Help with post processing for poster sized prints

[Mrcurtain]

Anyone have any suggestions, tips, or links for post-processing digital images intended to be printed poster sized? In the next couple of months I'm going to start starting posters from my website.

It's taken me years to learn how to edit photos for publication on the web. Printing posters will use some of the skills, but other things, like degree of sharpening, will be very different.

Unfortunately, I can't run a bunch of samples to perfect the process due to cost and the fact that I'm in Africa and the printing will be done in the US.

Any ideas?

Thanks,
-Adam #2 :-)

[thien]

In contrary to what we may have thought, you should not try to sharpen an image when resizing it for poster size printing or at least avoid the Bicubic Sharpening in Adobe PS like the plague. This option is only valid when you are downsizing not upsizing. You have to take into account that at poster size the viewing distance is quite different and if any attempt for sharpening is not well done, it will look horribly artificial. In fact, upsizing will actually require smoothing instead of sharpening due to the pixelation occurance of the interpolation algorithm. One of the tool that I have found useful for upsizing is S-Spline Pro. I think it is now called PhotoZoom Pro.

[momshu]

I find it difficult to describe these techniques but here is a reference to explore.
Source; Jim DiVitale> Photoshop User columnist.

Image menu> Image size
Turn on resample image
Switch unit of measurement from inches to percent>type 110%

It will take a few passes so create an action with a function key.
example: 5x7 to 18x24 took 12 passes at 10% increases

[OzJohnsons]

Hi Adam,

www.Lizardtech.com/products/gf make an excellent downloadable tool used by many professionals for resizing images without quality loss, called Genuine Fractals. I think it costs around US$50 for the light version and $150 for the "pro", but installs as a PhotoShop plugin, saving images as an .stn fractal image which describes the image mathematically.When using this tool ensure that the all of the re-sizing parameters are the same as the original eg. pixels to pixels or dpi to dpi. the conversion fails if this is not done. An excellent program, in my view worth the investment. A trial version is available.
Mark Johnson (OzJohnsons)

[sekl]

Adam, here is another source for 110% increase. It contains free PS actions as well. http://www.thelightsrightstudio.com
Happy photoshopping