Author Topic: Interpolation auto vs...?  (Read 805 times)

mujabad

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Interpolation auto vs...?
« on: January 02, 2018, 10:55:51 am »
Hello again,
Another question here.
If you export (to disk), what is your setting on "Interpolation"? 1. Without any resizing/resampling 2. With downsizing the image (downsampling?), 3. With upsizing the image (upsampling?).
All to increase image quality.
Do you use:
Auto?
Average?
Bicubic?
Bicubi Sharper?
Bilinear?
Can you also tell me, why you use these settings like you do?
Thank you very much!

MikeFromMesa

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Re: Interpolation auto vs...?
« Reply #1 on: January 02, 2018, 02:06:09 pm »
I had the same question so, some time ago, I went through all the settings with an image I was going to resize and then compared them. I could not see much difference between them so I left it on Auto, which is what I use now.

However I was not resizing an image to a large image but only resizing cropped images to their original image size so perhaps if you do resizing trying to double or triple an image size the setting makes a big difference. Personally I would like to know what other people do, and why.


mujabad

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Re: Interpolation auto vs...?
« Reply #2 on: January 02, 2018, 04:51:51 pm »
Thnxs MikeFromMesa.
Bicubic seems to be very popular. Don't know (yet) why. And what if I do not down- or upsize anything? Just want the best IQ?
Hopefully some will join here to share personal experiences (in simple language please;-) )

Bencsi

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Re: Interpolation auto vs...?
« Reply #3 on: January 02, 2018, 08:37:48 pm »
 Just briefly, the interpolation is a kind of recalculation all pixels of new size image from the available pixels. There are several algorithm to make the reduced pixels to match the same visual impression. It is a kind of compression algorithm. In my practice the Bicubic sharper give the best image quality. Of course, there are cases, when the sharpening makes worse result ( e.g. high noise images, dirty sensor/lens made images, too small original resolution images, etc.).
The blowup of images during export also a kind of resampling. PL is not particularly designed for such role, the more than 2x magnification certainly will unwanted shades. If such task is frequent in your workflow, try Photozoom ( http://www.benvista.com/photozoompro )

 What I can propose to you, after the export processing finished, take time to check each exported image quality. If something wrong, go back and correct it. If the sharpening is too much, reduce in the main working area and the interpolation too.

Endre
Win7/64 PC, i7-3770, 3.9GHz, 24G RAM, Intel HD-4000 GPU, 27" calibrated LG monitor 1920*1080 px res. 82 DPI

mujabad

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Re: Interpolation auto vs...?
« Reply #4 on: January 02, 2018, 08:54:32 pm »
Well thank you very much Bencsi!
You're linking to Dutch language (benvista.com)...and that's my language!
I see, their European headoffice is in The Netherlands. And originating from USA/Houston?
I'v read a few things about this subject, but it's not easy to understand for me :-).

Can you tell me what the "Automatic" setting does to an image in Photolab??
« Last Edit: January 02, 2018, 09:01:34 pm by mujabad »

Bencsi

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Re: Interpolation auto vs...?
« Reply #5 on: January 03, 2018, 02:06:03 pm »
As far as I know, PL makes decision about the image content, e.g. nose level, size in pixel, probably the used color numbers within the image. I made now a set of test. If you give an e-mail address, I can send the content for you. The file size is bigger only in case of Bicubic sharper interpolation, all others are same in bytes. The test made on a cropped 1077x718px part from a 7360*4912px image.

Conclusion: the more noise image in Auto interpolation mode choose the Bilinear version, meanwhile on a ISO 100 image the Average. The Bicubic interpolation has no advantage on ISO 2800 image, meanwhile on ISO 100 image has worse sharpness, than Average. Finally the Bicubic sharpen interpolation gives a crystal clear image on the ISO 100 image and makes some artifact on the high noise images. Of course, the bigger pixel number size image has less comparable difference.

It seems, we can not escape from the final image checking of each exported images.

Endre
Win7/64 PC, i7-3770, 3.9GHz, 24G RAM, Intel HD-4000 GPU, 27" calibrated LG monitor 1920*1080 px res. 82 DPI

mujabad

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Re: Interpolation auto vs...?
« Reply #6 on: January 03, 2018, 02:51:23 pm »
Hello Endre/Bencsi. I've sent you a pm.
Thank you very much!

Pieloe

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Re: Interpolation auto vs...?
« Reply #7 on: January 03, 2018, 03:37:14 pm »
 
Same request Endre.
Many thanks.
 

 

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