The OP appears to have no idea of how image size, PPI and printing work.  So I wish you luck conroy2009

Sorry to be abrupt, but these are user to user forums.  No one has any obligation even to reply to a question, let alone to run errands for other forum users.

jorgebraque wrote:

 

So you end up with a picture (let's say 1000x800px, 72dpi) that looks fine on your screen with 100% zoom. But you don't want to use this picture for a blog or something, you just want to print it. If you print it with 300dpi

You have a fundamental assumption wrong, probably by listening to too many online "rules of thumb"...  Why do you want to "print it with 300dpi"?  What do you feel that will accomplish?

If it has the right size and look on your screen, determine what ppi your screen is (get a ruler out), set your image to that ppi without resampling, and just print it.  There's nothing magic about 300.

If you want it to look more detailed on the printer than on your screen, which is most folks' goal, you're going to have to work with more pixels and prep your image to look good at print size on the screen, which means using something other than 100% zoom (e.g., 33%).

The best way is to think about the pixel count, set the size in inches or whatever units  you use in your country, and let the the ppi fall where it may.  If you want the most detailed possible print, use the most pixels.  If you want a low resolution print that looks just like what you see on the display, use a low pixel count.  That's not evil, just not typical.

-Noel

jorgebraque wrote:

 

Yes you are right. I thought of that. Well i said 300ppi as it prints so small pixels that get unnoticed by eyes. Printing over 125ppi gives pixels smaller than 0.2mm. That is adequate for eyes.

About the zoom level you are also right. I mentioned that before. If photoshop could render "precise" at every random zoom level that could work.

Printing at lower resolutions (eg. 120, 130, 140...) gives your more control of what you see on the screen and what gets printed.

Now you're confusing ppi with dpi, and pixels with printer dots.  (And there's no way to make any sense out of that last sentence in your post.)

When I send a 360ppi image to my Epson printer, the printer does not use just 360 dots per inch, but either 1440 dpi or 2880 dpi.  The image has 360 pixels per inch, not the printer.

You would REALLY benefit from reading that web page, carefully and in its entirety.

jorgebraque wrote:

 

Yes you are right. I thought of that. Well i said 300ppi as it prints so small pixels that get unnoticed by eyes. Printing over 125ppi gives pixels smaller than 0.2mm. That is adequate for eyes.

Adequate, perhaps, in some opinions, but in others certainly not optimal.  I can easily see differences in printed images at differing resolutions up to about 600 ppi.  If the most detailed possible prints are what you want to make (and it's usually what I want), you need that high pixel count and to overkill the resolution.

It doesn't mean you HAVE to upsample an image.  If a less detailed, somewhat fuzzy print is what you want, just print it.  Modern printer drivers generally do a good job with whatever you feed them.  Whether you feel a print is acceptable to you at 125 ppi is of course entirely up to you.

A tacit assumption is sometimes made that the photograph is sufficiently well-captured to print at high resolution.  Sometimes they're not!  I used to print 8 x 10 images from my 1024 x 768 digital camera back in 1997.  You do what you can with what you've got.

-Noel