CS6 interpolating D1X file to 24.6MP

[ir0nma1den]

I can't believe my eyes, can someone confirm this?

I just upgraded to CS6, and when I opened up an image shot on my D1X in ACR, I had the option of interpolating to the usual 10.5MP, but I also have the option of interpolating to 17.1MP and 24.6MP.

The file looks flawless to me, how is this possible and why should I not be doing this?

13.3in x 20.5in from a D1X, who would've thought.

[ratpat13]

Your upsampaling your image.

You could always do it in Photoshop in the past once your done processing the raw.

By default ACR choose the native resolution of your file but if you chose one of the two options bellow the raw processor is interpolating to give you more pixels. It's a lossy process (photoshop has to create pixels that never existed) and as to whether its a good or bad thing for you all depends on what your needs are and the final output. If the change in size isn't massive then you might not see much.

If you do need to upscale there is some advantage to upsampaling by one stop in ACR otherwise you can increase the size in photoshop for the final size you need.

So if you need it and ACR is offering a size option that then great otherwise get as close as you can and use photoshop to get you the rest of the way.

[ratpat13]

As to why you might not want to do this is as i said its a lossy process, ACR and photoshop have to create pixels that aren't there which can lead to a softer image and pixel artifices (especially noticeable in areas and along edges with high contrast). But like i said, if it's not a huge upscale and you don't see much in the way of determent to your image and it meets your need then go for it. But if you don't need the increased pixel size for your output then don't, if you need to you can always come back and either output it form ACR at a larger size or do it in photoshop (the difference in which application you use will be small).

[kav]

Some interpolation always exists. It's just much more minor than what you are suggesting. The bayer array doesn't have a full set of rgb pixels, so interpolation exists for two colors on any given pixel and the pixel pitch must be filled in. If you convert via different raw converters, you'll notice slightly different "native" resolutions. These may not be the same as camera processed jpegs. Even Capture One 3 to Capture One 4 changed certain things.

[andrewrodney]

ACR has had settings to upsample past native resolution for years. And yes, it can do a very good job. I find a tad better than using Photoshop. Lightroom provides even more control in terms of how much you can upsample. With proper capture sharpening, this is a good way to upsample IF you know from the raw capture stage you need a larger than native file.

[ir0nma1den]

Thanks for the answer. Since the D1X essentially has native 10MP files, I'll stick to that since I have no reason for upsampling, but it's good to know.

Quick questions, what kind of interpolation should I be using (bicubic, bilinear, etc)? and if I edit in sRGB should I be shooting in sRGB?

Currently I shoot in Adobe RGB since it is a larger color space, but after watching Natalie's dvd, I edit in sRGB.

[ratpat13]

Bicubic Smoother for enlargment.

[andrewrodney]

The color space isn’t a factor here, use Bicubic smoother for up sizing, Bicubic sharper for sizing down. ACR/LR uses an adaptive Bicubic algorithm which not only selects the settings automatically but does this with a more stepless process.