A

Anonymous

Question

How to view resolution (ppi/dpi) and bit depth of an image

Forum|Forum|14 years ago
March 26, 2012
6 replies
81092 views

Hello,

how can I check the native resolution (ppi/dpi) and bit depth of my image files (jpeg, dng and pef)?

If it is not possible in lighroom, is there a free app for Mac that makes this possible?

Thank you in advance!

How to

Rikk Flohr_Photography

Additionally, you can preview PPI in the Print Module calculated for the Paper Size and printable dimensions:

Rikk Flohr: Adobe Photography Org

I

ilanl81914590

Participant

Definitivamente seria una excelente utilidad para Lightroom, el poder ver los PPI/DPI de cada foto. Especialmente en mi caso, que trabajpo en el area editorial y constantemente hay que negociar entre el tamano para imprimir la foto en un libro y su resolucion. En este momento tengo que asistirme en ese particular con Bridge, pero, repito, deberian incluir esta utilidad en la siguiente actualizacion, o que algun experto desarrollara un plugin.

Per Berntsen

Community Expert

It would definitely be an excellent utility for Lightroom, to be able to see the PPI / DPI of each photo. Especially in my case, I work in the editorial area and constantly have to negotiate between the size to print the photo in a book and its resolution. At this point I have to assist myself in that particular with Bridge, but, I repeat, they should include this utility in the next update, or that some expert develops a plugin.

PPI is meaningless without the pixel dimensions.

LrC does display the pixel dimensions in the Metadata panel, and you can easily figure out at what size an image can be printed at any PPi value.

Pixel dimensions divided by PPi value = Printed dimensions in inches.

A

Anonymous

All you have to do is open any image in Photoshop. Click File > File Info > Camera Data and it should show you Image Size, Resolution, and Orientation. Format (jpeg, raw) can be found under File > File Info > Basic at the very bottom!

A

Anonymous

Thank you for responding so quickly!

The reason for wanting to view bit depth and dpi/ppi in Lr4 is, quite simply, curiosity. I'm new to post processing and I want to learn to understand the effects of specific attributes.

DPI/PPI:

Thanks to your clear and concise explanations, I can forget that attribute for now.

What got me thinking originally was the fact that, according to the Preview app on Mac, RAW-files are 72ppi while JPEGS with identical dimensions from the same camera are 300ppi. This seemed rather odd to me, and still does. I guess it means that by default (based either on default settings of Mac Os or the camera) RAW files are viewed (at 100%, in Mac Os) and printed (if based on dpi) in a larger physical size than JPEGs with identical dimensions.

Bit depth:

I have used several different cameras, which probably have different native bit depths. I assume that Lr converts all RAW files to 16 bits, but the original/native bit depth still affects the quality, right? Therefore, it would be nice to be able to check the native bit depth of an image and e.g. compare it to an image with a different native bit depth.

Checking the native bit depth in Lr would be the most convenient option. Furthermore, I already tried the Preview app, and it reported RAW bit depth as 16 despite the fact that my camera is only 14 bit. Hence Preview doesn't seem to be capable of reporting the native bit depth.

So, do you know if it is possible to view native bit depth in Lr4 or elsewhere?

Thank you in advance!

dj_paige

Legend

Jep Jepjep wrote:
I guess it means that by default (based either on default settings of Mac Os or the camera) RAW files are viewed (at 100%, in Mac Os) and printed (if based on dpi) in a larger physical size than JPEGs with identical dimensions.

It doesn't mean anything like that. The PPI that shows up when the photo moves out of the camera and into some piece of software is completely and totally meaningless. If you are trying to interpret its meaning (as you did above), you will wind up with the wrong conclusion.

Regarding bit depth, Lightroom will show you the camera used for each photo. From there, you should know what bit depth is used. I can't imagine why you'd want to know this, how it fits into any workflow, but there it is.

R

rogerm13077975

Participant

Knowing the bit depth comes into every workflow you will ever do. Checking the bit depth is necessary when you are publishing, receiving photos from various photographers, you will need to check the bit depth. The reason you need to know the bit depth is that your are limited in how far you can push some settings, and filter effects. 8 bit will have problems with color banding in gradients. If LR upscales an 8 bit image into a 16 bit image, you didn't gain anything, although you will find a lot of on-line forums the incorrectly say you do. Some recommend working in a 16 bit work environment with 8bit photos for some advantage. You do get one: Things you add to the image can be added with 16 bit color. Anything you change or adjust will have no advantage. Fortunately, most serious cameras today work in at least a 10 bit color depth. Most are 12 or 14 bits. Fantastic improvement. But, you do need to know if a given file with a 16 bit color bit depth came from 10, 12, or 14. It really gets important if it came from an 8 bit source. It limits how far you can push effects.

I find some answers given here assume we are always going to know our but depths because we know our own cameras. This assumes we are working with our own photos. Many of us work on a lot of photos turned in by hired photographers. We may not know what they used, so we do need to check.

As for native resolution, this does not exist as a dpi/ppi spec. It's simply the frame size. If your camera shoots a frame that is 4096x2045, then that's your native resolution. Dpi is how these pixels are spread across a page, or a screen (ppi) determines the displayed resolution. An earlier post did the math correctly. Do you need to know what it is? Yes, of course you do. If, you're making enlargements, larger than just 8x10, but very large prints. Then, you'll need to know how far you can stretch the resolution.

If you want to find more info online about the significance of bit depth, try searching for info on color banding. It comes up a lot more shooting video than stills, but they go right into the role bit depth plays.

web-weaver

Inspiring

Jep Jepjep,

You ask: "how can I check the native resolution (ppi/dpi) and bit depth of my image files (jpeg, dng and pef)?"

There is no such thing as a native res of an image. An image has a certain pixel dimension, let's say 2000 x 3000.

If you print this at a size of 6.66" x 10" you get a resolution of 300 ppi/dpi . If you print a size of 10" x 15" you get a resolution of 200 ppi/dpi.

That means the resolution in ppi/dpi is the result of the calculation of total pixel dimension divided by desired output size.

Thus ppi/dpi is always dependant on your desired output size and is not "native" to an image.

Native to an image is only the pixel dimension that is determined by your camera's sensor.

dj_paige

Legend

Native resolution is somewhat meaningless, and pointless to check. It doesn't matter what the number is, as it doesn't affect anything you do. When you go to print, then you might want to compute the resolution, but other than that, don't waste your time.

The bit depth of JPGs is always 8, so why do you need to spend time to check that?

The bit depth in Lightroom of RAW and DNG is always 16, so why do you need to spend time to check that?

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