Understanding the Truth about PPI & DPI in Digital Photography

The misunderstanding about DPI (dots per inch) and PPI (pixels per inch) in digital photography, and it's perpetuation on the internet by YouTubers who know little of what they are talking about, makes my blood boil.

So here is a video that hopefully will put you all on the straight and narrow path to enlightenment!

The video is 25 minutes long, and you need to watch it ALL!

If you like it then please feel free to share it!

You will also want to watch a video by Guy Gowan - link below - that debunks the stupid and meaningless 300ppi/dpi myth that has become the so-called 'industry standard'.

#dpi #ppi #resolution

[MikaLatokartano]

Excellent. Finally someone who gives a clear explanation on the DPI PPI debacle. The industry certainly has done their very best to confuse people on the issue.

I only recently discovered your channel and every video I've watched so far has been of top quality. I'm quite astonished as to why your videos don't have more views. I suppose this is the day and age where extraneous, glossy factors lure in the masses and the actual quality of content seems to take on the role of an extra, but I am very pleased to have found a no nonsense channel by someone who has both deep and broad understanding of photography and post processing.

[shashankpandey]

Hello, First I would like to thank you for making this channel. I have learned a lot about rawtherapee from your videos. I would also like to ask a question that is related to the content of this particular video. I received instructions from a photo contest which is as follows:
" Use the link below to submit the high-resolution (JPEG or TIFF) and the original version (RAW) of your image so that we may verify its authenticity. The high resolution should be a minimum of 4000dpi on the longest side." I am having difficulty trying to understand this statement. Does it make sense to you Andy?

[joaniethatcher]

Go on with the rant. Made me stop to listen and I appreciate the information. It rather rocked my Epson printing world. I have a question about large format printing however. A 50” (long side) image... does the dpi drop in multiples of 8? Normally i would reduce dpi as the print grows (and accounting for viewing distance of course), but now I am wondering how to do the math. Would you be so kind as to elaborate on that? May I email you about this? Thank you for sharing your knowledge.

[chrislongley]

I agree with 99% of what you say. It boils my blood when people think the resolution or quality of their digital images has anything to do with the ppi or dpi as those are just labels. Where we would disagree is that you *can* (and we do) use the terms ppi or dpi interchangeably when talking about digital images. That is why in the print dialogue Adobe are using *ppi* _not_ dpi (eg at 13:05) to tell you how many pixels (from your image) will be spaced out along an inch of paper depending on your settings.

Confusingly printer manufacturers will talk about 1200dpi printing, that refers to the tiny dots of ink that combine with other tiny dots / droplets to reproduce one pixel in print. If a magazine asks me for a 10 inch wide image at 300 dpi or at 300 ppi I know in either case to send them an image that is 3000 pixels wide so there are enough pixels in my image to reproduce them spaced at 300 per inch.

Infact, to use your own argument against you, if ppi only referred to digital images and had nothing to do with printing, When would we ever use it or need it? As you showed, it makes no difference to the exported images. We wouldn't have the setting if it wasn't for printing.

[dennisrkb]

As a side note: The biggest revelation for me was to see a print under a microscope and realizing that a printer does not mix colors like a painter on their palette, but creates the illusion of different tones by cramming many tiny dots in a small space which then *visually* fuse together, similar to pointillism. That's also why you *need* many dots in a single pixel.

[fredrikhallen]

This was a very good video, thank you ! I have two qestions thou. As I have an Epson Stylus Pro printer myself, the 360 infor was very good, but where do you find this if you buy a new printer? And 360 * 8, can you give me more information on this, why not put 2880 dpi in the dialog directly?

[FrankEtchells]

Thank you Andy for a brilliant explanation on ppi and dpi... 👌