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Post by BuckSkin on Apr 1, 2018 0:47:49 GMT
When using Laczos 3 (spelling?) to enlarge jpegs, from approximately 530-px long-side to 1250-px, is it beneficial to do this in three incremental stages, or better to do it in one fell swoop ?
Thanks for reading and all help is appreciated.
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Post by Bailey on Apr 1, 2018 1:12:08 GMT
Hi BuckSkin,
Every time you enlarge an image you are adding new pixels and recalculating the rgb values of the original pixels using interpolation. Each enlargement consequently reduces the quality of the image. Whether the reduction in quality is noticeable or not will depend on the contents of the image and the size of the enlargement.
To minimise the reduction in quality the general rule of thumb is to enlarge in 10% increments. My recommendation is to always enlarge with the smallest increment that's practicle with the time you have to enlarge the image to the target size.
One option you could take (if pressed for time, or even if you are not) is to try enlarging in one go. If the quality of the enlarged image is ok for the purpose of the enlargement, then great. If it isn't, you will have to enlarge in smaller increments as described above.
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Post by BuckSkin on Apr 1, 2018 3:42:21 GMT
Hi BuckSkin, Every time you enlarge an image you are adding new pixels and recalculating the rgb values of the original pixels using interpolation. Each enlargement consequently reduces the quality of the image. Whether the reduction in quality is noticeable or not will depend on the contents of the image and the size of the enlargement. To minimise the reduction in quality the general rule of thumb is to enlarge in 10% increments. My recommendation is to always enlarge with the smallest increment that's practicle with the time you have to enlarge the image to the target size. One option you could take (if pressed for time, or even if you are not) is to try enlarging in one go. If the quality of the enlarged image is ok for the purpose of the enlargement, then great. If it isn't, you will have to enlarge in smaller increments as described above. So increments are better than one big dose; thanks for your response. Would it be better to do any editing/enhancing before upsizing or after ? |
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Post by fotofrank on Apr 1, 2018 5:18:59 GMT
Hi Buckskin,
You are looking to more than double the size of your image. What program are you using that has Lanczos 3? That type of resizing will provide a sharper image, however it creates a lot of artifacts.
I have used ON1 resize to go from a 4X5 to an 11x14 with very good results, doing it all at once.
With that small of an image, I might consider printing it as is and then taking a picture of it and then work on that picture.
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Post by BuckSkin on Apr 1, 2018 5:41:37 GMT
Hi Buckskin, What program are you using that has Lanczos 3? Two or three of our many programs have Lanczos 3 (and Lanczos 2); the one I use most is good old FastStone. I hadn't thought of printing and then photographing; done right, that should yield an image with plenty of pixels. What I am doing is not vital to the scheme of things; I just had some interesting images that would be better if bigger; this is a learning experience for me. I had someone recommend On1 Resize and, for what it costs, it should provide excellent results; when I did a search on resizing, it was recommended in nearly every article as being the best. |
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Post by Sepiana on Apr 1, 2018 5:55:36 GMT
So increments are better than one big dose
Hi BuckSkin,
I also have ON1 Resize; I have it as a module in ON1 Photo RAW. My experience has been the same as Frank's -- doing it all at once and very good results.
I have used ON1 resize to go from a 4X5 to an 11x14 with very good results, doing it all at once.
You can see it in action in . . . www.on1.com/blog/category/product-training/on1-photo-raw-2017-resize/
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Post by Bailey on Apr 1, 2018 6:45:38 GMT
I hadn't thought of printing and then photographing; done right, that should yield an image with plenty of pixels Every printer has its own native printer resolution. Epson = 360ppi, Canon = 300ppi. Your printer will most probably be around 300ppi native resolution. In this case, your long side of 530px will be between 1-2" long. If you choose a larger print size if needed to fill your camera's viewfinder, your printer will enlarge the image to its native resolution internally before printing anyway. So in this case you would be photographing an enlargement. Just be aware that if you don't have a calibrated screen and appropriate printer profile you might have to do additional colour correction after photographing the print because the colours on the print might not match the colours you saw on your screen before printing close enough. I would think enlarging your image digitally in an application will give you better results. Also, bear in mind that any reduction in image quality due to enlarging (if done properly) is less likely to be noticeable if the image is only viewed on a screen. Reduction in quality will much more likely be noticeable on a large print in my experience. |
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Post by Sepiana on Apr 1, 2018 14:43:20 GMT
I had someone recommend On1 Resize and, for what it costs, it should provide excellent results; when I did a search on resizing, it was recommended in nearly every article as being the best. BuckSkin,
I forgot to address this in my previous post.
