[ms_khw]

I'm getting some photos ready to have sent out for print. I've used the ruler (inches) in PS cs2 to be certain of their size. I've sized them as a 5x7, but looking at them on my monitor they look much smaller than a 5x7. Why is this, are they smaller?

Here is one that is sized according to my rulers in PS ( it's just a wee) bit over a 5x7

[ChuckE]

Inches are unimportant when trying to measure an image on a screen.
I can make this image any size you want by scaling it up or down on the screen, and with the right software I can print this image any size as well, from pinhead size, to as big as a garage door.

What is important is the number of pixels (picture elements - or the dots) in the picture and the quality of image you want as a result.
The image you have here is 505 pixels wide and 360 pixels tall.

With a monitor having a pixel pitch (distance between) of
75 pixels per inch then the image is 6.73" wide and 4.8" tall, at
85 pixels per inch then the image is 5.94" wide and 4.24" tall, at
100 pixels per inch then the image is 5.05" wide and 3.6" tall, at
150 pixels per inch then the image is 3.37" wide and 2.4" tall.

See, it is all relative to the fineness of the pixel size, and there is no one number to go by. I have monitors that are at all these resolutions.

If you are wanting to print, then there again it depends upon at what quality you want for a hardcopy. With this image, to arrive at the size you want, you will need to specify 72 DPI print resolution, which is really a "not too good" for printing (except maybe in some newspapers). Printers generally start at 300 DPI and go up-wards from there with 1200, 2400, even 3600 DPI fairly common.

Your image is not too high in quality, and you will get below average print quality if you try to print this at a 5x7" size. Sorry.

[ms_khw]

Although still confused, but will try to sort through it. As for dpi, my understanding is that you should'nt increase say 72 dpi to say for instance 300. Am I wrong? When I download my photos from my camera- Canon SLR 8mp it does so as 72 dpi. Before sending off to the store to be printed, can I safely change this in PS?

[ms_khw]

Would this be right?
For a 5x7 print:
5" = 25920 pixels at 72 pixels per inch (width)
7" = 36288 at 72 pixels per inch (height)

For a 8x10 print:
8" = 720,000 pixels at 300 pixels per inch
10" = 900,000 at 300 pixels per inch

[ChuckE]

Originally Posted by ms_khw

As for dpi, my understanding is that you should'nt increase say 72 dpi to say for instance 300.

Where did you get that understanding? and what do you think limiting yourself like that is going to do for your print quality?

A DPI setting inside of a picture is only for a printing reference. It has nothing to do with the display on a screen. It also can have nothing to do with printing if you choose to ignore the DPI setting when printing.
(The display on the screen usually - not always - will display at one pixel per screen pixel, unless your application or program shrinks or expands from that.)

To get the 5x7" size printed, just set this image to 72 DPI.
But I am telling you that this printed picture will not be as good as it can be. Send your printer a MUCH larger image, say perhaps over 2000 pixels wide. Use PS to change the DPI setting to result in a 7" output.

I know that PS can change the DPI setting recorded along with the image, but I don't use PS, so I can't tell you how to do so.

If you actually have an 8M pixel digital camera then the images coming out of it are much more 3000 pixels wide and almost 2500 pixels in the other dimension. That much picture data can print fabulous 5x7" pictures, with a setting at about 500 DPI.

[ChuckE]

Originally Posted by ms_khw

Would this be right?
For a 5x7 print:
5" = 25920 pixels at 72 pixels per inch (width)
7" = 36288 at 72 pixels per inch (height)

For a 8x10 print:
8" = 720,000 pixels at 300 pixels per inch
10" = 900,000 at 300 pixels per inch

No. In this instance, you can think of DPI=SPI=PPI.
(Dots Per Inch=Spots Per Inch=Pixels Per Inch
I know I am going to start an argument by saying that.)

If you really want to print at 72 pixels per inch, and you want a 5x7 result, then that is:
(5x72=) 360 by (7x72=) 504 pixels.

