DPI question

A friend sent me this photo that she is wanting to print on metal. The photo was taken with a cell phone on their farm.

These are the instuctions that were sent to her regarding sizing for printing from the print company she contacted. She sent it to me, I guess because I am the only person she knows that does some photography (novice)
Hi,

Yes, here are the instructions for doing that:
Generally, files sent to us for printing should be 200-300 pixels per inch (ppi) at the desired print size. However, simply looking at the resolution of file size does not indicate any capture-related issues - focus, motion blur, chromatic aberration, or excessive noise/grain.

We recommend evaluating each image individually. In Photoshop, the best way to see a print preview is by following these steps:

1. Open the image file.
2. Click the Image heading at the top of the application window.
3. Click Image Size.
4. In the Image Size dialog, check the Resample Image box.
5. For Document Size, enter the desired print size.
6. For the Resolution, enter 300 pixels per inch.
7. Click OK.

You now want to get the ruler in Photoshop to match as closely as possible to a real inch so you can see the print size.

8. Turn on rulers in the view options in Photoshop and compare the onscreen ruler with an actual ruler.
9. Once the correct zoom factor (Example 30% zoom) is found, it will work for all files viewed on that monitor.

This will approximate the print size. If the print size is larger than your monitor, you will need to use the hand tool to click and drag in order to view the entire image file.

If you would like a second opinion on the quality of your image files, you can include instructions when submitting an order through Bay ROES requesting that we evaluate them prior to production.

I also attached the file in question

Thanks for any insights

duckster wrote in post #19084665
A friend sent me this photo that she is wanting to print on metal. The photo was taken with a cell phone on their farm.

These are the instuctions that were sent to her regarding sizing for printing from the print company she contacted. She sent it to me, I guess because I am the only person she knows that does some photography (novice)
Hi,

Yes, here are the instructions for doing that:
Generally, files sent to us for printing should be 200-300 pixels per inch (ppi) at the desired print size. However, simply looking at the resolution of file size does not indicate any capture-related issues - focus, motion blur, chromatic aberration, or excessive noise/grain.

We recommend evaluating each image individually. In Photoshop, the best way to see a print preview is by following these steps:

1. Open the image file.
2. Click the Image heading at the top of the application window.
3. Click Image Size.
4. In the Image Size dialog, check the Resample Image box.
5. For Document Size, enter the desired print size.
6. For the Resolution, enter 300 pixels per inch.
7. Click OK.

You now want to get the ruler in Photoshop to match as closely as possible to a real inch so you can see the print size.

8. Turn on rulers in the view options in Photoshop and compare the onscreen ruler with an actual ruler.
9. Once the correct zoom factor (Example 30% zoom) is found, it will work for all files viewed on that monitor.

This will approximate the print size. If the print size is larger than your monitor, you will need to use the hand tool to click and drag in order to view the entire image file.

If you would like a second opinion on the quality of your image files, you can include instructions when submitting an order through Bay ROES requesting that we evaluate them prior to production.

I also attached the file in question

Thanks for any insights

Hosted photo: posted by duckster in
./showthread.php?p=190​84665&i=i24401124
forum: RAW, Post Processing & Printing

So, what's the question?

What size print are they wanting and what size is the original?

Sorry, I probably was not clear

She wants to print at 20x30 or even 24x36 if she can.

The curent photo is 2592 x 1944 and the print company had suggested that it needed to be 300 dpi. I didn't know how to convert

Thanks.

At 20x30 it would need to be 6000×9000 pixels. The file as it currently sits would be roughly 8.5 x 6.5. Now 300ppi is for optimum quality but good results can be hard at less than that.

a 20" x 30" final print at 300 ppi means you need to provide a file

1. 20" *300 pixels in the short direction, and 30" *300 pixels in the long direction... 6000 x 9000 pixels.
   
   So you resize the pixel count from the original 2592 x 1944 by (6000 pixels / 1944) = 3.1x to get that size file
   [Depending upon the program used, you can simply tell it to output a file which is 20" x 30" print, at 300 pixels/inch
   (some programs may mislead users by calling it 'DPI', but it really 'ppi'!)...enter '300' in any event for 300 pixels per inch of print
   
2. To get 24" x 36" at 300 ppi, the arithmetic is 24" * 300, and 36" * 300, or a file which is 7200 pixels x 10800 pixels.

1. 20*200 by 30*200
   
2. or 24*200 by 36*200
   

Thanks for the information. I have only done small prints in the past and never a print on metal, which is what she is wanting to do with this photo. It is of their own little ranchette with their sheep. So it appears that would not have enough pixels for a print that large, if I am understanding correctly.

So using those numbers and 200 dpi, it would appear that she would be OK with 8x10 but probably not larger?

duckster wrote in post #19084799
Thanks for the information. I have only done small prints in the past and never a print on metal, which is what she is wanting to do with this photo. It is of their own little ranchette with their sheep. So it appears that would not have enough pixels for a print that large, if I am understanding correctly.

So using those numbers and 200 dpi, it would appear that she would be OK with 8x10 but probably not larger?

You can upres the photo in photoshop and there is no reason you cant get a decent 16x20 out of it. Artifacts might start to show at 20x30

Go ahead and resize the image to the dimensions others have told you, don't worry about dpi since you will just enter the pixel dimensions directly of 9000x6000.

Then view the image at about 70% zoom level and see how it looks. If it looks bad there it won't look great in a metal print. Keep trying smaller sizes from the original until it looks good.

TeamSpeed wrote in post #19084811
Go ahead and resize the image to the dimensions others have told you, don't worry about dpi since you will just enter the pixel dimensions directly of 9000x6000.

Then view the image at about 70% zoom level and see how it looks. If it looks bad there it won't look great in a metal print. Keep trying smaller sizes from the original until it looks good.

^^^
Resize the image! I resized a Canon S110 image to make a 12" x 60" canvas wrap. I did the same 12" x 60 canvas with another scene shot by 7DII. Can I tell a difference in print quality if I did not KNOW which camera shot which photo?! Not really.

Now that brings up another question. I have never resized an image.

Can it only be done in Photoshop? I use Apple Photos for all of my (limited) post-processing work

So she sent me what is apparently the original and it is 9000x6750 when I load it into Photos.

That should be plenty to print?

duckster wrote in post #19084822
So she sent me what is apparently the original and it is 9000x6750 when I load it into Photos.

That should be plenty to print?

It gets a 30" x 22.5" print at 300 ppi...ask for a 20" standard print height and the lab will cut off a somewhat arbitrary portion of the top or bottom (or a bit of both) of the original image unless YOU decide and trim off the least important 750 pixels from top/bottom/bit of both.

Photoshop and most other postprocessing programs that handle photos has a Resize function.

Which phone has a 61mpx camera that coincidentally has the exact needed dimension on one side? That was fortuitous.

duckster wrote in post #19084721
Sorry, I probably was not clear

She wants to print at 20x30 or even 24x36 if she can.

The curent photo is 2592 x 1944 and the print company had suggested that it needed to be 300 dpi. I didn't know how to convert

Thanks.

Check out links below.

Website claims print ppi is determined by viewing distance.

http://www.photokaboom​.com …size_viewing_di​stance.htm

.... and this link gives 2 calculators at bottom of page.

http://www.photokaboom​.com …rinting/1_calcu​lators.htm

According to their calculator, you can get an acceptable 20 x 30 at 86 ppi.
... and ppi of 72 would allow for the 24" x 36".