Sunlight is a terrible source for color work. It is never white and varies wildly depending on conditions and surroundings (your lawn or your house paint). Do that indoors in the dark with a light source with color temperature, CRI etc. that suits your wallet.

All the cool kids are going to cameras, even to scan paper sheets. Check out this book scanner. http://arstechnica.com/gadgets/2013/02/ ... you-think/
There's a V-shaped gutter made of glass. The book is lifted up to it. There are cameras in the correct positions to snap both pages at once. The limiting factor is the human operator changing pages. It all goes into camera memory, so the PC isn't a limiting factor or even necessary.

LOL I remember when book scanning was controversial. Thanks for trailblazing, Google.

I'd recommend against using a digital camera to duplicate slides or other transparencies.

If you look at the image supplied below, the right side was scanned using a Microtek 9800XL at 1000dpi, the right side was using a Fuji FinePix S9450W digital camera using their "super macro" (1cm) focus capability with the slide on a light table using whatever florescent bulb that is in there.

Both images had their color/brightness levels done on Photoshop Elements using its auto level feature. Having the color balance off on the left is not to big a problem to correct.

The major issues are the pincushioning from the camera lens and some softness. Also the light saturation/contrast on the left image is more extreme The resolution seems about the same.

The other item is that the digital image is 72dpi from the camera, even though it is 4806x3456 pixels vs 2136x2000 scanned at 1000dpi. A little math tells me that there is an order of magnitude difference in information per pixel being captured between the two.

Given the work needed to correct the camera image, I'd stay with the scanner and just budget yourself accordingly.

Granted, shooting 1 image is quicker than scanning the slide, but you can scan in 6 slides (on a 12" wide bed) as quick as 1 can be & then use Photoshop to split them up.
The Microtek does supply a slide mask & software to create slide scans, but I misplaced it somewhere & couldn't use it in the test.

Considering that the sun was the original source of light for the slide, I don't see why sunlight would be a poor source for copying a slide.

Textbooks have been written all about the proper temperature of light for color reproduction. My wife, an artist, has them, and she throws fits over in what light she produces and displays her art. Suffice it to say "it's not that simple."

If all you were doing were re-shooting the original subject under the same sunlight as the original photo, that might suffice. But we're dealing with slide and negative films, each with their own known variations in reproduction, which are made to be exposed and projected with specific lighting requirements. Then you introduce a new factor by attempting to reproduce it digitally. All light, even all sunlight, is not created equally.

Part of the point of a slide scanner is consistency--you eliminate one potential variable by having the same light, diffusion, etc. no matter what you feed in.

Regarding book scanners, there's an important reason for their existence: repeatedly pressing bound books flat on a flatbed scanner inevitably destroys the binding, especially on older, fragile books. Both the high-end book scanners and the DIY model aim to reduce/eliminate that, in addition to increasing production rates.

Sunlight is good in that it's "full spectrum", that is all wavelengths are present, as opposed to some artificial light sources, which have significant gaps.

The problem with sunlight is it varies in color temperature - a lot - from somewhere around 3000K (very red) near dawn and dusk, to 5000K at high noon, to as high as 7000K (very blue) on an overcast day.

Actually, using a high megapixel digital camera to digitize slides and negatives is not only possible, but if done carefully, can rival the results from dedicated film scanners.

Take a look at this link:
http://www.luminous-landscape.com/essays/scannerless_digital_capture_and_processing_of_negative_film_photographs.shtml

The article deals with primarily negatives, but if you look at the PDF download in the article, you will see the setups the authors used. You could use any film type and adjust your process to fit. The primary thing to note is the authors used proper macro lenses optimized for shooting at close distances. If you slap any old lens on your digital SLR, your results will likely not be as good. The best method would be the use of a top quality enlarging lens with one of the slide duplicators of the past. Since digital cameras can adjust to most any light source by changing the color temperature, matching the color on slides should be easy. If you read the entire article, you will see that negatives are not as easy due to the masks they contain.

I have not tried this myself, but I'm considering it for 35mm slides. I own Nikon 9000 and Epson V750 scanners and while the scanners produce superb results, my chief complaint is the slow speed of scanning.

