How do you resize for printing?

I made my first batch of 4x6 prints today. Im happy with the way they turned out but im wondering if there is any optimal way to do it with regards to resizing?
What i did was resize my image without resampling. It ended up being something like 450 ppi. My printer prints at either 600 dpi or 1200 dpi. Is the missmatching figures gonna cause any problems? Or is it better to resample my image to match the printers 600 dpi setting?
Is there any other advice anyone can give me with regards to resizing for printing?
Thanks

You certainly don't need to go as high as 600 or 1200, but I believe it's considered good practice to choose a neat fraction of those. In your case, 300ppi would be perfect.

Damo77 wrote in post #12115068
You certainly don't need to go as high as 600 or 1200, but I believe it's considered good practice to choose a neat fraction of those. In your case, 300ppi would be perfect.

Ya thats what i heard. But in order to get 300ppi, it means i must resample the image. Wouldnt resampling degrade quality slightly? or would printing at an arbitrary ppi like 450ppi be more worse/better than a resample?

Check out this link. This guy tells all about that.
http://www.rideau-info.com/photos/printi​ng.html

boerewors wrote in post #12115147
Ya thats what i heard. But in order to get 300ppi, it means i must resample the image. Wouldnt resampling degrade quality slightly? or would printing at an arbitrary ppi like 450ppi be more worse/better than a resample?

The case for resampling

Either you resample or the printer/lab will resample so it's better that you have control over the process, especially if you like to apply final sharpening.

Just changing the dpi does nothing.

Printers such as Epson/Canon use 360/300 as their ppi (no matter what the printer spec says) or, I believe Epson in some newer printers uses 720.

Labs will typically ask for 300. If you send a 200 or whatever they WILL resample it to 300.

So, what does that mean. If you have an image you want 4 x 6, for example. It should be 1200 x 1800 pixels so that it prints at 300.

8 x 10, 2400 x 3000

To me the question would be "Why? Is it worth the trouble?". You can print a 4x6 or a 5x7 or whatever without bothering with such issues, or if this is for some kind of presentation, sure, resample it to the print size at the appropriate resolution -- it may be 300 ppi or 360 ppi or whatever, it depends on the printer, and then you will want to apply "output sharpening". Like I said, this is all about your intent for the output.

Am i right in saying its better to resize without resampling and then the printer itself will resample the image when it prints?
If thats the case then i think the print labs are unknowingly double resampling.

boerewors wrote in post #12115147
... or would printing at an arbitrary ppi like 450ppi be more worse/better than a resample?

This is essentially the method taught by the last Epson Academy, according to Andrew Rodney:

When using a printer with native resolution of 600dpi, I would resize without resampling to within a range of 150-450 PPI. (For Epson that would be 180-480)

450 PPI might even benefit a smaller print like a 4x6, but no higher. For example, if you resized down to 4x6 without resampling and the PPI value fell at something like 557... you should resample WITH resampling to 450 PPI.

Look at pages 58-62 of this PDF:

http://www.schewephoto​.com …hop/PerfectColo​rPrint.pdf

I agree with using 300 PPI if you don't resize.

Yes, but just changing a 800 x 600 from 72 to 300 still makes it a 800 x 600. Just changing the PPI does nothing.

bohdank wrote in post #12119681
Yes, but just changing a 800 x 600 from 72 to 300 still makes it a 800 x 600. Just changing the PPI does nothing.

Correct, but your printer would still have to scale your image to the chosen paper size. So i was wondering if its better to do in photoshop or let the printer decide. I already came to the conclusion that its better to let the printer decide what it wants to do. But still wondering if there is any difference between the below 2 methods?
1. I resize to the chosen paper size without resampling which ends up with an arbritrary ppi, and then tell the photoshop to print it at actual size. The printer will then figure out what it wants to do to get its 600dpi.
Or..
2. Change the ppi to 300 without resampling and tell the printer to resize / scale the image to fit the chosen paper size

Either way i think will end up with the same result, but im not sure. But i sure beleive its better than resampling to both paper size and 300ppi in photoshop and then printing, because the printer will probably still do some form of resampling before it prints at 600dpi.

If you are printing out of Photoshop to a home/deskjet printer, there is no difference to the two approaches. The software resamples to the native resolution the printer needs.

There are two situations where you can consider actually resampling to a given size and resolution:

First, sharpening is often most effective at a pre-set print size. You can experiment, try resampling an image at, say, 8x10 at 300ppi, then do a sharpen routine while viewing the image in Photoshop at "print size". Then, try sharpening the image without resampling it, by setting the image size in inches and leaving the ppi number alone, and again sharpen while viewing at "Print Size". Print the two and compare.

The other situation where exact size and ppi can matter is with some commercial printers. Some require a minimum resolution/ppi and may reject an image that won't print at a "proper" resolution. Some specifically require a 300ppi resolution. So, for an outside printer you want to be sure you are in touch with their specific requirements, not just for resolution but also for the color space -- some will play well with a wider color space like Adobe RGB, some will require sRGB, while some specialty print places may have other requirements. With Photoshop and your home printer, Photoshop manages colors and is "color space friendly" (making sure you turn your printer managing off and Photoshops on).

I use a local pro lab and had a long discussion with them prior to using them for the first time. As expensive as their equipment is they suggested that I resample using CS since it does a better job then the software that controls their printers. So, if a pro lab tells me their printer software does a mediocre job, I listen.

I have always done my own resizing, when I printed at home and continue to do so.

Some people use Qimage to re-size for printing. I have never used it so do not know if it does a better job than CS5.

When more drastic resampling is required there is Genuine Fractals. I used to use it years ago when I needed large prints from a 5 mpixel P&S and I am amazed at the results that it can produce. I could not objectively see much, if any, difference on a monitor comparing the same resampling to PS/CS but, in print, it was very noticeable.

Whatever works for you.