Minor uprez question

[Lon Overacker]

I've got a large ~900MB file scanned from 4x5 at 2400ppi, 16bit. The "raw" size of the output is approximately 32x40" at 300dpi output. I typically will work the file in PS CS3 at my print size, which in this case is 20x24"(approx) at 300dpi. I Spent a ton of time in clean up, processing, layers, masking, etc., etc. and have a nice looking file ready to print at that size.

But I f'd up in my matting/framing calculations. Long story short, I've already ordered frames and mats but it turns out I need the short side to be 20.5" and not 20" to have everything work out with the mat/frame.

Question is, if I resize the print to 20.5" width that is obviously uprezing the file and resampling would be checked in the Image size dialogue. Assuming the usual bi-cubic resampling. With such a small dimensional change, do you think the bi-cubic resampling in CS3 will be sufficient going from 20" to 20.5" and still get a quality print? I can't tell the difference at 100% on my monitor, but I expect that doesn't mean a whole lot. What should I look for in terms of image/print degradation?

I really don't care to go back to my raw scan and re-work the entire file, but if you think the quality of the print would significantly suffer because of the uprezing, I guess that's what I'll have to do.

In other words, wouldn't there be a difference between going from 20 > 20.5 vs. 20 > 40? I'm assuming it's almost linear and the larger the uprez, the worse the result. so, only increasing a half inch from a 20" size shouldn't be too bad should it?

Any advice is appreciated.

Lon

[Greg Lockrey]

You ain't going to see it.

[Joanna Carter]

And a little hint for the future:

Scan your film at the higher resolution/size, do all the respotting required and then save that file at the full size. You can now add all the layers and adjustments that you need, in the knowledge that resizing will not have any serious impact on quality. If you need to rework any of the layers or adjustments, you can always remove the previous layers and start from scratch with the already spotted background layer.

Then, if you want smaller copies, resize that image and, if necessary, save the new version under a different name.

[Frank Petronio]

You could always crop an 8x10 section out of the original and up-rezzed files, print those out, and put your mind at ease.

But be careful. Once you start realizing where you can cut corners you'll take the slippery slope to becoming a slob like me.

[Mike1234]

If it were me I would just add a border of whatever color best suits the image. I don't like resizing. That said, as others mentioned, you might not see the degradation in that small change... but pixel interpretation is just that... interpretation... and this will "always" degrade the image at least "somewhat". Make a backup copy of your image before you do any more fiddling.

[Tyler Boley]

I would not resize, particularly that small amount, you are re-writing all the pixel locations. Don't check resample, let the printer driver scale from the native info as needed, I think you will be surprised at how well it does. Besides, 300 was not native in the first place...
Tyler

[Lon Overacker]

Thanks Folks!

Thanks for the "tip" Joanna. I did mention my scan was large and all my originals are scanned at the "large" size and spotted/cleaned up at that large size so I only have to do that once. The "working" file I resize to print size and I didn't anticpate having to print larger than 20" on the short side. Working with layers and such with the 900MB file is excrucuiating with my current setup. Even 500MB is tough, but workable. Anyway, you're right on with the workflow and that's what I usually try and do. Unfortunately, I now need 20.5"

Adding a border? That doesn't solve the problem because around the actual print image, I have a .5" white "reveal" space before the edge of the mat. Sorry I didn't mention that.

Frank, I may very well crop out an 8x10 and print it. In fact I had already cropped a file to 8x10 for printing because I also wanted to see the results since this is from a flatbed scan I've done myself and I want to see how well the 20x24's came out. Now, with the uprezing I have even more of a reason to do an 8x10.

Also, a good idea Tyler about just letting the printer scaling change. I had mentioned 300dpi, but actually it's 304.8dpi for the LJ5000 at Calypso. But I may be having the prints done by WCI and the acceptable printer resolution may be such that I can scale the output resolution down a little and not have to uprez the actual pixels.

good ideas, thanks!
Lon

[Tyler Boley]

Sorry, I had assumed it was inkjet. If you have to resample I doubt there will be a problem.
Tyler

[Ed Richards]

Unless that is a professional flatbed, you are may be wasting your time and computer memory working at 2400 DPI. I use a well tuned consumer flatbed, but I down sample every file to about 1800 DPI, which is the real resolution. (I scan at 4800 for noise reduction, have Vuescan reduce the file to 2400, and go to 1800 in PS using bicubic sharpening.) Cuts the file size in half from the 2400, and the extra size is not really extra resolution. I use Qimage to generate the print files, because it has a great engine for resizing and doing output sharpening. It generates a file that matches the native resolution of the printer so the printer does not have to interpolate. Of course, if you really want to work efficiently, do black and white - cuts down the file size by 2/3s.:-)

[Greg Lockrey]

Unless that is a professional flatbed, you are may be wasting your time and computer memory working at 2400 DPI. I use a well tuned consumer flatbed, but I down sample every file to about 1800 DPI, which is the real resolution. (I scan at 4800 for noise reduction, have Vuescan reduce the file to 2400, and go to 1800 in PS using bicubic sharpening.) Cuts the file size in half from the 2400, and the extra size is not really extra resolution. I use Qimage to generate the print files, because it has a great engine for resizing and doing output sharpening. It generates a file that matches the native resolution of the printer so the printer does not have to interpolate. Of course, if you really want to work efficiently, do black and white - cuts down the file size by 2/3s.:-)

It's my understanding that you can't sharpen b&w, I thought that you needed a green layer for sharpening. I'm with you about Qimage though.