Adding pixels to enlarge image for printing?

[Dagwood]

Forgive the title but I'm searching for a method I saw a year or so back ,possibly in DCMag forum, where you enlarge the image for a large print by adding(interpolating?) pixels. I tried it with success getting an excellent 16x12 print from an initial c.4.5Mp image. Can anyone advise on the name of the method and/or give a link to a tutorial or instruction plse?
Many thanks
Dagwood

Hi Dagwood, (Not sure as bold type may be named differently in various programs, but on mine.)

From the Edit scroll down box you should usually find Edit / Image Size where you can change pixel count and image size. I usually uncheck (tick off)the Resample image box (which isolates the image 's measurements from changing for the moment), alter the Resolution pixel number as desired, re check the Resample image box (tick on); Then set the image size you desire with Constrain Proportion still in check (ticked on) mode, so that the image does not alter from its original proportions.

You may also have Bicubic, Bicubic sharper and softer options etc., available to you as well.

[Dagwood]

Many thanks Andy, that worked a treat and I had some seperate advice about "making sure I used Bicubic Smoother" so will try with and without for printing.
Dagwood

[AndyStevens]

Dagwood, Bicubic Smoother should be better for upsizing - and Bicubic Sharper for downsizing.