Scanning, resolution and printing

[Meekyman]

Hi Folks,

I'm new to LF photography and scanning and all that that involves. My driver for trying out LF photography is the potential for detail rich images that print at good size (to A3 for now) and exploiting movements. For the moment I am sending out some negatives/slides for scanning to a commercial outfit using an Epson V750. The cost is moderate (£2 per negative/slide) and the purpose is for me to get something that will allow for digital printing.

So, I requested a TIFF scan at 2000 ppi. For a 5x4 negative thats 10000x8000 pixels, so 80MP. Maths right? When I look in photoshop, the native size of this scan is something like 8.87x 11.34 cm. So, if I want an A4 scan I need to upsize, right? Wont that result in detail loss? I regularly print at 300 dpi, so I could thereby in theory enlarge 6.66 times on each dimension (2000/300). Right? So, an image of just over 30 x 24 inches?

Well when I enlarge the scanned image to even A4, loss in resolution is noticeable if I use 300 dpi. Should I keep it at 2000 ppi and have a huge file instead?

Any clear help would be really appreciated...as I'm quite liking playing with my wooden camera!

I know a drum scan would provide huge images. Maybe for exceptional images, but surely something like an Epson V700/V750 would be good enough for A4?

Thanks

Graham

[Peter De Smidt]

You have a 4" x 5" scan at 2000 dpi. In Photoshop's "Image Size" dialogue box, uncheck the "resample image" box. Now highlight the number in the the resolution box, in this case 2000 dpi. Type in 300. Your image size will now change to about 26.6" by 33.3". None of this has effects the the image information in the file, as no resampling has been done. This gives you the maximum size that can be printed at 300 dpi without resampling.

But if you want to print smaller than that, a better way to do this is to again bring up Photoshop's "Image Size" dialogue box. Make sure that the "re-sample" check box is not checked. In the image dimensions areas, enter the dimensions of your final print. As long as it's smaller than the max size listed above, your resolution will be greater than 300. That's no problem and should actually give slightly better results than printing at 300. With an Epson, I regularly send a file from a scanned 4x5" negative at 720 dpi to the printer. Some people think that you should re-size to either 300, 360, 480 or 720 dpi, but I don't agree.

Whatever you do, make sure to keep a couple of copies of the original file.

[rich815]

Peter puts it well. And I agree with the last point and changing the dpi, I've tried many ways and some are adamant about a need to "match" the printer but after going thru Epson 1160, 870, 2200, 1200 and now using a 3880 printer, I find it does not matter, at least in a way of viewing the print normally or after being matted and framed. Maybe under a microscope?

Lastly, get a used 4990 or 750 scanner and learn to do the scanning yourself. I find after the exposure and proper development of the neg the scanning step is so very very important. When I sent negs out for scanning a few times they almost always came back too contrasty and often had shadows or highlights clipped. Remember, never scan for the best post-scan "look", scan to capture a much wide detail and tonality as possible so you can work with the neg on tonality in terms of curves or levels. The scan should look quite flat and boring right at scan time. Then with only minor PS work you can make it come alive. But too often scanning services feel they need to deliver a good-looking final scan which too often gives you a scan file with little potential to work with.

[Meekyman]

Thanks Peter and Rich,

That really made sense and when looking at my images using what you suggested I was pretty impressed at the detail. Even without sharpening, scary detail.

My journey goes forward...just hope film is around for some time!

Best wishes

Graham

[Lenny Eiger]

I know a drum scan would provide huge images. Maybe for exceptional images, but surely something like an Epson V700/V750 would be good enough for A4?
Thanks
Graham

Graham,

A drum scan is not about making giant images. There are two specific benefits. The first is that drum scans come out sharp, and need almost no sharpening at all. This maintains image quality. The second is that PMT's (the PhotoMultiplier tubes that drum scanners use) are much more sensitive than CCD's (that flatbeds use). If you are interested in subtlety, very smooth tonal transitions, etc., a drum scanner is a superior tool.

Finally, if one scans a piece of film to best quality possible, then one can "archive" the image in another media other than the film itself. Color film does degrade over time and this is usually a good idea. Since film is ultimately fading there will be no more advances in scanning technology and what we have today is very likely the best one will ever get. I like a "scan it once" philosophy where it gets scanned to full quality, then you can do whatever you want with it. If you scan it this way, 2 or 10 years from now if you want to make a larger one you won't have to scan it again.

