# 72 PPI HELP?!



## kitkatdubs (Nov 13, 2016)

I am running into an issue with PPI  - I import my RAW files into PS and it says "300 PPI" at the bottom.  I edit my photos and then export them and it still says "300 PPI".  However, today I decided to fix something on a photo and so I pulled it back into photoshop, the jpeg file and I noticed that it says 72 PPI not 300.  WHY is it getting changed?  I am so confused?!?!?!  HELP!  I edited 3 sessions and am just noticing this now?!!!!!!


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## fundy (Nov 13, 2016)

The property of image in your computer is a resolution (like 6000x4000 pixels). 
The PPI (pixels per inch) is not relevant until you actually print the picture - it is the resolution divided by physical size of the picture. And it tells you the picture's puxel density.

Odesláno z mého UMI_MAX pomocí Tapatalk


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## kitkatdubs (Nov 13, 2016)

fundy said:


> The property of image in your computer is a resolution (like 6000x4000 pixels).
> The PPI (pixels per inch) is not relevant until you actually print the picture - it is the resolution divided by physical size of the picture. And it tells you the picture's puxel density.
> 
> Odesláno z mého UMI_MAX pomocí Tapatalk




Ok, so this obviously matters if my clients will be printing the photos.  They need to be at 300PPI and no matter what I do, I can't export the photo at 300 PPI... its like PS is changing it!?


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## KmH (Nov 13, 2016)

Do you use a Canon camera?

You can set the print resolution (PPI) in Photoshop:
Image > Image Size - before export.
However, you may want to note that a print lab will change the print resolution as needed according to the size print ordered, regardless what you have set the print resolution to.

Because as fundy pointed out, print size is a function of the image resolution ( xxx px by xxx px) and the print resolution (pixels per inch - ppi).
Also mote that the ppi (print resolution)is meaningless for electronic display, because the resolution (and aspect ratio) of electronic displays can easily be changed.

It's likely your clients are even less informed regarding the ins and outs of having prints made.
Which is why it gets scary when one thinks about clients making prints on their own, or having print made when it comes down to image resolution, print resolution, print and image aspect ratios, and color management.

By the way - 300 ppi is a rule of thumb- not an absolute.
At some point as print size increases the print resolution has to be reduced to make the print because there is insufficient image resolution to make the print at 300 ppi.

300 ppi works OK for smaller print sizes but note for large prints. Which is why the best print labs minimum print resolution requirement is as low as 100 ppi.


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## TCampbell (Nov 13, 2016)

kitkatdubs said:


> I am running into an issue with PPI  - I import my RAW files into PS and it says "300 PPI" at the bottom.  I edit my photos and then export them and it still says "300 PPI".  However, today I decided to fix something on a photo and so I pulled it back into photoshop, the jpeg file and I noticed that it says 72 PPI not 300.  WHY is it getting changed?  I am so confused?!?!?!  HELP!  I edited 3 sessions and am just noticing this now?!!!!!!



You'll be a much happier person if you just ignore PPI.  It's a meaningless piece of metadata that doesn't change anything "real" about the image.  It's just a tag. You may as well set the PPI to "airplane" and it would be every bit as meaningful as any numeric value you assign.

Your image has some REAL number of pixels in it.  The "PPI" label in the non-visible part of the file (meta-data) is JUST a label.  Some software which _chooses_ to not ignore it (because you can totally ignore it) might use that value to say "Oh hey... this person wants the image to display on a monitor such that every 72 pixels in this file should be spread out nicely across each one inch of the display".    This begs another question which is... does that software actually KNOW how many pixels reside within every inch of the display?  Usually not.  In order for the value to be meaningful, typically YOU have to know the geometry of the specific digital device that will be used for display and then YOU can set the value in the file so that you know how much of the display real estate will be occupied by the image.

