PPI Does Matter!!!

Hey gang!

A couple days ago someone asked a question in another section that triggered all the standard discussions about things like image size/resolution and the standard phrase that "ppi doesn't matter".

All was going well until somebody, an experienced photographer and a long-time POTN member and friend of the community, posted something wild and crazy that stirred up an entertaining and interesting discussion!

I thought the "regulars" here in R,PP&P might like to play with this!

So first, I'm going post a link to a post he made with a couple pictures, and I'd like you to check them out. Then, before you open up the thread, pop in here with your first impressions (if you are like me it will be something like "that's crazy! What kind of silly stuff is he doing to those shots and trying to pull on us?!".

https://photography-on-the.net …p?p=12310802&po​stcount=18

Then, you can read the rest of the thread -- the first posts are, like I said, pretty "standard" except for the interest thing that brought the question up, but then at about post #15/16 it starts to get interesting and entertaining -- so you can cut to the chase by just going to #16 if you want!

Let's have fun with this!

ppi does matter for print while for web, only the pixel dimension.

Link?

nonameowns wrote in post #12324283
ppi does matter for print while for web, only the pixel dimension.

Ah, but did you see the post I linked to? They were Web images...!

I can't see a link ...

Oh man, I'm sorry, I didn't get that in!

Well, I edited the original post and put it in. Here it is:

https://photography-on-the.net …p?p=12310802&po​stcount=18

That thread is silly to say the least. DPI is for printing only and obviously has no effect on pixel dimension of the image. PPI is determined by the physical dimensions of the screen each of us is looking at. Image size in pixels divided by the length of the screen the image occupies equals PPI.

This whole woodoo multiplying, dividing of pixels, saving and resaving images reshaped into blocks (that you think are pixels) do not change anything and just waste your time and confuse others.

You might also find this to be an interesting read.
http://www.rideau-info.com/photos/mythdp​i.html.

But I think frenchconnector pretty much summed it up good enough already.

I'm a little confused about that thread too...

technically, PPI doesn't matter if you're viewing on the computer/web right? Since it's based on the resolution. So no matter what you do to PPI (assuming you're only changing PPI), it has no affect on the image visually (resolution is still the same).

When you change the PPI and resample to change the dimensions (because you want to print at a certain size at a certain resolution), then that's when it matters. Although, I don't think it would be nearly as bad as the other thread is showing (since it's a very drastic and unrealistic resolution you're resampling from).

In the end, I guess what I learned from the other thread is that, 40x27 pixels images are horrible if you want to print them at 4x6 @ 200 PPI. So don't print from your thumbnails people! :P

OTOH, if you print them at 40x60 inches, it's art.

ohata0 wrote in post #12326092
So don't print from your thumbnails people! :P

No program worth its salt will actually print the thumbnail because you selected it and invoked the Print command.

It will use the full image file, of course.

I just looked at the link (https://photography-on-the.net/forum/...2&pos​tcount=18)...very blurry looking picture. So what is the point?

[edit] I just looked at two posts down in the same thread, https://photography-on-the.net/forum/...2&pos​tcount=20 ...and I see the point, as it is a reasonable quality, apparently with only the EXIF field for DPI altered, although that should not matter when simply taking a file of a certain number of pixels and displaying it on the web on our monitors. Hmm...gotta read more of that thread before I comment.

OK, read the rest of the thread, and I can't say that I have internalized the 'procedural error' which resulted in the blurry output, but at least this post demonstrates that something can indeed be done procedurally to alter quality -- even though in theory it should not.
https://photography-on-the.net …p?p=12316085&po​stcount=53

frenchconnector wrote in post #12324854
That thread is silly to say the least. DPI is for printing only and obviously has no effect on pixel dimension of the image. PPI is determined by the physical dimensions of the screen each of us is looking at. Image size in pixels divided by the length of the screen the image occupies equals PPI.

This whole woodoo multiplying, dividing of pixels, saving and resaving images reshaped into blocks (that you think are pixels) do not change anything and just waste your time and confuse others.

This.

René Damkot wrote in post #12327723
This.

Yep...