Digital experts...Scan images full size vs reduced size.

[rob_x2004]

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Both images come from the same 5400input/400output resolution Minolta 5400II scan. The file is not the size of a football field but it is pretty big. Neither image has been edited or enhanced other than resizing for here.

 

This first image has been taken form screen capture of full size image, then resized down. It shows the gritty look of the full size file. Once it is printed, or resampled to a size suitable for web viewing the gritty disappears, which is why I scaled down a screen capture of part of the full size image. The piece you see as full size is about twice to three times wider than your screen.

 

[ATTACH]11000[/ATTACH]

 

This second image is a crop from the resampled file. That is the original file, is resampled/resized to 1200 pixels wide, then I cropped this piece out rather than putting in the whole photo. Once resized/sampled the now smaller image loses all the gritty points and appears quite smooth and like one would expect to see on a photo.

 

[ATTACH]11001[/ATTACH]

 

I want to work on the full size file, but obviously judging adjustments to colour, contrast, sharpness and pretty much anything is a bit hard when you have an original file looks like this. And no you can't apply the same changes to the large file as you do the resampled file. A twelve percent change on the small file does not equal a twelve percent change in the large file. What is happening? And why?

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[imported_peter_m]

Rob,

I am not sure if I can answer but the way I see it is, you are viewing the original file at 100% that means it is displayed at your monitor at 72 ppi what will look quit cores, if you go and print this file say with a resolution of 216 ppi it would print out quit nice, in order to preview on your monitor how the print would look you would have to zoom to 33%.

 

If you go and resample that original image down to the 1200 pixels in the interpolation process the roughness of the full size viewed at 100% will be smoothened out and the smaller image will look better but then if you try to print it at the same resolution then the original you will have a much smaller print.

 

You can make all the adjustments to the full size and then resample down for web viewing.

 

Hope that makes sense.

 

Peter

[rob_x2004]

Peter, this is a part of screenshot of 33% view of the original file. It hasn't been resized or resampled.

 

[ATTACH]11003[/ATTACH]

[rob_x2004]

I guess the argument would be for paper priniting purposes, make your changes to the full size file ie tones contrast sharpening whatever, then make paper print. Burn a lot of paper because what you see is not what you get.

 

For web viewing reduce your file to the viewing size first, then make any ajustments because you are essentially working what you see is what you get.

 

Comments? Right or wrong?

[rob_x2004]

What about, if your printer is say a 300dpi, then resample to 300 x paper dimensions and then do photo editing?

[sreidvt]

Rob,

 

There are some strange artifacts in the first cropping you presented that I'd need to know more about to comment on. But as to your larger question: A 5400 ppi scan of 135 mm film will show not only the subject of the picture but also something of the physical structure of the material that picture was made on (including grain, of course). Remember that a scan is essentially a macro photograph of a piece of film. It's as if one was photographing a painting made on the side of a log cabin, the result will show not only the colors, composition, etc. of the painting but also the surface of the logs, the grain of the wood, etc.

 

As such, a scan can reveal much more about the physical aspects of the medium than we're used to seeing. When the scan is downsampled, much of the information about grain, etc. is resampled out. It's still best to do all of your editing with the full size scan and then reduce to size just before output. Otherwise, you can end up tossing scan information that you may later want when you go back to the file. I find that one can sometimes get a very general sense of how a picture may look when printed by viewing it at 50% on screen.

 

BTW, I own the same scanner and it's very good. FWIW, I tend to store the RAW files from the scan as well as the TIFFs when I archive to gold-based DVD.

 

Cheers,

 

Sean

[rob_x2004]

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Not sure I agree with this Sean .. It's still best to do all of your editing with the full size scan and then reduce to size just before output. Otherwise, you can end up tossing scan information that you may later want.

 

If I am working in a file I will store it as another name so the original info is always available, otherwise I have the neg somewhere.

