Scanning Kodachrome slides and Digital ICE

Kodachrome filmWhile ScanMyPhotos champions scanning of your photos to protect them from the unforeseen, we also feature professional 35mm slide scanning services. Each slide is individually hand scanned by our professional technicians, you can select to have each adjusted to achieve the optimum color and density so you end up with the best possible scan at either 2,000 or 4,000 dpi. One issue that arises though is scanning Kodachrome slides and trying to use the Digital ICE process. It is a very powerful scanning tool built into nearly all current slide scanners however, Kodachrome tends to be tricky to scan. First a little history and then we will discuss the issues that everyone faces when scanning Kodachrome.


What is Kodachrome?

Kodachrome is famous for, among other things, being the topic of a Paul Simon song, a U.S. State Park in Utah (Kodachrome Basin State Park) and being tricky to scan. The film itself was introduced by Kodak in 1935 but was discontinued in 2009 and nearly all processing of the film stopped in 2010. Since the film was discontinued, there was no reason for labs to continue processing the film since processing was complex and exacting, requiring technicians with extensive chemistry training and large, complex machinery. Think of them as the Walter Whites of film processing.


So why was Kodachrome so popular if it was so difficult and expensive to process? There were a number of reasons including the film’s long-term stability, which under suitable conditions were far superior to other types of color film, in addition to having better details in the shadows and deeper, richer colors compared to other film types. To put the comparison of the film types into digital photography terms, Kodachrome contained approximately 20 megapixels of data in the 24 mm x 36 mm image, whereas as other film contained about 12 megapixels of data at a comparable ISO rating.

How can I tell if I have Kodachrome slides?

 

The easiest way to recognize Kodachrome slides, but least reliable, is from the slide mount itself. Many labs that processed Kodachrome used special cardboard mounts that specifically say “Kodachrome” or “Kodachrome Transparency” while other labs used mounts where all of the printed text was printed red. The “red text” method is less reliable since it could have also just been the only mounts the lab had for all slides they processed.



The most reliable way to tell can be the most difficult method until you get some practice. Kodachrome slides will have a slight base relief effect on the emulsion side so the surface will not be perfectly smooth. No other type of slides have that same effect. What side is the emulsion side? If you are lucky, it is the side where the mount says “This side towards screen”. If it isn’t noted on the mount, just check both sides and if you don’t see the effect on either side, you know it isn’t Kodachrome. It can be hard to pick up at first while you tilt the slide back and forth under some light because the slide has to “catch” the light just right to see the effect however once you are able to see it, it is easy to replicate with other slides. With practice, you can learn to tell without having to hold it up to a light.

Side-by-side comparison of Kodachrome vs Ektachrome

Side-by-side comparison of Kodachrome vs Ektachrome. Note the “texture” on the Kodachrome slide. Click to enlarge.

Digital ICE and Kodachrome

 

“So, how does this affect my scans?” you may ask. Scanners have three channels, one for capturing red, one for green and a third for blue, however, scanners that implement Digital ICE also have a fourth infrared channel. The long wave infrared radiation easily passes through the film, but when it hits dusts, scratches and fingerprints, it does not pass through as easily. The internal workings of the scanner then piece together an image based on what the infrared channel found to “remove” the defects. The issue arises with Kodachrome and the unique developing process which creates various dyes on the film. Kodachrome interacts with the scanner’s infrared channel in two ways. The absorption of the cyan dye in the film extends nearly into infrared region, making this layer opaque to infrared radiation. Kodachrome film can also affect the infrared channel as it reflects the infrared light tricking the technology into thinking they are flaws.


These effects can sometimes cause a slight loss of sharpness in the scanned image when Digital ICE or a similar infrared channel dust removal function is used. In extreme cases, it can remove details altogether. I personally have see it remove a person’s eyes in one instance and in another, it entirely removed a small dog from a picture of it playing in the snow.

Kodachrome scanned poorly with Digital Ice

Click to see the effect in full detail. This sample is zoomed in to show greater detail of the effect and would be considered an extreme case.

Some people will say that “Digital ICE doesn’t work at all with Kodachrome,” while others claim that new scanners can easily handle Kodachrome slides while using Digital ICE. It has been our experience that neither is accurate but the truth lay somewhere in the middle. The truth is that is works much of the time just fine, but when it does go wrong, it produces completely unusable scans. Unfortunately, due to our proprietary scanners and software, we cannot simply turn Digital ICE on and off from scan to scan. We either have to have it on or off for an entire batch of scans. For this reason, when you purchase slide scanning from ScanMyPhotos, we have three options to choose from:

  • Scan all slides with Digital ICE on
  • Scan all slides with Digital ICE off
  • I will group my slides by type to be scanned with Digital ICE on and off accordingly

 

Grouping your slides by type will produce the optimum results but some prefer to have some chronology to their scans or perhaps all of the slides are in a carousel mixed all together which makes it hard to separate the types. In these cases, it is up to you. As noted, Digital ICE will work for many Kodachrome slides however there may be some here and there that produce poor results. If you have selected to have all of your slides scanned with Digital ICE on and you receive some “funky” results, we will rescan up to 15 slides per order for you at no charge with Digital ICE turned off. Simply contact our customer support team (www.scanmyphotos.com/CTUS.html) to discuss the rescanning process and mail the slides back to us for rescanning within 30 days of completion of your order.


For more insights and how to have all your Kodachrome 35mm slides professionally digitized, please click here.