Digi Camera Dpi Conversion – tell me the secret

DD
Posted By
Dave Delaney
Apr 23, 2004
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602
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16
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I have a digital camera which is capable of taking images at 5 million mega px. When ever I take a picture the output res is at 72dpi. I then blow the image up to 300dpi for use in print output work. When I do this I find the image is blurred and becomes fuzzy.

Does anyone have any advice on how I can increase the dpi up but still maintain the quality as much as possible?

Is there a secret rule?
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camera conversion dpi secret

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DD
Dave Delaney
Apr 23, 2004
..
L
LenHewitt
Apr 23, 2004
David,

When ever I take a picture the output res is at 72dpi. <<

Actually it opens with NO resolution information and so Photoshop assumes 72 ppi. You can re-size to 300 (you probably don’t need more than 240ppi for excellent repro) with the re-sample checkbox unchecked and the image data will remain exactly the same, but the dimensions will change.

When you resize WITH the resample checkbox checked you are asking Photoshop to create more pixels. As it has to guess what value those pixels should be, you will loose sharpness, which can be alleviated by using Unsharp mask.
HP
Helen_Polson
Apr 23, 2004
There is no secret rule! With a digital camera you are limited not by the ppi (that’s pixels per inch not dpi) of the final image but the number of pixels your camera produces. What are the dimensions of the image in pixels? And how big (in inches) are you trying to print it? That will help us work out the ppi- if you have an image that’s 3000 pixels square at 300ppi that image will print 10" square.
5MP should produce lots and lots of pixels for you to use- unless you’re upsampling for some reason or aren’t getting a full size print from your camera then you shouldn’t really be having any problems printing to A4 or even A3.
N
norm
Apr 23, 2004
Also make sure that resampling is off when you change the dpi to 300. If resampling is on, you are sampling up.

wrote in message
There is no secret rule! With a digital camera you are limited not by the
ppi (that’s pixels per inch not dpi) of the final image but the number of pixels your camera produces. What are the dimensions of the image in pixels? And how big (in inches) are you trying to print it? That will help us work out the ppi- if you have an image that’s 3000 pixels square at 300ppi that image will print 10" square.
5MP should produce lots and lots of pixels for you to use- unless you’re
upsampling for some reason or aren’t getting a full size print from your camera then you shouldn’t really be having any problems printing to A4 or even A3.
TD
Thee_DarkOverLord
Apr 23, 2004
Tripod
DM
dave_milbut
Apr 23, 2004
what len said. when changing the ppi to 300, UNcheck the resample box.
DD
Dave Delaney
Apr 23, 2004
The problem I was having really was. I’m setting a document up at 300dpi (artwork for the packaging on a box) then when I drag the image I have taken with the camera onto the artwork, it always appears really small because it is at 72dpi. Normally I just stretch the image with the transform command to the relevant size but sometimes the image appears distorted, not by much but sometimes it is noticeable. From what you have all said there isn’t really one particular correct way of doing it. I guess its just gonna be a case of trying all the different methods until I find one that suits.
HP
Helen_Polson
Apr 23, 2004
Dave, you need more pixels 🙂 Try setting your camera to a higher setting (for exmaple mine digital camera has low res, normal and fine modes, plud two pixel sizes). Pick the largest, most high quality setting and see whether that helps.
DD
Dave Delaney
Apr 23, 2004
Ive just tried all the different methods suggested and the one that seams to work the best was un-check the resample option and bump up the dpi to 266. Ok this and then change the overall size percentage to 75% with the resample option checked. You get a slightly smaller picture but it is much clearer and the file size is a touch smaller too.
DD
Dave Delaney
Apr 23, 2004
Helen> Ive got it on to 6 million px with Fine for the setting. Basically it can do any more.
PA
Peter Aitken
Apr 23, 2004
"Dave Delaney" wrote in message
I have a digital camera which is capable of taking images at 5 million
mega px. When ever I take a picture the output res is at 72dpi. I then blow the image up to 300dpi for use in print output work. When I do this I find the image is blurred and becomes fuzzy.
Does anyone have any advice on how I can increase the dpi up but still
maintain the quality as much as possible?
Is there a secret rule?

There’s no need to change the DPI for print work. Simply use the print output settings to get the print size you need.

—
Peter Aitken

Remove the crap from my email address before using.
J
Jim
Apr 23, 2004
"Dave Delaney" wrote in message
Ive just tried all the different methods suggested and the one that seams
to work the best was un-check the resample option and bump up the dpi to 266.

Of course you should not resample the image. All you need to do is to change the output ppi (it is just a scaling factor).

Jim
DM
dave_milbut
Apr 23, 2004
dave, as len said, your original is really resolution independant. it’s coming in as x by y pixels. photoshop is assigning it’s default value of 72ppi to the image. i have to do the same thing with my 3.3 mp olympus. i print to a olympus dye sub who’s max resolution is 306ppi. so i go to image image size, unceck resample (which changes your image) and change the resolution to 306. that way you’re not chaning your picture at all, just the printed representation of it. you’re packing the pixels closer together at 266ppi (or 306ppi, etc) than you are at 72. again 72 is just an arbitrary # that ps assigns as a default. you’re not obligated to use it.

dave
M
mudclown
Apr 24, 2004
First of all, what brand is your camera? Your camera should have a setting to increase the resolution. Chech the manual.
MM
Mac_McDougald
Apr 24, 2004
OP stated that is shooting at 6MP max already.

Seems to be mere misunderstanding of ppi/pixel size/resampling, etc.

Mac
DM
dave_milbut
Apr 24, 2004
some (many?) cameras don’t embed ppi anyway. my olympus doesn’t.

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Give your photos a professional finish with sharpening in Photoshop. Learn to enhance details, create contrast, and prepare your images for print, web, and social media.

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