Image up-sizing

[chauncey]

I've got numerous 22 MP (12.5 x 18.75) images that are stellar @ 200% magnification...
I am also anal retentive about having prints capable of nose-length viewing distance.

What is the best way to up-size that 22 MP image to something in the area of 24 x 36" and
maintain that same print viewing distance?

[tclune]

If you're asking about algorithms, I have found that bicubic splines are as good as anything. I've tried Fourier interpolation, which is supposed to be better according to some, but I can't see any improvement -- and it's much more limited in up-res'ing options -- you need to go up in powers of two on the program that I used. Stay away from pixel replication and linear interpolation. And you really can't do more than double (in each direction. 4x, if you prefer) without noticeably degrading the image. FWIW

[xpatUSA]

I've got numerous 22 MP (12.5 x 18.75) images that are stellar @ 200% magnification

Can you post a 100% crop, say 1500x1000px, from a stellar image in PNG format that was never a JPEG?

200% on your monitor as in zooming in? If so, how does your viewer upsize the image - e.g. nearest neighbor, "smooth", etc.?

...
I am also anal retentive about having prints capable of nose-length viewing distance.

What is the best way to up-size that 22 MP image to something in the area of 24 x 36" and
maintain that same print viewing distance?

I rarely upsize images, but Lanczos2 should give the best acutance for what you seek.

FastStone Viewer offers a very good selection of re-sampling algorithms including Lanczos2 and Lanczos3.

Also see methods compared:

https://clouard.users.greyc.fr/Panth.../index-en.html

http://www.harrisgeospatial.com/Comp...os-kernel.aspx

http://gis.stackexchange.com/questio...patial-context

"bicubic sharper" might be good enough for you, too.

After up-sampling, increasing detail contrast might help. Or wider radius un-sharp mask, or de-convolution sharpening.

[chauncey]

200% via PS CC

[Manfred M]

Any upsampling is going to introduce some softness into the image. After you upsample, sharpen the image at 100% size.

I use Photoshop for 100% of my upsampling, and while the algorithms in some of the older versions were not great, Adobe fixed that issue years ago and I see no difference (when pixel peeping) with what Photoshop CC does versus what OnOne Resize does.

[xpatUSA]

200% via PS CC

I don't use PS CC so that means nothing to me, sorry.

Any chance of a link to a 'stellar image' at 100% or posting a crop here?

[Manfred M]

200% via PS CC

200% is not that much of a "heavy lift" for an enlargement.

[xpatUSA]

I've got numerous 22 MP (12.5 x 18.75) images that are stellar @ 200% magnification...
I am also anal retentive about having prints capable of nose-length viewing distance.

What is the best way to up-size that 22 MP image to something in the area of 24 x 36" and maintain that same print viewing distance?

Printing your 12.5 x 18.75" 300ppi 22MP image at 150ppi would do it. Pixels would be visible by the average human at your viewing distance in either case . . .

[chauncey]

This is part of a photo-merge of a GBH that I made a while ago...took the best parts of several images.
Sharpened in LR only.

[xpatUSA]

This is part of a photo-merge of a GBH that I made a while ago...took the best parts of several images.
Sharpened in LR only.

Sorry, William, neither Elements nor FastStone can open the image on my Win 7 Dell.

[chauncey]

neither Elements nor FastStone can open the image on my Win 7 Dell.

I can't explain that, have uploaded all my images from Photobucket. Ever had trouble before?

[xpatUSA]

I can't explain that, have uploaded all my images from Photobucket. Ever had trouble before?

Me neither; I use the right-click, save image as, in FireFox. Have had no trouble until today with that.

Shopping calls, I'll try again later - more than one way to skin a cat, eh?

[xpatUSA]

I can't explain that, have uploaded all my images from Photobucket. Ever had trouble before?

The file is definitely corrupted. Windows Viewer won't open it. Nothing else will either :C

The GIMP says "Not a JPEG file: starts with 0x3c 0x21" whatever that means . . .

JPEGsnoop says

"JPEGsnoop 1.7.5 by Calvin Hass
http://www.impulseadventure.com/photo/
-------------------------------------

Filename: [C:\Users\Ted\Desktop\basic-GBH-Rising-800-pxle-crop.jpg]
Filesize: [182020] Bytes

Start Offset: 0x00000000
NOTE: File did not start with JPEG marker."

[Shadowman]

William,

Are you printing or a third party? If a third party, do you have freedom to apply specific algorithms or formats?

[chauncey]

It's possible that I uploaded to photobucket without using jpeg.

apply specific algorithms or formats?

don't have a clue.

[dennybeall]

Pops right up and saves to my Win 10 machine fine. Even the one in your last post...

[Stagecoach]

And mine, seems to be a standard .jpg

[xpatUSA]

And mine, seems to be a standard .jpg

And now mine . . for some completely unknown reason.

Ho hum.

[Manfred M]

And now mine . . for some completely unknown reason.

Ho hum.

Technology is a wonderful thing. When it works...

[Shadowman]

It's possible that I uploaded to photobucket without using jpeg.

don't have a clue.

Have you tried upsizing from the RAW image? I've been playing with it and it helps if noise reduction is done in-camera or only needs to be applied moderately.