I want to shoot a few photos using the smartphone. I will receive JPEG files with a pixel density of 72 ppi. I will then move these photos to my computer and convert them from JPEG to TIFF (using GIMP, ImageMagick or something else).
During editing I don't want to use JPEG because JPEG has lossy compression. It affects on editing and artifacts. If I will edit photos I will save them a few times. If I do this with JPEGs, I will receive artifacts in it which I don't want; so I'll convert the photos from JPEG to TIFF.
In the next step I will edit these TIFFs: some of them I will crop, scale, rotate. In some photos I will adjust brightness and contrast (using GIMP, ImageMagick or something else).
I will then import the edited TIFFs to some software (LibreOffice Writer, Scribus or something else) in which I will arrange photos on pages and add few lines of text to each of them - explanation what is on the photo. On every page, I will arrange a few photos and text to each of them. I will have approximately 9 or 10 pages. I will then convert this file to PDF.
I will send this PDF file to a friend who will read it on smartphone or desktop computer using Adobe Acrobat Reader or something equivalent. Maybe he will want to print this PDF. In this case, the printed photos should not have pixelated, jagged edges.
What PPI I need to set for photos to avoid pixelated, jagged edges on paper?