More questions about resolution, and more

[Djuna_A_]

HI there, please bear with me as I am just learning the jargon.

I have some Jpeg files in my iPad photo app and some RAW files on my iPhone.

They are all slated to be printed in a book in CYMK format.

I want to edit them Lightroom Mobile, for the auto functions and for ergonomic reasons, then in Photoshop on my Mac.

A few questions about resolution:

When I mail the JPEG files from my iPad to my email and then download them, does the resolution change?  I know I should have exported them directly into a Photoshop app, but I didn't, (this was before I knew about lossy formats), and since there are many shots of each painting, I chose the one I had edited in the Photo app, reverted it to original so that the original ppi would be there, and then mailed them to myself.  I can no longer distinguish which one I chose.

When I open the RAW files in (the updated version of) Lightroom Mobile, I am given two pixel readouts:  a first, e.g. 2677 x 3200, and then a second in  parenthesis, which is a bigger value.  Is the first one ppi and the second file size?

I am not given the option to export the edited Lightroom file into Photoshop directly, so I open it in Photoshop Fix.  The pixel readout is the higher number, the one in parenthesis.  Did I lose ppi?

And while I'm at it, is there a way to export files directly from Lightroom Mobile into Photoshop?

Thanks!

[JJMack]

PPI is a physical thing it is the size of the pixels the image is to be rendered with. Pixel density Pixels per inch.  The thing is Displays do not honor image resolution.  Displays are manufactured with one size pixels.  Printers can render Images using the correct pixels size Displays can not.  The Resolution setting you see for printers is not a about pixel size its a pixel qualitysetting.  Higher resolution smaller droplets of ink are  user to paint in you image pixels using ma colored droplets of ink.  The higher setting you use the better  your images larger pixels will be rendered.

[Djuna_A_]

What are you referring to when you say "Displays?"

[Per Berntsen]

To add to what JJMack said - ppi (pixels per inch) is metadata that printer drivers use to calculate the printed dimensions. Ppi is not an indicator of image resolution or quality, the important numbers are the pixel dimensions.

So if you have a 2400 x 3000 pixel image, 300 ppi, it will print 8 x 10 inches, because 2400:300 = 8 and 3000:300 = 10.

If the ppi is 72, it will print at 33.33 x 41.66 inches.

I don't use Lightroom mobile, but I suspect that the numbers in parenthesis are the actual dimensions, and that LR mobile only works with a smaller version of the original. Personally I would not use a reduced functionality app like LR mobile or Photoshop Fix for editing work that's going to be printed, but do everything in Photoshop.(or Lightroom/Photoshop)

[JJMack]

What you are look at right now your LCD Display not your printed image.  Computer displays phone displays tablet display etc have fixed size pixels some have more pixel the others and some have different aspect ratios.

[Conrad C]

https://forums.adobe.com/people/Djuna+A.  wrote

When I open the RAW files in (the updated version of) Lightroom Mobile, I am given two pixel readouts:  a first, e.g. 2677 x 3200, and then a second in  parenthesis, which is a bigger value.  Is the first one ppi and the second file size?

I just checked some of my own images in Lightroom Mobile and it looks like the first number represents the pixel dimensions after cropping, and the second number in parentheses represents the uncropped, original image dimensions.

About your original question, just emailing images shouldn't change their resolution (ppi) or pixel dimensions (w x h). If either changes, it might be because of the email program; for example, Apple Mail has a setting for the image size of the attached photos so if you want to preserve the image's current pixel dimensions, you must set that to Actual Size.

[gener7]

https://forums.adobe.com/people/Djuna+A.  wrote

When I mail the JPEG files from my iPad to my email and then download them, does the resolution change? 

As resolution is basically print metadata, I have seen where email servers throw away that information. So if your jpeg is 8 x10 @300 ppi, the client is going to tell you they got it as a 33 x 41 @ 72 ppi which is what image files default to if that information is missing. Same pixel dimensions, just spread out, leaving you both wondering what happened.

So I would suggest looking for a solution in Dropbox or WeTransfer where you email the link and the client can download it safely.

I won't even go into the 10-15 MB limits on your files. In fact I would ask you to zip them if you must email.