upscaling files for enlargement

I could really use some suggestions on the best way to upscale images for larger prints. I'm doing a few prints for a client, and I would like them to be as sharp as possible. I don't have a lot of experience with this so I would really appreciate some help.

I've read some about sharpening at native res, then upsizing beyond your final print size using the bicubic smoother feature in ps, then sharpening again, then downsizing to the final size using the bicubic sharper method.

Any suggestions here, the images start to look kind of ugly when viewed in PS after all that, and I don't want them to come back looking that way from the printer.

Thanks again for all the help, it's greatly appreciated
Kevin

I use Genuine Fractals 6 from OnOne software
http://www.ononesoftware.com/
MK

Frankly, that method sounds terrible to me, Kevin.
So many unneeded steps that do nothing but damage image pixels.

I would leave the image unsharpened, resample upward one time using Bicubic Smoother to the size you wish to print, and then sharpen accordingly.
You most certainly don't need GF for a relatively minor upsizing.

Genuine Fractals is a safe bet, Kevin. In the meantime, set your final image size and dpi for print in the Image Size dialog. Select BiCubic Smoother and then click OK. I've done upsizing in steps, and in one shot. It doesn't appear to matter; at least I can't detect any difference. Be sure you've set the correct color profile for your output before resizing.

When I resize an image, I make a duplicate of my master file and flatten it. I then resize as needed.

In your example, all the upsizing and downsizing along with the sharpening is destroying data. That explains why the images don't look so good. Genuine Fractals will help a lot.

-P

You also have to have an idea of viewing distance. A larger print tends to have a greater viewing distance. So you would actually sharpen less for a larger print than you would for a smaller print.

Good luck.

Cheers,

Bernie
http://www.flickr.com/photos/berniemonette

I actually find the result of Genuine Fractals to look a bit weird, it's a very cool concept, but.. IMO the results are not organic. I use a simple method that may sound counter intuitive, but the prints look great.. this is for 20x30in prints from anything like a 20D to a 5D mkII. I had two people last week send me an email asking if my 5D prints were 4x5.. !!

1. Flatten image
2. Duplicate base layer, set to "luminosity mode"
3. On the new layer, unsharp mask at min radius and max strength, usually about 3 times, do NOT flatten
4. Upsize with PS's bicubic smoother (for my epson inkjet I go to 360 ppi, always)
5. Adjust opacity on the sharpening layer, and possibly create a mask to only sharpen select regions. Be very careful not to oversharpen. Sometimes I'll make the mask before upsizing, to save on computation time, but always adjust opacity after getting to the final print size.

Note: Most people recommend sharpening after upsizing, in my experience this doesn't matter. Either you upsize sharpening artifacts, or you sharpen upsizing artifacts, in the end, the effect is the same. Might as well sharpen the details that are there, at the finest level that they exist, and after uprezzing back off with the sharpening until you don't see any artifacts. Sharpening before upsizing saves computation time too. What is important is to adjust the amount - opacity - of sharpening specific to your print size... large prints need less.

View your upsized file at 50% to get a good idea for sharpening effect on inkjet papers.

Now... here's a trick that really helps when going really big... like taking a cropped 20D file at high iso to 20x30 (continued from before):

6. create a 50% gray layer in overlay mode
7. add noise using the PS add noise filter: max amount, gaussian, monochrome
8. apply 0.9 radius gaussian blur the noise
9. adjust opacity to taste, consider using a mask (probably the same or similar one as your sharpening mask). For clean files, about 5-8% works well for me in the sky, and 25-35% in detail rich foliage.

This "noise" acts like film grain, and looks very organic compared to the digital artifacts that arise from uprezing, hiding the uglies. Grain, in a print, really is not a bad thing. It just informs the viewer that they've come too close to the print, and that they should take a step back, while retaining the organic look a photograph should have IMO. This works particularly well on a textured fiber or rag paper. This is in contrast to the result of genuine fractals, which IMO adds a level of computer generated look. My method, however, is probably not applicable for truly giant enlargements, like a billboard, where genuine fractals may in fact shine.