Many years ago, the 72 PPI value was used because the dot-pitch common to so many monitors allowed about 72 pixels per inch of screen.  But that's not really true anymore.  I have a 27" 5k display... it has a PPI of 220.  So if you were assume that 72dpi made up one inch on my display then I'd get an image about 1/3 as wide and high as what was intended. 

Think of the PPI as a "request" that doesn't actually have to be honored.  It has nothing to do with your image quality or your file.  If you want to change the quality of the file then you'd bring the software into something like Photoshop and ask it to "resample" the file.


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## kitkatdubs (Nov 13, 2016)

Can I go back and change the photos from 72 PPI to 300 PPI??


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## john.margetts (Nov 13, 2016)

kitkatdubs said:


> Can I go back and change the photos from 72 PPI to 300 PPI??


You can, but as you have been told above, there is no point. Just ignore it.


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## kitkatdubs (Nov 13, 2016)

TCampbell said:


> kitkatdubs said:
> 
> 
> > I am running into an issue with PPI  - I import my RAW files into PS and it says "300 PPI" at the bottom.  I edit my photos and then export them and it still says "300 PPI".  However, today I decided to fix something on a photo and so I pulled it back into photoshop, the jpeg file and I noticed that it says 72 PPI not 300.  WHY is it getting changed?  I am so confused?!?!?!  HELP!  I edited 3 sessions and am just noticing this now?!!!!!!
> ...




Very interesting Tim!  SO my export settings say that the screen resolution is 72, but print is 300.  Does that mean it will be 300 PPI then?  I'm so confused b/c when I pull the photo back into photoshop after exporting, it says 72.  But does that mean really is 300 for print?  Check out my screen shot?  So should I be "Saving As" instead so it doesn't change the PPI?


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## Ysarex (Nov 13, 2016)

kitkatdubs said:


> fundy said:
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> > The property of image in your computer is a resolution (like 6000x4000 pixels).
> ...



No in fact it doesn't matter.





That's the same image at two different PPI values. The PPI value has no effect on the actual image pixel dimensions. It is simply recalculated when you change the print size.



kitkatdubs said:


> They need to be at 300PPI and no matter what I do, I can't export the photo at 300 PPI... its like PS is changing it!?



The PPI will change at time of printing when the print size is specified. PPI is pixels per inch. Change the number of inches in the print and the number of pixels per inch has to change if you have a fixed number of pixels.

Joe


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## kitkatdubs (Nov 13, 2016)

Ysarex said:


> kitkatdubs said:
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Ok got it!  Thank you- what I am now trying to understand is it says when i export it screen is 72 PPI, however print size is 300 PPI ... does that mean its still 300 PPI?  Even though when I pull it back into photoshop its 72 PPI.  HAHAH AHHHHH Can someone call me on the phone and talk to me about this, seriously!  I need some help!


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## kitkatdubs (Nov 13, 2016)

Most of my customers are printing thru tiny prints or shutterfly for holiday cards and their PPI recommendation is 300, which I haven't given them b/c I just realized now it says 72 or is it really 300 PPI b/c it says print resolution is 300PPI for my screen, right?  Am I reading that right?


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## Ysarex (Nov 13, 2016)

kitkatdubs said:


> Ok got it!  Thank you- what I am now trying to understand is it says when i export it screen is 72 PPI, however print size is 300 PPI ... does that mean its still 300 PPI?



It was never 300 PPI to begin with. It is no PPI until it is coming out of the printer. If there is no physical printer in front of you and that printer isn't spraying ink on paper that is moving through the printer then there is NO PPI.

PPI becomes real when print size is specified and not until then.

Joe



kitkatdubs said:


> Even though when I pull it back into photoshop its 72 PPI.  HAHAH AHHHHH Can someone call me on the phone and talk to me about this, seriously!  I need some help!



You're worrying about something that isn't real.

PPI doesn't change anything it tells you something.