That is essentially what you have now. At 72 DPI, it will print the size you want, but it will print poorly.

[wilson44512]

dont make the picture 5x7 before you print. because it wont have good quality. my camera takes pictures at 3072x2304. and when i print them i just tell the printer to print it at 5x7. it gives it better quality.

[Noyb]

Originally Posted by ms_khw

Canon SLR 8mp it does so as 72 dpi. Before sending off to the store to be printed, can I safely change this in PS?

I assume you mean PS = Photoshop ….
Yes ... If you know how … But it’s really not necessary.

Do you still have the original picture before you resized it ??

Attached is an example … assuming your cannon shoots a picture 2200 pixels wide @ 72 DPI

With the original picture in Photoshop .. choose Image Size.
UN-check the Resample Image bullet …
This means that the picture will NOT be changed ... but only the numbers.

Now change the width to 7 inches.

You’ll see that the total pixel width (2200) stayed unchanged …
But the Pictures "default" physical width is now 7 inches …
And the photo will print 314 pixels per inch (when printed at 7 inches wide) … This’ll make a really good print.
Now .. You can use your Photoshop rulers.

With the Resample Image UN-checked .. the Image Size Tool is only a calculator ....
And it only changes the Default DPI in the Image.
It does NOT change or edit the picture.

You want to keep the pictures total pixel size as large as possible for printing purposes.

Is this clearing up your DPI confusion so far ???

[ms_khw]

I'm still confused. And I know-I know my math sucks. I've got this much figured out. If you want a print at 300 ppi than that would be 300x300 = 90,000 ppi Now this is where I get lost for a 5x7 or 8x10 how would I calculate that and place the ppi in my Photoshop image setting?

[ms_khw]

Thanks Noyb, that really does help! And this will give a proper sized image? Now, if I want to change the ppi to 300, I would set this in Image size, and then change the image size to what I want? I was trying to size the photo by using the ppi option.

[Noyb]

PPI does not Change the picture ... if you don't resample .. it just makes the numbers easier to understand.

From here .. I'd use the Canvas Size Tool .... (who's numbers I can now understand) ...
or maybe the Crop Tool for any final Canvas resizing/reframing.

7 inches wide ... at 300 DPI ... is a picture 2100 pixels wide.
The objective is to retain all the pixels you can.

You can change the default DPI (to 300 for example) by resizing ... but why ???
Also .. it's the last thing I'd do ... but only if necessary ... Like downsizing the pictures File Size.

It's the Printer that will give it the desired physical print size ... send him (it) all the pixels you can.
The Printer does NOT care what the DPI is ... only the instructions you give it.

[ms_khw]

Whoops Noyb that confuses me a little. I tried what you said and the photo printed (at 300ppi) as a 5x7 with great quality! thank you so much!

[slipe]

Start with your full sized image.
Select the Crop tool.
Set 7 inches in the width box.
Set 5 inches in the height box.
Leave the resolution box blank.
Crop the image any way you want and hit the Enter key.

Your image is now resized to print at 5 X 7 and all of the pixels you didn’t crop off are being used to make up the image.

You can now go to Image > Image Size to see how much resolution you ended up with, but I guarantee it will be more than enough from an 8Mp camera unless you just crop out a very small portion of the original.

Don’t mess with resolution unless you have to. Use the resolution you end up with after cropping to the proper width to height ratio unless it isn’t enough. I don’t usually resample until I get below around 180 PPI, which is where I can start seeing a difference. Your 5 X 7 will end up over 300 PPI unless you crop off a lot of the image.

[Noyb]

Originally Posted by ms_khw

Whoops Noyb that confuses me a little...

Play with it a while ... You'll get it .. or holler back.
The toughest thing a computer has to do is talk to us Humans in our language or to our visual receptors.
This is what the DPI is for ... Other than that ... It's meaningless ... Crudely stated.

[ms_khw]

I don't completely understand it all, but I will keep working at it as you advise. I can't thank you all enough for trying to help me on this.