Scanned 35mm slides.

[keithsloan]

I have a number of scanned 35mm slides ( Not sure if Kodochrome 64 or 25) when projected on a large screen at the camera club show a lot of defects. Is there anyway I can clean up such images? and if so what is the best way to go about it. 

[jscot]

I did a project a few years ago cleaning up old Kodachrome slides. And found applying a 1x or 2x Gaussian blur helped eliminate some of those specks. Especially in areas of sky, etc. 

[John Rostron]

I have many thousands of 35mm slides, now mostly scanned. I have found that there is no "one size fits all" solution. Many images will respond to a  quick 'Remove Dust and Scratches', but others will not. I find I have to resort to plugins for this. My first is usually the (free) Nik Dfine. If this fails, I use Imagenomic's Noiseware which usually does the trick. 

For the films you mention, grain is not usually a problem.

John

[AlainP]

I had around 600 color slides to scan. I didn't like the result using my HP scanner. I made a "light box" with daylight bulbs and a wood rack to which I installed a real plastic slide holder. I then used my camera on a tripod and a remote control. You then just change the slide an "click".... I got nice results. But... each and every slide has to be cleaned with a microfiber cloth and a small camera blower on each and each side of the slide to blow away the remaining dust. It takes more time but you then have so much less work to remove the dust in PP. Most of the remaining dust spot were removed using the Inpainting Brush tool. 

[John Rostron]

I now use SilverFast for scanning slides. It offers an additional infra-red channel which is supposed to detect any dust particles on the film, and then automatically correct the flaw. I have not yet put this to the test, but it is worth investigating. One disadvantage of SilverFast is the clumsy user interface. Another is that your software is dedicated to one source only, unlike VueScan which will work with any available scanner.  At one time SilverFast was an expensive option, but the basic version now costs €49, on a par with VueScan.

John

[Granddaddy]

Any software solution that "automatically" removes dust and scratches from images scanned from slides will inevitably degrade the image.

If possible, rescan the slides. Take care to remove dust from the slides and from the scanner before scanning .

Use a scanner with built-in dust and scratch removal technology such as FARE or ICE. These hardware techniques make a second infrared scan that distinguishes blemishes that are not part of the film image. It removes those blemishes from the saved image.

I've scanned more than 2,000 slides in the last few weeks on a Canon flatbed scanner. I took these photos some 50 to 60 years ago. Dust on the scans is simply not a problem.

Here's my procedure that I'll be using on the next several thousand slides:

1.) Clean scanner platen

2.) Brush both sides of slide with soft camel hair brush

3.) Blow dust from both sides of slide with Giottos Rocket Air Blaster

4.) Blow dust from scanner  platen with Blaster before setting slide in place

5.) Scan slides with Remove Dust and Scratches (FARE) set to Low

There may be occasional dust blemishes remaining but these are extremely rare in my experience. I just scanned some slides taken at Niagara Falls (lots of blue sky and white water) and thought there were some dust blemishes, but at full magnification they turned out to be birds over the Falls. Software dust removal might have taken them out.

Clean any remaining blemishes with Affinity Photo using Inpainting or cloning. This is tedious if near perfection is required, say for printing images for framing and for gifts. If the image is of special importance, it may be preferable to repeat the above steps and try again for a cleaner image That has been very rare in my experience.

My major problem with scanned slides is correcting color. I've found that Kodachrome 25 slides processed more than half a century ago by Kodak labs have retained their color quite well. But taking slides was expensive for me 60 years ago what with the cost of film, flashbulbs, and processing. In those days I took one or two photos of a scene, not the half dozen or more I take today when a photo costs nothing to take. Often I sent the film to labs other than Kodak to save a dollar or two in processing. Big mistake. Slides processed by alternative labs now have faded colors, often tending to be very blue. But that is easily corrected in Affinity with white balance and HSL adjustments. But again, such adjustment is tedious if you want to fix thousands of slides.

I'll be looking at batch processing for color correction, or reconsidering what I want to do with all these slides. My descendants may be less interested in them than I am. For now I am having a grand time showing my children and grandchildren the way we were.

 

 

 

 

[John Rostron]

I have a similar workflow, except that I used a slide scanner. 

You may be interested in the VueScan Bible by Sascha Steinhoff. It is expensive new, but I picked up one second hand.  Although it is about VueScan, the techniques can apply to other scanners as well.

One trick is to scan the slide twice, rotating it horizontally in between. You then rotate the second image in Affinity, and align and merge the two using whatever blending mode works best.

John

[v_kyr]

I once used a Nikon Coolscan 5000 a lot for scanning 35mm slides, which was used with NikonScan and Silverfast as scanning software. Even the scanner comes along with a whole range of image enhancement and image correction techniques, like automatic dust and scratch correction ICE/ICE4, film grain defect removal GEM, color restoration ROC and a newer DDE (which performs exposure corrections) and a Scan Image Enhancer, you later often have to additionally manually clean the scanned-in images.

One thing that for example often appears only over time on 35mm slides, beside dust and lint, are offcuts particles (from cutting slide strips) which are blown onto the slides via the Slide projector when in use etc. - Here one can intensively use a bunch of the Affinity Photo healing tools in order to remove that stuff from the digitized images.