 

If you are printing on a given paper size, with a printer at least calibrated to your monitor I think it might be better in some instances to work at the limit of the printers resolution times the paper size. Often I find it useful to see the effect of sharpening or colur adjustments before I print.

 

Also working on say a 120Meg file sometimes overloads the hardware and software. I guess a lot of people apply proprietry software so they do not have to think, but there are some aweful results out there. Curious that we bag a cameras program mode but are quite happy to apply a filter carte blanche when say the subject requires it, but the background certainly does not. Then people crap on about the lens bokah...go figure.

 

Anyway all the images are from the same file. If there are artifacts in one then they are in the other. The second image is resized with the 'atrifacts?' evened out, hence my question.

 

If I work on the original file size, even using the view to fit, the grainly look remains till I print or resample to post.

 

Regards

[sean_reid]

I suppose a lot of this will depend upon what your intended use for the final file is. These days, if I'm scanning film I'm preparing older work (mostly the 135mm subway pictures) for final prints. These scans are indeed about 75 MB but I don't mind that. That's enough for 17" x 24" at 300 ppi or just over 8" x 12" at 600 ppi. For book publication, the latter can be necessary. If one knows for sure that the largest print he or she will ever want to make from a given scan is X" by Y" then I suppose resampling to that size early on could work.

But if one is ultimately going to make some prints at size A, some at B, etc. then your method will require at least a double resampling in the process (one from full res. to working res. and the second from working res. to print res.). I prefer to avoid a double resampling and so I choose to prepare the file for final printing at full res. and then only downsize once to the final output size. But my goals and intentions for the scans may be different from your own. To each his own, I suppose.

 

Cheers,

 

Sean

[imported_peter_m]

Sean,

I agree with what you said and you sure did that a lot better then I ever could

I like to do most of my editing on the full size file, with the exception of sharpening, I find I get a bit better results if I sharpen just before I save the file for the intended use.

 

Rob,

 

One thing I found wile printing is to have even simple color management so all of your devices know what the color are supposed to be, if you are using PS it has quit good CM it will be just a matter of using the correct profiles for your printer.

Since I use a color managed system I never wasted to much paper my print outs pretty well match what I see on the screen.

 

Your printer output won't really effect the editing, it will only affect the printed output, if you say print at 300 dpi your printer will lay down 300 droplets of ink per inch, all of today's printers have a much higher resolution. The printer resolution defines how well the printer will render the printed image.

The image resolution will define how detailed your image is, at say 300 ppi it takes 300 pixels to make up that one inch, the two work together but you can't really mix them up.

 

In your samples you posted the resampled one looks good and the one at 33% view still looks grainy, you have to remember zooming in or out on an image isn't a proper resample the program uses some quicker logarithms to show you the reduced size, depending on editor, graphic card and monitor the quality of what you see may not reflect what you get in print.

 

Once you print a couple of files you should be able to tell what you will get in print from what you see on the screen.

 

That is just one thing I hate abut digital imaging, so many variables and so much software you have to rely on. Once you get it figured out it works smooth but it can be a bit of a drag getting there.

 

I better quit babbling here. getting to be past my bed time.

 

Peter

[sean_reid]

My decision that I wanted to move to digital capture about six years ago came from two things. The first was my realization that I wanted to work in Photoshop instead of the darkroom and the second was that scanning was second-generation digital photography. Once I knew that I was destined to live in the land of the pixel, it seemed best to me that I begin with the pixel and make the digital pictures of the subject rather than digital pictures of the negatives. With scanning, I realized, I would need to make a picture and then I would need to make another picture of my picture to get my pixels.

 

As I mentioned in another post today, film-based photography and darkroom work require a lot of knowledge too so, either way, there's lots to learn and practice.

 

BTW, I think these film vs. digital discussions (which largely died down a few years ago) are coming back up again here because the M8 is the first digital camera some film photographers would seriously consider. So, the discussion is not as much old news to them as it might be for some of us.

 

Cheers,

 

Sean