I believe you were an EV forum member. That's where I first learnt about ON1 Resize. It was highly recommended. I have been using it since then and I would highly recommend it. It is worth every penny!
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Post by Bailey on Apr 1, 2018 23:25:51 GMT
Hi BuckSkin, Every time you enlarge an image you are adding new pixels and recalculating the rgb values of the original pixels using interpolation. Each enlargement consequently reduces the quality of the image. Whether the reduction in quality is noticeable or not will depend on the contents of the image and the size of the enlargement. To minimise the reduction in quality the general rule of thumb is to enlarge in 10% increments. My recommendation is to always enlarge with the smallest increment that's practicle with the time you have to enlarge the image to the target size. One option you could take (if pressed for time, or even if you are not) is to try enlarging in one go. If the quality of the enlarged image is ok for the purpose of the enlargement, then great. If it isn't, you will have to enlarge in smaller increments as described above. So increments are better than one big dose; thanks for your response. Would it be better to do any editing/enhancing before upsizing or after ? I rarely do any upsizing,but I would always first enlarge to the target size with as little as possible reduction in image quality and then use the enlargement as a base to do any editing. Sharpening would be the last process as enlarging tends to soften images. |
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Post by Peterj on Apr 2, 2018 3:01:10 GMT
Common practices aren't always best followed in all cases. I've used resize often - the largest I've tried thus far is 40 x 21 inches with stunning results. My practice using On1 PR2018.1.1 is to open raw file 1) first in develop applying lens correction, setting white &black points, adjusting exposure, reducing luminance and color noise then sharpening 2) selecting the effects module where dynamic contrast, color, and many other options are available 3) last step is to select resize The above steps work perfectly with jpg also I've never resorted to incremental enlarging - never questioned resize results. A short video about On1 Resize |
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Post by Bailey on Apr 2, 2018 3:01:14 GMT
I have used ON1 resize to go from a 4X5 to an 11x14 with very good results, doing it all at once. Hi fotofrank, I have also seen images enlarged by PSE from about 4 x 5 to about double the size with very good results. But these were reasonably high resolution 4 x 5's (400ppi => 1600px X 2000px). It would be interesting to do the same enlargement in ON1 Resize and PSE with a low resolution 4 X 5 (72ppi => 288px X 360px) and compare them. Both the 400ppi and the 72ppi images would print out with a size of 4"x 5". With the lower pixel count in the low res. image, I suspect both ON1 and PSE would have to work a lot harder to get good enlargement results. I don't have ON1, so I can't do the comparison. Just some food for thought  |
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Post by Peterj on Apr 2, 2018 5:08:36 GMT
Here's an example of a Wandering Jew original size = 3334 x 2895 that was upsized 4x with On1 resize. No incremental steps used in resizing. WJ orig size  WJ 4x too large here's a link cloudup.com/cSk0qawElhA |
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Post by Sepiana on Apr 2, 2018 5:29:14 GMT
Common practices aren't always best followed in all cases.
Pete, yes, indeed! I quite agree.
I can confirm it. That has also been my experience with ON1 Resize. |
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Post by Bailey on Apr 2, 2018 5:35:21 GMT
Common practices aren't always best followed in all cases. Yes, I agree as well. In my original post I said:
When I look at the WJ photo in your link at 100% (which is the only way to review an image on screen, especially if its intended for printing), I can see what to me are some artefacts. It would be nice to see if they are there in the original or if they were introduced during the enlargement. |
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Post by hmca on Apr 2, 2018 5:54:12 GMT
Bailey, not sure what the problem is. I took a screenshot of the size in both pixels and inches of Peter's emlargement:   Perhaps you didn't download it or view at full resolution. Edit....I see Bailey deleted his post with his screenshot. |
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