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## Ysarex (Nov 13, 2016)

kitkatdubs said:


> Most of my customers are printing thru tiny prints or shutterfly for holiday cards and their PPI recommendation is 300, which I haven't given them b/c I just realized now it says 72 or is it really 300 PPI b/c it says print resolution is 300PPI for my screen, right?  Am I reading that right?



When your customer picks a print size in the software at their computer the PPI will change right then and there. If you set it to 10,000 PPI it wouldn't matter one iota. As soon as they select a print size the PPI will change.

The print company will decide to leave it alone or modify it and they'll not tell you.

Joe


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## kitkatdubs (Nov 13, 2016)

Ysarex said:


> kitkatdubs said:
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> > Ok got it!  Thank you- what I am now trying to understand is it says when i export it screen is 72 PPI, however print size is 300 PPI ... does that mean its still 300 PPI?
> ...




But it matters to the clients b/c they will be printing these...


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## kitkatdubs (Nov 13, 2016)

So last year, I had a client print thru Tiny Prints and they came back to me saying the photo was very blurry.  Tiny Prints called me and explained that it was at 72 PPI and needed me to change it to 300 PPI.  I do not want that to happen again this year..


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## Ysarex (Nov 13, 2016)

kitkatdubs said:


> So last year, I had a client print thru Tiny Prints and they came back to me saying the photo was very blurry.  Tiny Prints called me and explained that it was at 72 PPI and needed me to change it to 300 PPI.  I do not want that to happen again this year..



Look at my first post and the graphic. I circled in red a box titled resample -- that's Photoshop (CS6). That could be the issue. That should be checked off by default. When that is checked off changing PPI is meaningless. But it is possible to have an accident and check that on and not realize it. Then you could make a change that would lower the resolution of the original photo.

Joe


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## Ysarex (Nov 13, 2016)

It's easy enough to verify if you're resampling an image by accident. PPI means nothing without print size specified. Again look at the graphic in my first response. When the PPI changed the print size changed. In that case PPI is meaningless because when the print size changes back the PPI changes back. What you don't want to see happen is the PPI change and the print size stay unchanged. That would be a resample which would in fact do harm to your photo.

Joe


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## kitkatdubs (Nov 13, 2016)

Ysarex said:


> It's easy enough to verify if you're resampling an image by accident. PPI means nothing without print size specified. Again look at the graphic in my first response. When the PPI changed the print size changed. In that case PPI is meaningless because when the print size changes back the PPI changes back. What you don't want to see happen is the PPI change and the print size stay unchanged. That would be a resample which would in fact do harm to your photo.
> 
> Joe



Wow so interesting!  I did not know all of this.  Yes, the resample box is checked off, so it should be fine.  How can I check past photos if I kept "resample checked " though?


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## kitkatdubs (Nov 13, 2016)

Is this what it should look like?  Do i want it to resample "Automatically" or Bilinear?  OR some other setting?


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## kitkatdubs (Nov 13, 2016)

See Below


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## Ysarex (Nov 13, 2016)

kitkatdubs said:


> Ysarex said:
> 
> 
> > It's easy enough to verify if you're resampling an image by accident. PPI means nothing without print size specified. Again look at the graphic in my first response. When the PPI changed the print size changed. In that case PPI is meaningless because when the print size changes back the PPI changes back. What you don't want to see happen is the PPI change and the print size stay unchanged. That would be a resample which would in fact do harm to your photo.
> ...



Look at the pixel dimensions. What's the resolution of your camera? pixels by pixels. For example to make that graphic I posted I had to open a photo. My camera's resolution is 6000 by 4000 pixels -- 6000 x 4000 = 24,000,000 a 24 megapixel sensor. I did a little cropping to that photo and my final result was 5314 x 3751 pixels. I'm going to make sure from that point on that those pixel dimensions don't ever change.

Joe


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## kitkatdubs (Nov 13, 2016)

Ysarex said:


> kitkatdubs said:
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I'm shooting on a Canon Mark IV - so I believe its  6720 X 4480 - so if i check all the photos from the session and they are all 6720 X 4480, then I am good to go, correct?


