Upsampling question

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photo1a
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p.1 #1 · Upsampling question

I have never upsampled and have a question about the limits of this technique.

I have RAW image from my 5D with the dimensions:

pixels H 3888 W 2592 inches: W 16.2 H 10.8

I cropped this photo for a 8x10 print, to the dimensions:

pixels W 1517 H 1214 inches: W 10 H 8.003

I want to make a larger print of the cropped image. I understand the process of upsampling, but do not know the practical limitations. If I upsample from the crop to get an image for a 16x 20 print, what can I expect for the printed quality of the image? That is, will doubling the size of the image produce a bad image for printing? (I will sent the image to Costco for printing.)

Aug 27, 2008 at 09:18 PM

Bernie
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p.1 #2 · Upsampling question

I often upsample to 24 x 36" and larger from my D70 (6 mp 1.5 crop) using CS3 bicubic. When I have a critical area where there is a lot of detail and/or noise I crop it and print it out on my print at 8x10" or so. With some shots, I may do this for a number of areas. When satisfied, it's ready for the lab.

The practical limitation is up to you. I find that textured surfaces like canvas can hide some sins and allow for pushing the size. My canvases have been mistaken for oil paintings....

Aug 28, 2008 at 03:08 AM

tomm101
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p.1 #3 · Upsampling question

Go back and work with the original, There are artifacts created with up/down sampling, so up sampling a down sampled image will magnify these. You saved the original, right?

Tom

Aug 28, 2008 at 02:13 PM

photo1a
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p.1 #4 · Upsampling question

Thanks for the information.

Yes, I have the original RAW file, and a psd file of the crop.

Aug 28, 2008 at 02:21 PM

Peano
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p.1 #5 · Upsampling question

photo1a wrote:
I have never upsampled and have a question about the limits of this technique.

I have RAW image from my 5D with the dimensions:

pixels H 3888 W 2592 inches: W 16.2 H 10.8

I cropped this photo for a 8x10 print, to the dimensions:

pixels W 1517 H 1214 inches: W 10 H 8.003

I want to make a larger print of the cropped image. I understand the process of upsampling, but do not know the practical limitations. If I upsample from the crop to get an image for a 16x 20 print, what can I expect for the printed quality of the image?

Two questions:

1. The dimensions you give for the raw image -- 3888 x 2592 -- aren't the native dimensions of a 5D image in any image mode. Why is this? (In L mode, the 5D image is 4368 x 2912. In M mode it is 3168 x 2112.)

2. When you cropped the image to 1517 x 1214, did you also resample? Or did you crop without resampling?.

Edited on Aug 28, 2008 at 02:40 PM

Aug 28, 2008 at 02:36 PM

photo1a
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p.1 #6 · Upsampling question

Oh, Oh, my error. I checked the image again and recall that on that particular shot I was using the 40D. (I was using both the 5D and 40D on this trip, going back and forth often between the cameras and lenses.) I guess that explains the native dimensions mistake.

When I cropped the image from the original RAW file, I did not resample. I am happy with the crop printed at 8x10, and now want to go to a larger print.

Aug 28, 2008 at 02:59 PM

Peano
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p.1 #7 · Upsampling question

photo1a wrote:
Oh, Oh, my error. I checked the image again and recall that on that particular shot I was using the 40D. (I was using both the 5D and 40D on this trip, going back and forth often between the cameras and lenses.) I guess that explains the native dimensions mistake.

When I cropped the image from the original RAW file, I did not resample. I am happy with the crop printed at 8x10, and now want to go to a larger print.

OK, that helps. Since you haven't resampled yet, there's no need to go back to the raw file. What I would do is increase the print size of that image to 16x20 and maintain the current resolution of 150 ppi (use bicubic smoother, if you have that option in Photoshop). See how it looks on the screen compared with the original. If there weren't any obvious artifacts, I would go ahead and print it.

Aug 28, 2008 at 03:41 PM

photo1a
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p.1 #8 · Upsampling question

Thanks much for the advice. I do have CS3 Extended, so I can do upres with bicubic smoother. Here I go....

Aug 28, 2008 at 04:33 PM

mike young
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p.1 #9 · Upsampling question

A question for a new guy. When I crop to a size in cs3 I just set the dimensions and then crop. How do you determine if a resample is done or not. I know about the resample in image size but not when cropping.

Aug 28, 2008 at 11:35 PM

davekone
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p.1 #10 · Upsampling question

photo1a wrote:
Thanks much for the advice. I do have CS3 Extended, so I can do upres with bicubic smoother. Here I go....

If you are PC based grab a trial version of Qimage and let it do the work. I am a long time user of this printing program and it does wonderful enlarging and down sampling images. Its final print sharpening is superb.

Aug 28, 2008 at 11:41 PM

photo1a
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p.1 #11 · Upsampling question

Thanks for the recommendation re: Qimage. I have read a little about it in in FM. I'll give it a try. BTW, I just got my uprez photo back. It came out very nice.

Aug 29, 2008 at 12:15 AM

SoundHound
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p.1 #12 · Upsampling question

I use PS' bicubic SHARPER to double image size. But Genuine Fractals 5 seems to be better way above 2x and also offers other tools for convenience.

Aug 29, 2008 at 03:20 PM


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