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alanmole
5th of July 2004 (Mon), 22:19
Hi:

Decades ago wonderfully sharp prints called Laserprints became available, for film photos of course. I think they were made by scanning negatives, computer processing the files, and printing using lasers.

Ordinary landscape or architectural prints often featured blurry or fringed skylines and edges. Laserprints were sharp, Arizona Highways large format sharp.

I suppose the processing included sharpness algorithms (which, roughly, look for edges and place a white line of pixels on the light side and a very dark line on the dark side I think), and perhaps smoothing routines to remove patterns of grain or pixels from same-colored areas (e.g. blue and white patterns of pixels, sometimes tiny white rings around blue pixels, in areas of sky. These are probably how the original negative records the picture and are unobjectionable except when they become visible in extreme enlargement.)

I recently started digital photography, just for snapshots, with a 2 Mpxl Minolta Dimage X20. I had one picture enlarged to 5x7 on a Kodak self-service machine, and was amazed by the quality. It was sharp even under a magnifier. Perhaps this is part illusion -- little detail masked by sharp edges. Regardless, it looked sharp. I'd like to do something similar for some very sharp, fine grained (Kodachrome ASA 25) slides and similar negatives.

My questions are :

Is this what Laserprints actually were, or have I got it wrong?

Can I have slides and old negatives scanned and processed this way, obtaining apparently higher sharpness and detail than with conventional old fashioned enlargements?

Can I do this myself? Are there 35mm scanners at reasonable prices that will see the full resolution (up to 160 lines/mm, or at least 100)? Would I then need an expensive program like Photoshop or will most simple programs do most of these things now?

Does the Laserprint company still exist, and do they do a better job than on line printers etc.?

BTW, I am thinking in terms of 24x30 inch enlargements from good 35 mm negatives and slides made with a Pentax Spotmatic and 50MM lens that tests to 160 lines/mm. Even if I process the files I'd have the actual prints made commercially -- I don't want to buy a huge high resolution inkjet printer.

Thanks, and any help appreciated,

Alan Mole

robertwgross
5th of July 2004 (Mon), 22:38
Straightforward film/slide scanners will do 4000 lines per inch in two directions. From a 35mm slide, you get an image file of anywhere between 50MB and 150MB depending on the color depth you choose (24 bits or 42/48 bits).

From a file that size, I can do some noise/grain reduction and then print just about as large as I want.

Alternatively, I could interpolate upward, refine the image, and then print out. Refinement might include adjusting sharpness for the final print size.

The only bad thing about going this route is that it becomes a huge time sink.

---Bob Gross---