Not being very computer literate I'm wondering if the Epson V600 will work with my 2010 MacBook Pro which has a Thunderbolt instead of a firewire cable?

I've just joined the forum and this is a timely topic for me as I've got about 10,000 slides taken over the last 40 years that I'd like to digitize. I grew up living literally next to where 3 railroads crossed each other at grade level and there was a fourth railroad a half mile north so I'd like to be able to share the images.

To connect Firewire to Thunderbolt you just need one of these: http://store.apple.com/us/product/MD464 ... 29cd35447a

Perhaps a quick Google would reveal the correct interface to hook up an Epson V600. Hint, it's USB 2.0.

I have had very good results using a Plustek 8200i slide scanner. It scans four 35mm slides at a time, but you have to move the holder to scan each slide. Each scan takes about 45 seconds.

I get excellent color accuracy by simply using the software that comes with the scanner (known as Quickscan).

For black and white negatives, I use my Epson V700. I also use the Epson for plain flatbed scans of prints. There again, I use the Epson scanning software that comes with each scanner. For post-scan adjustments, I use both Photoshop and FastStone.

I've tried to capture my lessons-learned.

http://www.utahrails.net/tech-talk-photos.php

If you subscribe to Trainorders, I have uploaded test scans on several occasions, as I have worked my way through various projects over the past couple years. This includes comparisons between scanning slides on a flatbed scanner vs. a slide scanner.

Almost all the photos in these albums (below) were scanned by either the Plustek, and the Epson.

http://donstrack.smugmug.com/UtahRails

Don Strack

Thanks to everyone who responded!

After considering what was said here and the different options available, I purchased an Epson V550 scanner.

Today I scanned several negatives as a test sample, one of which is seen here (the scanner was set to the "Full Auto Mode"):

http://www.rrpicturearchives.net/showPicture.aspx?id=4048607

Barring sunspots, it's even a problem on the ISS. You know about moonshine, a full moon is bright enough to see at night. Ask any Apollo astronaut, earthshine is a lot brighter. And earthshine is not white. Generally it's blue, except on land masses where it tends to be green or brown, and that will change as the ISS rolls over it. So not a good place to use natural light to scan slides. Down here on the surface, it's much worse, because we're on the surface of the light "source". I'm looking out over a parking lot which is off gray, except for the bright spackles of colorful cars. Beyond the parking lot is a sea of green to the horizon. In a month it'll alternate between brown and white. And that is the light coming into my slide scanner.

The fact is, the daylight originally shot in was NOT good enough. But we made do with the daylight available, because we did not have cinematic gels large enough to white-balance the entire scene, nor a fleet of Zeppelins to hold them up. And yes, our cameras did faithfully capture the color of the light of the day, an effect you are well familiar with if you compare a lot of slides. Pro grade non-film cameras can "white balance" electronically, aim them at something gray, like a reference card or a Toyota, and push a button.

Full automatic color processing generally adjusts the contrast and brightness to make the image fill the defined depth of exposure. Lightest portions all the way white, darkest areas all the way black. The color is then adjusted to make white and black areas void of any color. With a nicely exposed slide with white and black contained within the image, just like tho one above, it will usually work great.

This thread may help.

viewtopic.php?f=1&t=31233&p=157223&hilit=slide+scanner

Here are 2 additional photos which I have scanned, both 35mm slides which I recently purchased and arrived in the mail today:

Scanned in professional mode at 9600 dpi, 24 bit color, resized to 4800 pixels wide. For these 2 photos, I selected unsharp mask (set to medium), color restoration, and digital ICE. For the photo of #8752, I also selected backlight correction.

CN Class MR-61-H-1 baggage #8752 (NSC, 1930) at Portland, ME, circa October 1969:

http://www.rrpicturearchives.net/showPicture.aspx?id=4056407



CN Class PB-79-A 76 seat coach #5630 (CC&F, Lot #2099, 1954) at Sarnia, ONT, on May 20th, 1974:

http://www.rrpicturearchives.net/showPicture.aspx?id=4056420



_________________
Additions and corrections are welcome. Thanks in advance.

Have a Merry Christmas!