pixel count

[Rick58]

Question,
What is the highest pixel count file required to print the highest quality 8x10.
The lower end is obvious, but at what point is are you just wasting space or even degrading the photo?

 

[ronlane]

Most of the stuff I've seen says to use 300 ppi when printing. Of course that may not be the highest and it could be totally wrong. But it is what I have used some.

 

[Rick58]

Most of the stuff I've seen says to use 300 ppi when printing. Of course that may not be the highest and it could be totally wrong. But it is what I have used some.

Thanks Ron, my camera is set for 300 PPI. I wasn't sure if that was good or bad. I'm also looking for optimal resizing during PP for printing 8x10. I know 1000 or 1024 is about as good as it gets for on the screen. Which leads me to another question. Do the folks here save two files. On the screen viewing and printing?
Bottom line is I'm looking to produce the finest quailty prints my camera is capable of. No sense having a good quailty DSLR and have it set on Cracker Jacks settings.

 

[jaomul]

I think most viewing programs auto display the size. I only ever saved a screen size file when I gave people a set of photos for print and a set to quickly email or upload to book face. I don't think there is a benefit in the smaller size otherwise

 

[WayneF]

Most of the stuff I've seen says to use 300 ppi when printing. Of course that may not be the highest and it could be totally wrong. But it is what I have used some.

Thanks Ron, my camera is set for 300 PPI. I wasn't sure if that was good or bad. I'm also looking for optimal resizing during PP for printing 8x10. I know 1000 or 1024 is about as good as it gets for on the screen. Which leads me to another question. Do the folks here save two files. On the screen viewing and printing?
Bottom line is I'm looking to produce the finest quailty prints my camera is capable of. No sense having a good quailty DSLR and have it set on Cracker Jacks settings.

The camera creates images dimensioned in pixels. Maybe 12 megapixels, or whatever the camera model says it does. The 300 dpi value is just a separate number, like a comment, and is not related in any way to whatever the camera did. That value really no meaning at this point (not until ready to print it). Camera images are dimensioned in pixels. We have to realize the image size is about pixels.

The meaning of printing 8x10 at 300 dpi is (8 inches x 300 dpi) x (10 inches x 300 dpi) = 2400 x 3000 pixels, which is 7+ megapixels. So a 6 megapixel camera image is fairly close (we can print at less than 300 dpi, like maybe 200 dpi), but it has no room left for cropping, whereas a 12 megapixel or lager camera has plenty of pixels for cropping.

The DSLR camera creates images of aspect ratio 3:2, where an 8x10 print is 4:5, so some cropping is necessary to make it fit the paper shape.

These few details are the very most basic and fundamental first things we must know about digital images, to do the most basic things like resize it.

See Image Resize - Cropping, Resampling, Scaling

 

[480sparky]

........my camera is set for 300 PPI........

Where is that setting located at?

 

[Derrel]

How Big Can I Print by Thom Hogan

This might be useful.

 

[KmH]

Ppi and dpi are not the same thing, and the terms are not interchangeable.
Ppi does not apply to images displayed electronically. Ppi only applies when an image is printed.
So ppi is print resolution. Pixel size is electronic display resolution, if the application displaying the image does not re-size it.

For an 8x10 print anything over about 360 ppi yields no improvement in image quality that the human eye can detect.

However, we have to take viewing distance into account. As prints get larger the ppi that yields no improvement in image quality that the human eye can detect gets smaller.

http://helpx.adobe.com/photoshop/kb/advanced-cropping-resizing-resampling-photoshop.htmlImage sizes onscreen and in print
Image sizes onscreen and in print
The size of an image when you view it on the screen is different from the size of an image when you print it. If you understand these differences, then you can develop a better understanding of which settings to change when you resize an image.

Screen size

The screen resolution of your monitor is the number of pixels that your monitor can display. For example, a monitor with a screen resolution of 640 x 480 pixels displays 640 pixels for the width and 480 pixels for the height. There are several different screen resolutions you can use, and the physical size of the monitor screen usually determines the resolutions available. For example, large monitors typically display higher resolutions than small monitors because they have more pixels.
To find out what your screen resolution is, choose Start > Control Panel > Display > Settings. Look at the screen resolution (Windows) or System Preferences > Displays and look in the Resolution list (Mac OS).

Image size onscreen

Images are of a fixed pixel size when they appear on your monitor. Your screen resolution determines how large the image appears onscreen. A monitor set to 640 x 480 pixels displays fewer pixels than a monitor displaying 1024 x 768 pixels. Therefore, each of the pixels on the 640 x 480 pixel monitor is larger than each of the pixels displayed on the 1024 x 768 pixel monitor.
A 100 x 100-pixel image uses about one-sixth of the screen at 640 x 480, but it only takes up about one-tenth of the screen at 1024 x 768. Therefore, the image looks smaller at 1024 x 768 pixels than at 640 x 480 pixels.