Drum scanners are available these days for about $1500. That's not much more than a 750 costs, in real terms. It isn't a 100:1 difference...

There is one benefit to having your own scanner, whichever it is, and that is that you can scan the film over and over until you get it right.

I would suggest that any one who is thinking of spending any money on either ought to have someone knowledgeable do a scan on both and see which one they like before spending hard earned cash. There's nothing like hard evidence. Just my 2 cents....

Lenny

[Peter Gomena]

+1

I bought some drum scans made on a Heidelberg Tango for the first time this past summer. No sharpening needed, and you can work the files like crazy without noticeable image degradation - and these were 8-bit files! My take on this is that my Epson 750 is fine for most things, but that the occasional image merits a drum scan.

[Ivan J. Eberle]

Drum scanners were originally designed for the prepress printing industry and 4 color CMYK printing needs. What need there is for scanners today is the fine art market. Can't find many/any color transparency films now; 8-bit scans SUCK for color negative scanning.

[Corran]

You have a 4" x 5" scan at 2000 dpi. In Photoshop's "Image Size" dialogue box, uncheck the "resample image" box. Now highlight the number in the the resolution box, in this case 2000 dpi. Type in 300. Your image size will now change to about 26.6" by 33.3". None of this has effects the the image information in the file, as no resampling has been done. This gives you the maximum size that can be printed at 300 dpi without resampling.

But if you want to print smaller than that, a better way to do this is to again bring up Photoshop's "Image Size" dialogue box. Make sure that the "re-sample" check box is not checked. In the image dimensions areas, enter the dimensions of your final print. As long as it's smaller than the max size listed above, your resolution will be greater than 300. That's no problem and should actually give slightly better results than printing at 300. With an Epson, I regularly send a file from a scanned 4x5" negative at 720 dpi to the printer. Some people think that you should re-size to either 300, 360, 480 or 720 dpi, but I don't agree.

Whatever you do, make sure to keep a couple of copies of the original file.

In my experience, sending a file to be printed that is way over the nominal 300 DPI is an easy way to get a terrible image.
The printer resizes it to its native DPI, and depending on the image and printer, the results could be disastrous. I've gotten heinous moire effects from this resizing.

In the digital photography classes I teach, I emphasize that they MUST resize every image that is going to a printer to the native resolution of that printer, and make sure it looks good at that size (final sharpening/retouching should be done at that resolution).

[Peter De Smidt]

As far as I know, the native file resolution of many Epson printers is 720. If I have that, that's what I send to the printer, even though that's much more than 300 dpi. I see an improvement, albeit a small one. I'm not sure where the recommendation for 300 dpi comes from, at least with Epson. Some people say that one should send a file such the the resolution of the file results from dividing the native resolution of the printer by a whole number. For example, with a 600 dpi printer, 300 would be a good choice. With a 720 dpi printer, 360 would be a good choice... But I haven't found that to be the case. That said, I print with a RIP and so I'm not sure if the Epson driver behaves differently. In his book Ctein said that he could seen an improvement with increasing the dpi of the file up to about 500 dpi. As always, though, one should test this with one's particular system. It's not hard to do.

[Corran]

I certainly agree with testing. I tell my students to investigate exactly what the native DPI for their printer or the printer their printing service uses for optimal results (and I just know that's 300 DPI for the printing services I use).

I imagine that a whole-number division would be easily accommodated by any resizing algorithm, hence that suggestion. My worst experience was a 12mp digital file that had startrails that I forgot to resize for a 5x7 print. It literally had moire from the startrails across the entire sky due to the resizing artifacts.

[Lenny Eiger]

I imagine that a whole-number division would be easily accommodated by any resizing algorithm, hence that suggestion. My worst experience was a 12mp digital file that had startrails that I forgot to resize for a 5x7 print. It literally had moire from the startrails across the entire sky due to the resizing artifacts.

I think testing on one's own system is the ticket. I am not going to say you didn't experience this, but it has never occurred to me, I have never had any degradation from sending a print over the "native" dpi, even way over that number. It is also possible that something else is occurring... that isn't about the 300... or the 720?

Lenny