Up-sampling Digital Images

Greetings!

As a istD user I've recently been looking into getting some of my better images printed for framing - ideally 16" x 12" or thereabouts. The trouble is when you consider the pixel resoution of the image and factor in the desired 300dpi printing resolution, it means that 3008 x 2008 out of the camera image will give approx 10" x 6.7" of print.

So I guess some serious up sampling is required!

I've dabbled with resizing (resampling) the image in Photoshop, but was wondering if there is a better way?

Does anyone out there have any pointers on the best way to tackle getting larger prints and minimising the resulting degradation in quality?

Thanks in advance!

John

Make sure you are resampling in Photoshop using the "bicubic" option, which will give you the best results. I have found that A3 prints are perfectly satidfactory from the *istDS. Don't forget that when framed the viewing distance will be much greater than holding an A4 print, so there will not be any visible degradation.

I've tried Genuine Fractals, which is supposed to enable large prints from small files, but, although there is indeed no visible pixellation the results look a little "mushy" to me. Not an effect that I like at all.

John,
There are several ways to upsample.
If you have Photoshop CS, there's a menu buried away - Help / Resize Image. This is pretty good at upsizing. Note that the resolution is mentioned in LPI, not DPI, so read the descriptions

Photoshop CS has newer options for resizing too. "Bicubic Smoother" is available for upsizing. Follow that with a little unsharp mask.

Another possibility is "Genuine Fractals". It's quite expensive, but uses fractal techniques to resize, and reportedly gives very good results.

There are some other products out there (saw a 3mega pixel DSLR image put on the side of an articulated lorry!), but I can't remember the links at the moment.

In all cases, be prepared for a positively massive file size

However, as John pointed out, 3000x2000 pixels still produces some stunning A3, and I have done A2 which just looked superb.

Hope that helps,
Matt

Hi,
If you dont have a dedicated prog to upsize do it in steps, say 10 % at a time for better quality.
Bryan

I cane across an article in which one of the Photoshop beta testers, a commercial photographer out of Chicago, clains that within ACR there's an excellent algorithim for opening the files. I've used it to open *st D files at 22 megapixels!

He claims that this is better than any other upsizing method he's seen, so keep that original RAW file! If you want to make a HUGE print, start out by opening the RAW file at the largest size allowed, and work from that!

The limitation is there are only a few fixed sizes, but as a starting point they can be pretty helpful. If I find the article, I'll post a link.

Guys, thanks for the info!

I've been playing with different photoshop (CS) options quite a bit since reading the postings! I did also try the 10% at a time method, but saw some weird effects, a bit like 'tiling' when zooming right in to see the individual pixels (why would I do such a thing? must be developing an obsession - yikes!)

Arthur, I've never heard of ACR. If you could give me a clue where to look on the web it would be appreciated (most search results took me to radiology related sites, hmmmm...)

Thanks again!

John, ACR stands for Adobe Camera RAW. It's built into the Bridge application that goes along with Photoshop CS2.

It's the Adobe RAW converter, and it think it's one of the best available. It'll recognise PEF Pentx RAW files, and has lots of flexability and control.

Of course, this means you need to shoot RAW, but some of us old film hounds like the idea of a "digital negative". The shot was always the basis, the negative the refinement, and the print the true interpretation.

I guess some of us are control freaks. Beats standing around all day in a toxic darkrooom, using a half a package of paper to get the one good print!

Once you get your digital file the way you want it, you can print it over and over. You have no idea what that means to an old darkroom rat!!

Look here

Arthur,

Doh! I should have realised.... I do use Adobe CS and have the Pentax RAW converter installed - just didn't connect the three letters together.

I became a RAW convert about 6 months ago - even bought some big gig CF cards to prove there was no going back! After cutting my teeth on a K1000 and a darkroom in the spare bedroom years ago, RAW is now where it's at for me!

Thanks again...

I know what you mean. I still have Dektol stains on my fingers from twenty years ago! RAW is the closest thing there is to what we're used to, the cameran takes a slide/negtative and that's your RAW material (pun intended) for the final image!

CHeers,

A. Dent

If you have access to a place that does LightJet printing I would highly recommend that.
It prints images as low as 150 - 200 dpi so there is no up-sampling needed, or at least very minimal.
I print at 16x24" at 150dpi (which is a small up-sample) and the quality is stunning!
Just uncheck the Resample box in Image Size window and type in 150 dpi you'll get a 13.4" x 20" out of the regular camera resolution.
I upsize a little to get 16x24.
Trust me, you'll love the quality of the LightJet prints.
You can read about them here:

http://www.cymbolic.com/products/lightjet5000.html
http://www.digitalab.co.uk/digitalab.html
http://www.carlvolk.com/LightJet.htm

I have used a program called Irfanview (freeware for private use) to upsize images very succesfully. It is an alternative to the Photoshop "bicubic", and other fractal based upsizers, and uses a larger interpolation group of pixels (I can't find how many, just at the moment, but I think bicubic interpolates from 9 pixels, whereas Irfanview interpolates from 16). I don't seem to have it set up at the moment, but you can use it as a plug in to photoshop or as a stand alone viewer.

It can be downloaded from tucows, but there is a link from http://www.irfanview.com.

I'd be interested if anybody else hasa go with this, and can comment on the comparison with the other methods mentioned.