Without too much bother, Qimage Pro does all the behind the scenes final print sharpening, optimizing the upsizing for native printer resolution, etc. for the best possible print from your equipment. Typically, large prints that are intended for viewing at a greater distance can (and should) be more aggressively sharpened. Depending on the image, native Photoshop tools like smart sharpen, unsharp mask, high-pass filter masking used on the entire image, or applied to the blue channel (usually the noisiest), or in Lab mode applied to the luminance channel (for sharpening without adding color noise), or third party productions like Photokit's Output Sharpener, and/or FocalBlade - should be in your bag of tricks for sharpening. The trick of applying a small amount of noise is a wonderful technique for certain images - really does look like film. Also, you'll find that a good photofinisher might actually do a bunch of image optimization on his own, so you might not have to do the final output sharpening yourself. I have seen some breathtakingly sharp images taken with a 6.1mp D70 enlarged to 24x36.

Hi Kevin,
I bet you're sorry you asked hey..he,he,he

The best results will come from an originally sharp image, that goes without saying.
If you're using any in-camera tweak for sharpening I suggest you turn it off. I don't use it.

I take the original UN-sharpened 16 bit TIFF & save to 8 bit, and run it for the larger print size using GF..Save to JPEG, then open and sharpen using USM in PS. I zoom to 50% & sharpen until the image just begins to look slightly over-sharp. I use a range of 1 to 1.7 pixel radius, threshold zero, then use the amount slider until it looks right..Usually no more that 170
Save again to JPEG & you're done.

Works for me

Thanks guys for all the information!!

I'm feeling a tad overwhelmed with all the details, I will have to start doing some testing to see what I can figure out. It sounds like the method I was trying isn't the best approach though. I got that off a web based tutorial on printing larger.

What settings do you guys use in the USM filter? I generally have radius at 1.0, threshold at 0, and I sharpen anywhere from 100-180 depending on size.
How can you tell you are truly oversharpening, what are the tell tale signs?

I'm trying to print 20x30 images from my Canon 50d. I have printed this size in the past, or larger, and haven't had any issues, but I want to get the best possible prints I can for this client.

Everyone uses slightly different methods to sharpen for different output formats (as you'll soon see),
but you can't go wrong trying:
Amount-85%
Radius-1
Threshold-4
Whichever way you go, put USM on a separate layer and change the blend mode from 'Normal' to 'Luminosity' . This helps to keep artifacts to a minimum. Using a layer mask on that layer to selectively sharpen the image instead of a global sharpening is often a good idea, too. As Floris mentioned, check it out at 50% for a good idea of how the print will appear.

How can you tell you are truly oversharpening, what are the tell tale signs?

If, at 50%, the sharpening looks "unnatural" - ie. "sharper" than you would expect could be possible in reality, then you've gone too far. Unsharp mask, and any other sharpening method, are basically increasing the contrast around the edges - they are making little halos, if those halos become noticeable (at 50%) then you've gone to far. Better to undersharpen than oversharpen. It takes some practice, so you may want to try some settings on crops of a larger print, and see what the results look like.

Thanks again for all the help guys!!

I'm starting to feel a little more confident about getting something back from the printer that looks right...

It sounds as if there are as many sharpening methods as there are photographers. I'm sure they all work well for their intended uses.

I simply perform normal adjustments in CameraRaw, set the Sharpening to Amount 75, Radius 1.0, Detail 50, choose the largest output size offered in CameraRaw at 300dpi. After saving the output to Photoshop CS4 format, I'll change to 8-bit and SRGB, save as a JPEG, and send it to Mpix for printing. The 30x20 prints I've done this way are stunning.

Hi Kevin, thought I would way in here towards the end because I have a totally different method. I have used this many many times on files from a 10mp Canon Xti for final prints of 24x36 that I would put up against any of the costly time consuming methods fore mentioned.

This is what I do for a 24x36 print, but size doesn't matter all thats needed is a file of 100ppi minimum.
I size the the master file to 24x36 with no interpolation at all, ending up with a file size of 24x36 at 114ppi. Yes only 114ppi. Do not sharpen and then upload to Mpix where it is printed on Kodak Endura Supra VC paper on a Lightjet printer. Done. Spend the rest of your time taking more pictures to sell. Beautiful every time with a guarantee. I'm tellin ya the results are outstanding! Oh yeah a 24x36 will cost ya $45. And no I don't work for Mpix or am affiliated in any way with them, but the results I consistently receive have totally sold me on their quality.

If you start with a high quality file your will end up with a high quality print.

Any way, what ever you chose hope it all turns out well for ya.