Question about scanning to really high resolutions for framing artwork purposes.

Hi,
If they originate as low resolution photos, then there is little point in trying to increase the resolution for printing 'big'. You'll just have to accept that the image will be as rough as @&*$ when it's printed out. Depending on the artwork in question, this is not necessarily a terrible thing, the effect can still be good.
You also have to take into account that one doesn't stand that close to an artwork of the size you are proposing, most viewers would typically stand about 3 or 4 feet away or more. This makes 'resolution' less important.
The big thing is the subject really, what is the subject of the artwork and how is it going to be affected by being magnified? If it is a straight photograph then the results will be poor. If it is something much more abstract and arty then it could work.
The closest I've ever done to this is I once scanned in some CD cover artwork and blew it up to about 600 x 600 mm. Obviously once this was done, the original CMYK screening was very visible but it still made for a good effect.
On the printer I've used over the last few years (an HP Designjet 130), I could get away with about 200dpi at output size for photographs, and it would still look pretty good printed out A1 (594mm x 841mm)
Note that this creates an image canvas of 4677 x 6622 pixels, the equivalent of a 30 megapixel camera, so unless you are taking photos with a very high megapixel latest generation digital SLR, you will still be 'blowing up' images for printing posters.
Sorry for rambling.
Edit: Noting your last question re. keeping images below 20mb, you need to output to JPEG but at a high as possible quality. High quality JPEGs are almost indistinguishable from TIFFs, although again it depends on the content of the image.

StephenCampbell said:

Is it possible to print a 200x300 image at a really really high quality so that you can scan it back in at 8000x12000 and have a full quality digital image of it .

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No. You can't add details that are lacking. The best you can hope for is a someway blurry large print. The worst is that it has blocky square pixels.

A 200x300 image is only able to be enlarged to a the size of a small print, maybe up to 4 inches wide at most before you start noticing defects

But now you say you have a 2x3 print. How was the print made? Perhaps is started from a larger than 200x300 file and has done on a good machine. Maybe it was from film?

The basic rule is that you can't create pixels from nothing

StephenCampbell said:

The image we fiddled with was a 480x591 digital image of an 18th century piece of art. I needed to get the horizontal resolution up to 7200 so that at a print of 24" by 29.54" it would be 300dpi on that physical print.

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You're thinking of bicubic interpolation. It does not "add" detail. It's just a method of scaling squared pixels larger. The point at which the delineation of details starts to break down is still about the same, only now it's large enough to be visible. You cannot add quality to small images off the web. You can resample it at a different size as you did there. If the quality is acceptable to you, then that's fine. It's not the same as you would get from a comparable native resolution. In the case of scanning either film or artwork, it depends on the resolution of the scanner, quality of the scanning lens, and the detail of the originals.

Photoshop can enlarge a photo, but it doesn't help much if your original image is a small.

People who don't know image manipulation typically think movie fiction (such as CSI "enhance") is real, but unfortunately it's not.

I am guessing you bought something from the museum? In that case the piece is probably available as a poster from the museum.

StephenCampbell said:

Am I right in assuming that there actually might not be any difference at all between those three files, since the source file was a 133KB file at 480x579? Am I not really going to be missing anything that could have been there if I use the 3.6MB 7200x8866 Jpeg? They really look the same to me.

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Are you viewing them at the same zoom percentage or scaling them to the same size on screen? I would genuinely like to see what you are describing. Resampling larger for large printing is nothing new, but you typically would not start with a tiny jpeg off the internet. I think this is one of those "pics or it didn't happen" situations.

StephenCampbell said:

Hah... sorry for the confusion. I meant that I don't see a difference between the 3.6MB 7200x8866 version that Preview created by resampling, vs the 191MB TIFF version that the guy at the copy place created for me.

My assumption is that there may really not be any practical difference between the 191MB TIFF and the 3.6MB Jpeg, since the source was of sufficiently low quality as to render the 3.6MB Jpeg perfectly capable of displaying everything that could be there.

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Oh that's different. The size of jpegs varies quite a bit depending upon the information in the photo. It just uses referencing to rebuild the image when you open it. Only a portion of the pixels are saved as full raster data. If they're close enough you'll never see the difference. At lower quality jpeg settings, you can start to to see the reduction of available colors when the image is opened. Anyway if you started with something significantly greater than that 480x579 image, it would have likely had more detail.

StephenCampbell said:

You mean the TIFF would show noticeably more detail than the Jpegs if it had begun as a higher quality image?

