OK, PRELIMINARY TEST RESULTS:
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Test-1A: I created a new image 5cm X 5cm at 100px/cm, then I printed and measured it.
Result-1A: It printed out 5cm X 5cm
Test-1B: I created a new Image 5cm X 5cm at 300px/cm, then I printed and measured it.
Result-1B: It printed out 5cm X 5cm.
Test-1C: I created the same Image 5cm X 5cm at both 100 and 300 px/cm, but set the resolution first, then set the sizes in cm's then changed the selection to pixels
Result-1C: Still printed 5cm X 5cm
Analysis-1A,B,C: When creating a new image you can enter in the appropriate sizes in either inches or cm's and set the resolution to be whatever you want, and it will always print out the same size as you inputted, and it doesn't matter what order you input the data.
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Test-2A: I took a picture 500px X 500px that was already set to 100px/cm then copied in and put it into a new document but cranked the resolution up to 300 DPI, then printed it,then noted the size (6/8 inch). Then I took the same picture copied it, and put it into another new document but cranked the resolution up to 600 DPI, then printed it, and the picture was half the size (3/8 inch).
Analysis-2A: You can't add resolution to pre-made pictures, you can only reduce the resolution.
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So you don't need to use that formula usless you want to find out the resolution that a pre-made picture will print at.
Example of this:
I have a 500px X 500px photograph and I want it to print out at 2.5 inches X 2.5 inches. What is the resolution that I should use to acheive this?
Formula:
PRINT SIZE X RESOLUTION = PIXEL SIZE
reverse the formula though to read as follows:
PIXEL SIZE DIVIDED BY PRINT SIZE = RESOLUTION
Therefore:
500px / 2.5 inches = 200 DPI
If I didn't know about using the formula, and decided to crank the images resolution up to 400 DPI, then when I print the picture out it is only going to be 1.25 inches. And then I start tearing my hair out b/c the damn thing won't print at the correct size.
I will re-write some of my FAQ, to support my findings, and then would like you,
and the other members here to review it again, and tell me what you think. Also
please rate it on the scale of 1-10, and the bottom of the FAQ, as well as the other one about Tutorial sites.
Thanks Funkymonk for catching my error!
"Quest for the Cup - 2002!"
"Onto the 2nd round!"