X Pixels Equals How Many Inches??

[mtbbrian]

I am sure this or something like it has been asked before, but here go...
I want to know how how to figure out what pixels convert over to inches.
I have looked unsucessfully!
Thanks!
Brian

[Trevor Ash]

You can't really do that in most cases. Unlike "Inches" pixels aren't a constant value across different mediums.

Here's proof:
When you set your monitor to 600x800 how big will a 400x400 image look on it compared to a monitor that is set to 1280x1024? Answer: If you took a ruler and measured your screen you'd find that image displayed on the 1280x1024 would be smaller. Same amount of pixels, but more pixels per inch makes it look smaller.

If you have a need to convert pixels to inches then you simply need to know how many pixels the device will output per inch (for printers and monitors this is configurable)

Maybe I'm not understanding your question.

[another view]

Yes - a pixel isn't a specific dimension. It only turns into a specific dimension when it's printed. On a print, they should be small enough that they can't be individually seen. However, the pixels used to make billboards are very large (low resolution is all that's needed when the viewing distance is 100' or more).

With most prints, there's the old rule about 300dpi which may or may not be necessary - depends on a lot of factors.

[mtbbrian]

Basically, I was wondering if a file that is about 5700x2600 pixels will print out well to about 9"x12".
It was scanned at 1200dpi.
Brian

[Trevor Ash]

Oh, okay. Let's do the path. If you want to print a 5700x2600 image at 9x12 inches then 5700 divided by 12 = 475 pixels per inch needed for the long side and 2600 divided by 9 = 288 pixels needed for the short side.

Obviously, because we have two different PPI values the ratio of your image isn't the same as 9x12. That means you have to make a decision on how to crop, etc.

Printing your image at 475 dpi will get you a final print that is roughly 5 1/2 x 12.

Printing your image at 300 dpi will get you a final print that is roughly 8 1/2 x 19

Follow?

Also, scanning resolution has nothing to do with print resolution. Scanning resolution is all about translating what your scanning into pixels. The higher the scan resolution the more pixels you'll get. We all know that more pixels will grant you a bigger potential print when you get to that point. That's the only relationship between scanning and printing sizes.

[mtbbrian]

Ahh Trevor?
You lost at the first sentence..
This whole thing is kind of confusing to me.
Brian

;)

[another view]

OK - I'll give it a shot.

The proportion of the picture isn't 9x12 so you'll have to crop the sides (left, right or both) to get it there. With the resolution you've got, you will be able to crop to this size and still have enough pixels left to make a good 9x12 print. If you're using Photoshop, you can set the crop tool to 9 inches x 12 inches at a resolution of 300 dpi. That may end up interpolating (adding pixels) a little bit but you'll still be fine.

You know how printing a full 35mm negative will get you an 8x12, but if you do an 8x10 you loose a little bit on the ends (total of 2") - this is the same concept. Does this help?

[mtbbrian]

Since you put it that way...
I think I finally get it!
;)
What I did was uploaded a file to my local lab, from a negative that I scanned at home.
In the instructions I told them no cropping. I also talked to them about it too. So even it isn't exactly 9x12 I guess that will be OK...
This is the photograph I am talking about...
I submitted it and two others to a "Bike Art" exhibit and got it in!
Thanks Trevor and Steve for trying to explain this to me?!?
Brian

[another view]

OK, another idea. In the first shot, I sized this image to 570x260 pixels which is the same proportion but 1/10 the size so it can be posted here. It's a long skinny image, sort of a panoramic shot.

In the second image, I turned the "constrain proportions" off in Photoshop so I could show you what it would look like if you stretched this same shot to fit the 9x12 proportions.

In the third image, I turned back on "constrain proportions" and gave it the 9x12 proportions you're looking for; and cropped it from the left. Looking at the first and third shots, see how much you lose on the left?

[mtbbrian]

That's a lot you loose!?

[Trevor Ash]

It sounds like you get it now, cool!

You will definetely lose a lot, which was why I said you'll need to make some cropping decisions.

The alternative (if you don't want to crop anything) is to print as large as you can. It sounds like the largest the lab can print is 12 inches. So let them print it that way, they won't crop, you'll get an awesome photo that ends up being 5.5 x 12 and everyone's happy! Sure, it's not 9x12, but Steve already showed you the kind of cropping you'd have to do if you wanted to print it to those proportions.

Does this add anything to the thread or am I making it worse?!?

[mtbbrian]

Does this add anything to the thread or am I making it worse?!?

I'll let you know when I get the print back.
Thanks Trevor.
I think..... ;)
Brian

[mtbbrian]

To recap...
I uploaded a file recently to my local lab for printing.
The file was 5719x2681 pixles.
I wanted it printed to 9"x12" on an 11"x14" piece of paper.
I told them NOT to crop it.
I got the print back today, and the results were a print that was 5 3/4" x 12" on 11"x14".
It looks really good.
Brian

[another view]

Glad it worked out, but it may have been easier and less confusing to tell the lab to print it 12" long, and let the height work out to whatever it is.

Cool shot, BTW - it's a great idea. Good luck with the exhibit!

[Trevor Ash]

Glad it worked out, but it may have been easier and less confusing to tell the lab to print it 12" long, and let the height work out to whatever it is.

Cool shot, BTW - it's a great idea. Good luck with the exhibit!

You know, after all that blabbing of mine I also forgot to tell you what a great photo you have here! I think it's a one of a kind and very pleasing.

[mtbbrian]

You know, after all that blabbing of mine I also forgot to tell you what a great photo you have here! I think it's a one of a kind and very pleasing.

LOL Trevor!
Thanks though!
I appreciate you saying that!
Even if it is, well now!
;)
Thanks for comments on my question.
Brian