I'm actually very impressed with the quality of these Jpeg images when I resample them with Preview. I'm creating images now that are 600dpi and 30" vertical, and they remain under 20MB (the limit for fineartamerica.com) and look extraordinary. I can zoom in an incredible amount before I begin to see individual pixels. It seems very suited for a full framed printing.

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I'm sure you know this, but jpegs can be saved out at a range of compression values. Depending on the image and quality chosen, it can be an imperceptible difference. Assuming a reasonable value chosen for quality, you are only likely to run into possible trouble when adjusting it further. Sometimes you'll see problems in areas that depend upon subtle changes such as skies. If you save as a jpeg, edit, and resave as a jpeg repeatedly, you can take a much heavier quality loss. That's because it's applying new compression to the rebuilt image you opened. In practice if you're careful it shouldn't matter too much. Just save in a different format if you're still going to make several rounds of edits and don't take the quality slider too low. Also keep in mind the size as a jpeg is different from actual resolution.

StephenCampbell said:

What does your last sentence mean?

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I mean don't get too hung up on the size on disk as opposed to pixel dimensions. Different photos compress at different rates depending upon what values fall close enough to delete the original 24 bit values in favor of referenced ones at the chosen quality level. I say 24 bit specifically as jpgs cannot store RGBA (a being alpha). If you aren't sure what I mean, try saving a very large pure image of a pure white canvas. If everything is the same color, even high resolution imagery will result in small file sizes.

StephenCampbell said:

...... the detail is not any less than what I'd expect if I looked at a painting of that size from one foot away.

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Um, with all due respect - and no offence meant. You may want to spend more time going to museums and galleries.

StephenCampbell said:

You mean the TIFF would show noticeably more detail than the Jpegs if it had begun as a higher quality image?

I'm actually very impressed with the quality of these Jpeg images when I resample them with Preview. I'm creating images now that are 600dpi and 30" vertical, and they remain under 20MB (the limit for fineartamerica.com) and look extraordinary. I can zoom in an incredible amount before I begin to see individual pixels. It seems very suited for a full framed printing.

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Again, you can't digitally enlarge what's not there, no matter the image format or enlarge method. The original image is too small to enlarge for large print.

Otherwise there's no need for high end cameras that cost tens of thousands of dollars.

snberk103 said:

Um, with all due respect - and no offence meant. You may want to spend more time going to museums and galleries.

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Yup. Go to museums more, you can easily buy a high quality poster for cheap.

It sounds like the initial jpeg was of very high quality. Images vary, although I'm still somewhat surprised.

Do you mind uploading the said image, original and increased? I'm curious to see what CSI enhancement software you have.

To clarify, in your first post you said you want to create some art for your walls "that originate as low resolution digital photos" and you go on to say that "Is it possible to print a 200x300 image at a really really high quality".
I think perhaps I and a number of other posters on here are a little confused.
With regard to your 'original', when you say "a 200 x 300 image" do you mean:

1. a digital file of which the canvas size is 200 pixels by 300 pixels, or
2. a digital file of which the canvas size is 200mm by 300mm at a specific DPI, or
3. a physical photographic print at 200mm by 300mm, or......what?

because all three are very different things.

hmm

I just resized a roughly 600 x 400 pixel image of a Rennaissance painting to 7200x8866 with Photoshop expecting the result to be awful.

The result was surprisingly OK. Pretty blurry, but if you printed it on canvas and stood a few feet I guess many people would be happy to have it on their wall.

Lesson learned!

That seems to be a well known painting.

Go to tineye.com and search by image URL:
upload.wikimedia.org/wikipedia/commons/6/6a/Johann_Sebastian_Bach.jpg

There's a getty (probably expensive) version, but seems to be of an unrestored painting. So you can probably find a larger version.

The quality of the file is actually decent. It results in an OK enlargement that's could be ok for casual use.

StephenCampbell said:

Well, 200x300 was just an example... I don't actually have an image of that size. But it was referring to the pixels.

The actual image I was referring to is actually 480x591 pixels. It can be seen here. http://upload.wikimedia.org/wikipedia/commons/6/6a/Johann_Sebastian_Bach.jpg

If you open that image in Preview, and go Tools > Adjust Size... and then set it at 600 pixels/inch and a height of 30 inches, you'll get an image at 14619x18000 which looks to me very acceptable as you zoom in, and certainly good enough for a 24.37" by 30" framed print that will mostly be viewed by five feet away or more.

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