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## Ysarex (Nov 13, 2016)

kitkatdubs said:


> Is this what it should look like?  Do i want it to resample "Automatically" or Bilinear?  OR some other setting?



You  *NEVER EVER *want to resample. OK, that's a little extreme, but just a little. For example when post a photo here on the forum I make a duplicate and resample it down to about 1000 x 700 pixels -- scren display. But that's a dupe for display. My original is not getting resampled *NEVER.
*
Joe


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## kitkatdubs (Nov 13, 2016)

Wait, so the box SHOULDN'T be checked?


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## Ysarex (Nov 13, 2016)

kitkatdubs said:


> Ysarex said:
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Correct. Consider that you may have cropped a photo and so it could 5000 x 3300 or something. That's fine. If you see a photo that's 1000 x 700 or less then you've got a problem.

Joe


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## kitkatdubs (Nov 13, 2016)

kitkatdubs said:


> Wait, so the box SHOULDN'T be checked?



Would you be interested in calling me hahah?


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## Ysarex (Nov 13, 2016)

kitkatdubs said:


> Wait, so the box SHOULDN'T be checked?



*NEVER!!! check that box! *Unless like I said you're prepping a duplicate to put on th web or something.

Joe


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## kitkatdubs (Nov 13, 2016)

Ysarex said:


> kitkatdubs said:
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> > Wait, so the box SHOULDN'T be checked?
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 you mean uncheck that box hahah


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## Ysarex (Nov 13, 2016)

kitkatdubs said:


> Ysarex said:
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Never resample an image.

Joe


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## kitkatdubs (Nov 13, 2016)

Ysarex said:


> kitkatdubs said:
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can i call you???


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## Ysarex (Nov 13, 2016)

kitkatdubs said:


> kitkatdubs said:
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> > Wait, so the box SHOULDN'T be checked?
> ...



You can call me 314-xxx (leaving house soon so now.)

Joe


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## KmH (Nov 13, 2016)

Canon cameras by default set the ppi to 72.
Which is why I asked if you use Canon cameras.


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## kitkatdubs (Nov 13, 2016)

KmH said:


> Canon cameras by default set the ppi to 72.
> Which is why I asked if you use Canon cameras.



Can I change this?


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## KmH (Nov 13, 2016)

I don't think so, but I'm a Nikon shooter.
Check the User Manual for your camera.


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## photo1x1.com (Nov 17, 2016)

Ysarex said:


> kitkatdubs said:
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Thanks, great info. I didn´ know about the box and always copied the pixel dimensions width, changed the ppi and then pasted the width back in again to keep the pixel count the same. You never stop learning.

In regard to dpi in general, even graphic designers and some printers don´t know what it really means. I do some graphic works for a client from time to time and his printers always ask me for 300dpi. I then say 300dpi AND...??? They don´ know the answer, but they need to tell you the final print size along with the desired dpi. Otherwise it is similar as if you´d go to the grocery and ask for 300 Salami instead of 300 grams Salami.
I even created a page on my website where I show them the difference - it is in german though, so not worth posting here - but this is an image from the page: both images are 300dpi - you see, it doesn´ tell you anything without knowing the size:






To be on the safe side, always send the full resolution to the printers.


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## Ysarex (Nov 17, 2016)

photo1x1.com said:


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No, both images are 300 PPI not DPI. "P" is for pixel and "D" is for dot. You only have a dot when you have ink on paper. Printers print dots and photos are made up of pixels.

Here's another way to display the point that PPI has no meaning without the size specified. "I" is for inch.



 

 

"To be on the safe side, always send the full resolution to the printers." Absolutely! Both of those photos I just posted have a resolution of 212 X 328 pixels.

Joe


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## john.margetts (Nov 17, 2016)

I had a similar problem with my local lab who insisted they scanned negatives to give a print at 300 ppi. They still think they do but they no longer mention it to me.


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