in the print(er) preferences. If you set it to best or 600-1200 or whatever you change the dpi settings. So, if you print in photoshop and in that module you go to the the printer settings you can actually change the dpi setting from within Photoshop.

Thanks. I stand corrected!

So changing the resolution to 300ppi and setting the printerdriver/settings to best (high dpi) yield the best printing results. Some high end printers can do that on the fly by pressing a button to change dpi.

In photoshop changing dpi:

http://www.rideau-info.com/photos/changedpi.html

Also read this:

difference between dpi and lpi:

I already know the difference.

Sadly, many others don't.

http://www.sos.com.au/index.php/tips-info/dpi-vs-lpi-whats-the-difference/

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So true, hence the confusion.

The moment I see dpi, I think printing.

People who learnt about resolution chiefly in relation to manipulating an image based on a constant defined physical print size, often have a tendency to think of a monitor as a quasi-print medium with a hardware resolution of 72dpi.

They may think of different versions of an image, in terms of e.g. one which is "FOR" 300dpi output, and another which is "FOR" 72dpi output.

So we can say, it is more of a print MENTALITY to conceive of image sizing in DPI terms.

The misleading thing for these people when it comes to preparing images for web, is that the underlying concept is not so applicable - you don't have any fixed physical image sizing, and you don't have any knowledge of the hardware being used.

Actually, historical note, at one time Mac displays DID have a standard hardware resolution of 72dpi specifically; and bitmap fonts which assumed this; and not only graphics applications but also desktop publishing (such as Pagemaker) used to rely on this directly too. So one could lay out both images and typography according to common "point" based dimensioning, with a point defined neatly as 1/72nd of an inch, and therefore corresponding to one monitor pixel. Smart resizing of images used to constrain according to this same size measure. And viewing a file at 1:1 zoom size so far as its content and pixels, would be the same thing as viewing it at its intended physical size for print.

And a close association has endured of a "72dpi" output intention, with on-screen display - even though screens now have a varying, and rather higher, hardware resolution than that.

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