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Old Jan 6, 2006, 10:11 PM   #11
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Thank you for all the clarification. I understood the OP to only be asking about the 72 dpi and why his image showed up that way at a given dimension. Then came very good explanations about the actual pixels. I understand this too.

When he says he "changes" it to 300 dpi....I was trying to explain this relationship that many do not understand....relative to what they see on their screen. Yes #of pixels increases, but these are all still 1" images.....with different dpi

If I have again err'd, please correct me.






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Old Jan 7, 2006, 3:27 AM   #12
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To see a practical demonstration of the above explanations, if you have Photoshop, open an image from your camera and select "print with preview."

You'll see whatever paper size you're using with part of the image (at 72 DPI) spread across it.

See how poor it would look if you printed it without setting your desired print size.
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Old Jan 7, 2006, 3:57 PM   #13
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Now I am forced into the discussion. The monitor resolutions and the size of the screen does make a huge difference on how big the displayed picture will be. If the recorded picture is at 72 pixels per inch and the resolution of the monitor is 800 you get 72 divided by 800is 0.09. My 17 inch monitor measures 12.5 inches. Then 0.09 times 12.5 inches equals 1.125 inches. If I set my monitor to 1260: 72 / 1260= 0.057 x 12.5 = 0.71 inches [for each 72 pixels] .Thus an M image [3264] would be say 32.2 inches horizontally.

Now if you put the picture in a PP problem and set the picture to fit the screen the rulers on the screen will not measure the real world size as the rulers change their inches/inch size.

Is your monitor 12.5 inches horizontally and is your monitor set to 800 or 1260 pixels?

Now that really clears up the problem! {?}

If you resize the image in inches or total pixels or pixels per inch it becomes more thought provoking.

Now interject dots per inch for printing!

For something real world, is it better to resize the image by PPing or let Cannon Easy Print do the resizing? 4" x 6" ?? I have PS E2 and iP5000.

Stan
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Old Jan 7, 2006, 5:28 PM   #14
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While you are correct on your statement Stan, I would assume we all leave our monitors on the same resolution all the time so we are back to it makes no difference.

The DPI only matters to printing.



To make my point open a photo in PS in Image size change the DPI from 72 to 300DPI ,and do not resample ,now save that file under a different name.....Now open the first picture in windows and fax viewer or I imagine any viewer see the size click actual size check what it looks like, now open the one you saved at 300 dpi ...same size right..



And I do the resize in PS so I can make the crop the way I want, not the way photoprint wants
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Old Jan 7, 2006, 5:55 PM   #15
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Wow thanks for the replies.

The reason for my original question was this:


I can take a picture and it saves to file at 3456 x 2304 @ 72 pixels per inch.

I want to print it at a photo lab at 6x4 (10cm x 15cm).

If I crop and resize it, leaving it at 72 dpi, it ends up at 425 x 283. Obviously this is no good for printing.

If I change the resolution when I resize it to 300 ppi, it leaves it at 1772 x 1181 which is fine for a small print.

What I guess I was asking was, why would it save at 72 ppi on an 8.0MP camera? As soon as you resize, the print size is far too small.


You were right. I had dpi and ppi totally confused. I'm all set with that part now. I was thinking ppi but saying dpi. My question now I suppose is, how do I go about altering either camera settings or photoshop settings so when I upload a picture from the camera it automatically has a resolution of 300 ppi instead of 72 ppi?

Thanks again for your replies (and patience :-))

ViS

*edit for spelling*
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Old Jan 8, 2006, 9:20 AM   #16
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You are not going about the resizing correctly and unfortunately I am only familiar with Photoshop but I would think something like this would be similar in all photo editors.

If you open a picture and look at the image size it will say





if you do no more than change the 72dpi to 300 it will say this





Or you can change to 200dpi which makes a pretty good print and you get this size



As you see you can print a 9 X 12 with no interpolation at all, which would enable you to print a print at leasttwice that size.



I think people try to do strange things with photos and that results in poor quality pictures in print or even on the monitor.

For the most part you are better off leaving the photo editor do the work..just tell it what you want.

Whatever editor you are using I am sure the help section would have instructions and if you google for help you will most like likely find a tutorial on about every process you could imagine.

Especially if you use one of the more common editors Paintshop pro...Elements or Photoshop.
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Old Jan 8, 2006, 12:19 PM   #17
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ViS wrote:
Quote:
. My question now I suppose is, how do I go about altering either camera settings or photoshop settings so when I upload a picture from the camera it automatically has a resolution of 300 ppi instead of 72 ppi?

Thanks again for your replies (and patience :-))

ViS
you don't. the camera's resolution is what it is, and you can't set it for 300ppior 72ppi, because those are PRINTER resolution settings. when you set Photoshop's "image size" to 200 or 300ppi, all it's doing is dividing the number of pixels in the image by the dimensions of the print size you select, showing you how big a print you can get at any given image resolution. note that it gives you this in PIXELS per inch, because it's looking at the image file, not the printer settings. if you disable the "constrain proportions"box, the actual file size (your image file) will not change, and you can experiment to see what size prints you can get at various resolution "settings". if you adjust the paper size, it will show how many pixels per inchyou'll get, assuming afixed image file size.

let's make this simple... keep your image from the camera at itsfull resolution if you possibly can, unless you must crop to get the composition you want. don't reduce it just because you want to make a smaller print. set your printer to its highest resolution and leave it there. as long as your printer can produceat least as manyDOTS per inch than your image contains PIXELS per inch, you'll be home free. when you select the print size, the printer will automatically fit the entire image - less any slight cropping necessary to compensate for paper dimension ratios - to the proper paper size. as long as your PHOTO resolution has at least 200 PIXELS - not dots - per inch in each axis at the print sizes you choose, you will get a good print.





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Old Jan 8, 2006, 2:31 PM   #18
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Ok

I have been leaving the "resample image" box ticked, which is where it looks like I'm going wrong. When I was adjusting the document size for printing, the pixel dimensions were also falling dramatically, so I was having to compensate by increasing the resolution number to bring the pixel dimensions back up to a decent amount.

Here are the steps I've been taking:







So if I untick the resample image, and just adjust my document size from there, I won't need to touch anything else (except maybe a little crop / canvas crop) to bring the picture to the correct shape)?

Sorry I'm being such a pain. This is all very new to me :?
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Old Jan 8, 2006, 5:38 PM   #19
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I've nothing further of a technical nature to add here. I am getting a quiet chuckle and nodding in approval from time to time as I read all of this. Nowhere else can you find the patience, and desire to help you, from people knowledgeable and understanding...as you see here. Give yourselves a well deserved pat on the back. I paid good money and invested considerable time and effort in classrooms tohelp me learn the basics of how all this translates, from dpi to resolution to pixel count. To smoothly apply this from cameras to monitors and printers can be confusing. Throw in scanners too and their settings, and it's not hard to believe a lot of people will be overjoyed to find the answers in these posts. Well done, you do the forum proud!Best regards,

KennethD
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Old Jan 8, 2006, 9:33 PM   #20
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You are exactly correct about not resampling ...and a little crop and your all set.


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