Image size in print

The other values used in resizing images, the physical size of the image when printed, and the resolution, aren't used until the image is printed. Then, the physical size of the image, the resolution, and the pixel dimensions determine the amount of data in the image and its print quality. In general, higher resolution images print at a higher quality. See the sections that follow for more information on resolution and physical size in the below sections.

Image Size dialog box

When you use the Image Size dialog box to resize your images (choose Image > Image Size), four aspects of your image can change:

• the Pixel Dimensions: the width and height of the image
• the size of the image when it's open in Photoshop: this value appears next to the Pixel Dimensions area title
• the Document Size: physical size of the image when printed, including a width and height
• the resolution of the image when printed: this value appears in the Document Size area, in pixels per inch or pixels per centimeter.

Photoshop calculates the physical size, resolution, and pixel dimensions of an image as follows:

• Physical size = resolution x pixel dimensions
• Resolution = physical size / pixel dimensions
• Pixel dimensions = physical size / resolution

The Image Size dialog box allows you to resize your images in two ways. You can increase or decrease the amount of data in the image (resampling). Or, you can maintain the same amount of data in the image (resizing without resampling). When you resample, the image quality can degrade to some extent. You could have to do some extra work, such as using the Unsharp Mask filter to sharpen your image, to compensate for the resampling.
Tip: To reset the Image Size dialog box to its original state, press Alt (Windows) or Option (Mac OS). Pressing these keys changes the Cancel button to a Reset button.

 

[JerryLove]

Ppi and dpi are not the same thing, and the terms are not interchangeable.
Ppi does not apply to images displayed electronically. Ppi only applies when an image is printed.
So ppi is print resolution. Pixel size is electronic display resolution, if the application displaying the image does not re-size it.

That's simply not at all accurate. PPI (alt PPCM) is a common term for pixel density on displays (List of displays by pixel density - Wikipedia, the free encyclopedia). Though they likely shouldn't ("pixel" = "picture element", and that's rather equivocal-able for a screen.)

Confusingly: a displayed image (on a given device at a given zoom) could also be said to have a PPI which is separate from (but no higher than) that of the display.

When it comes to print: DPI is the same as the first PPI above. It's literally the number of dots in an inch. PPI is the number (again: separate from but no higher than DPI) picture elements in the same inch.

Say I have a picture that's 4 pixels high and 4 pixels wide (a 16pixel sensor). Say I print that at 4" x 4". My PPI is 1. My DPI can still be anything (though if it's less than 1 I have a problem). So let's say my dpi was 100. That means each picture element (which is 1"x1") will contain 10,000 identical blobs of ink in a 100x100 array.

For an 8x10 print anything over about 360 ppi yields no improvement in image quality that the human eye can detect.

Assuming that there's no limitation from the medium that sets a max useful resolution (such as ink-bleed in paper), the quality an eye can detect is in pixels per AoV. When translated to PPI, that's not related to the size of the print, but rather related to the likely viewing distance.

I giant billboard seen from 1000' has a different max eye-resolvable resolution than the same billboard seen from 5'

 

[Robin Usagani]

for DSLR (usually 3:2), you need to be shooting 8x12 and then crop. So basically you need (8x300)x(12x300)=8.64 megapixel camera.

 

[Rick58]

........my camera is set for 300 PPI........

Where is that setting located at?

It's right next to the spin cycle setting of course
My error. In trying to get my head round this pixel / ppi stuff, I knew I saw it, but of course it's in the processing software

 

[Rick58]

Wow folks, Thanks for all the info. I thought I would get one response consisting of one sentence. I figured this was a cut 'n dry question.
Bottom line, From what I rather, I saved my 8x10 photo at 411 PPI. That should give me all that I can expect out of a given image on a good quality print.

 

[Robin Usagani]

You should save it at whatever native pixel is after you crop it. I would not resize anything.

 

[Rick58]

Thanks Robin. That's exactly we I did. I cropped down to 8x10. Image information was 411.xx ppi, and I called it a day.

 

[KmH]

Ppi and dpi are not the same thing, and the terms are not interchangeable.
Ppi does not apply to images displayed electronically. Ppi only applies when an image is printed.
So ppi is print resolution. Pixel size is electronic display resolution, if the application displaying the image does not re-size it.

That's simply not at all accurate.

It was accurate in reference to the OP's query - the size of digital photographs and how many pixels were needed for a quality print.
Another poster was using the term dpi inaccurately in reference to digital photograph size

Sorry I did not make that more clear.