Scan slides with auto-correction or automatic?

[chriss1]

I have a really big problem. I spent a lot of money for scanning three

Velvia films on Nikon 4000LS with auto-correction photo parameters.

Unfortunatelly, photos are too dark (darker than I can see on the

slides). I don't have any experience in scanning slides so ask for

advice: how to chose appropriate parameters while ordering scanning.

People in labs often ask about oversampling, individual or auto

exposure correction (per each slide) and etc. I thought that

auto-correction will be cheaper and the rest I'll improve in

Photoshop. I don't encourage anyone to try it again. Thanks in

advance.

[imaginator]

I'm no expert (but I play one on photo.net) Velvia can be harder to scan in the dense (dark) areas, especially if they are slightly underexposed. They may look OK on a light box, or even projected, but can be harder to scan than less contrasty films. It depends on the scanner... high end ("drum") scanners can do it, and some of the others with high D-max, dynamic range, ect. should work fine, but you might consider increasing exposure just a bit the next time you shoot (I just bracket when possible) If all the slides look about the same brightness, then there should be a way to have the scanner increase it's exposure or brightness (not sure, but some have an adjustment for this... it's not just software, but actually controls the hardware) Just to be clear on this... is the overall image dark, or just the shadows/darkest areas? Personally, unless the scanner has an actual hardware control over brightness/exposure, then I would just have the scans done with no correction. Here's a tip: next time you shoot some film, start the roll with a shot of a grayscale chart (or even just black, middle-gray, and white) This will help the lab (and you) see what corrections are needed.

[mendel_leisk]

Look into Vuescan and it's raw file concept. If you receive Vuescan raw files, you can do subsequent scan-from-disk from these files, just as if you were re-scanning, adjusting brightness etcetera. It can incorporate the infrared channel, detection of defects, as well.

[chriss1]

In fact, there are two ways: either they put slides into machine and receive to me ( or do first step and correct (in hardware) photos that they look right primary slides. All three DVDs I got have really big files (circa 120 MB each) 4000 DPi on 4.2 depth scanner (Nikon 4000). All slides are a bit darker but still OK. The worst are shadows where no details can be seen (for ex. sunset with nice sky and grassy ground on the slide has only good sky, the rest is totally black - in digital version). Photoshop operations can't restore details in shadows so I can only throw them away. In addition, some slides are blurred and grainy (with tripod..) that I can't understand (even I resize them double or trouble!) and (sic!) undersaturated - comparing to Velvia 50. Could anyone explain me the meaning of number oversampling? Maybe this will solve my trouble... Can 2x or 4x give better results than standard 1x or should I start searching a new lab with other scanner... Thank very much for both replies above with knowledge about scanning